Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris

Chris Styles wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris



Unless there are damp problems that you can conclusively attribute to
rising damp (which would be unusual), leave well alone, and tell any
mortgage lender that you'll go elsewhere if they're not happy with that.

Chris Styles wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris


I'm pretty sure that re-plastering would really only be necessary if
there was rising damp that had left salt stains in the existing plaster
near to floor level.

You don't say whether there is any evidence of rising damp. It is also
possible that the vendors have done a quick disguise by using stain
blocking paint so a *proper* independent damp survey would be a good idea.

Of course, a damp proofing company might say differently as most of the
work and perceived value and thus cost, is the removal of the old
plaster and the re-plastering.

Sorry, no idea of cost.

Steve

On Mon, 29 Oct 2007 12:14:33 -0000, "Chris Styles"
wrote:

Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.


We were quoted £650 by Dampco for two inside walls - one about 7 foot
long and one about 4 foot. This included removal and replacement of
plaster but not radiators present.
On moving into the property, we see no signs of damp at all - dunno
what Dampco were detecting but I can't see or fell or smell anything
at all, so we have just left it alone..

On my old house, we had the front exterior wall done (15 foot long)
and it cost £1000 25 years ago.

Stuart Noble wrote:
Chris Styles wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't
have a
damp course.

After spinning her an elaborate story about having the entire house
sliced
out of the terrace and lifted up on blocks while a damp course is
fitted, I
promised to ask around to find out how much she should expect to pay
to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster
had to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

I think it's almost a given that if they inject a DPC, in order to offer
the magic and worthless guarantee which is required to satisfy the
lender, it will be required to rip off the bottom metre of plaster back
to the brickwork, and replace with Special sand/cement-based plaster.
Hell of a mess.

Unless there are damp problems that you can conclusively attribute to
rising damp (which would be unusual), leave well alone, and tell any
mortgage lender that you'll go elsewhere if they're not happy with that.

I totally agree with the sentiments but she'll end up in just the same
situation with any other mortgage lender (paying an arrangment/valuation
fee each time) will the possible exception of a specialist lender who
deals in and understands period properties, but are unlikely to be able
to match the mortgage deals offered by the big boys.

David

In article ,
Chris Styles wrote:
A friend is looking to buy a Victorian Terraced house, and it doesn't
have a damp course.

Neither do any in this street in London.

After spinning her an elaborate story about having the entire house
sliced out of the terrace and lifted up on blocks while a damp course is
fitted, I promised to ask around to find out how much she should expect
to pay to have a chemical DPC done.

Not actually so silly - I've seen a mechanical damp course inserted by
'sawing the wall in half'. And it's likely to work rather better than a
chemical one which is a con.

I seem to recall someone else having the chemical DPC, and it requiring
a certain amount of replastering to be done after, because the plaster
had to be stripped back at the bottom of the wall. Is this normal (or
even anything to do with the DPC?)

Well, yes. If you have damp showing - for whatever reason - removing the
old plaster and replacing it with waterproof skim plus plaster will stop
the damp showing again - at that spot.

Any hints, tips gratefully received.

Do a Google and you'll find plenty advice. Suffice it to say true rising
damp is extremely rare - otherwise those houses would have been built with
one in the first place. Most causes of actual damp are cause by water
penetration - patios etc added afterwards not draining water away from the
walls.

--
*Money isn't everything, but it sure keeps the kids in touch *

Dave Plowman London SW
To e-mail, change noise into sound.

"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Colin Bignell

nightjar wrote:
"Chris Styles" wrote in message
...

Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Colin Bignell


Do you have a link for this study Colin?

As said, its a waste of time. The usual solution is to get a
competent specialist to put in writing that such treatment is not
appropriate and not needed, then BSs will usually say ok to that.

These folk
http://periodpropertyshop.co.uk/phpB...wforum.php?f=1
could probably point you to someone capable of the job.


NT

nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Colin Bignell



One wonders why damp courses ever became standard practice

Chris Styles wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.


Biggest problem is that while injecting outer walls is relatively easy,
inner walls are less so, and chimneys are damn near impossible.

Forget the arseholes who say that rising damp doesn't exist BTW, it damn
well does and it is a nightmare if you want to turn a draughty open
fired house into a cosy des res.

In general apart from DP injection, you have two or three other lines of
attack.

Firstly lowering the local water table: you create a gravel filled moat
round the property and drain it. Easy if on high or sloping ground,
requires pump and a sump if lower down.

Secondly waterproof tanking up the inside walls. This works by basically
making sure that as the damp travels upwards, it doesn't come inside
until its had a damn good chance to evaporate outwards. This works well
on single brick with no cavity but not well on cavity walls unless they
are airbricked and even then its not that hot. And of course is some
**** has decided your problem was penetrating damp, cos he listened to
some other ****, and has waterproofed the walls outside, you are in deep
**** anyway.

Finally. whatever is left, you control with heat and ventilation. Damp
per se is only a problem if it leads to blown plaster, mould or rotting
wood.





Chris

nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.


Well it made about a foot in my old house up 18th century porous brick.

Quite enough to rot all the floor timbers and blow all the plaster above
the skirting.


Colin Bignell

Stuart Noble wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't
have
a
damp course.

After spinning her an elaborate story about having the entire house
sliced
out of the terrace and lifted up on blocks while a damp course is
fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it
requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for
prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good
ventilation
is far more important for avoiding damp problems.

Colin Bignell



One wonders why damp courses ever became standard practice
Indeed.

In article , The Natural
Philosopher wrote:
The Building Research Establishment did extensive tests, to try to
detect rising damp, by standing various building materials in water
for prolonged periods. They concluded that damp does not rise more
than, at most, a few inches, which implies that the DPC is entirely
superfluous. Good ventilation is far more important for avoiding damp
problems.


Well it made about a foot in my old house up 18th century porous brick.

Quite enough to rot all the floor timbers and blow all the plaster above
the skirting.

And just how old were the timbers and plaster? And if it were rising damp
due to no damp course would have caused these problems many times in the
house's life?

Of course if you concrete round the outside of a house where there used to
be drainage you can often get damp penetrating through porous bricks, etc.
But that's not rising damp.

--
*Why is the word abbreviation so long? *

Dave Plowman London SW
To e-mail, change noise into sound.

wrote:
nightjar wrote:

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Do you have a link for this study Colin?

IIRC it was one that Jeff Howell was involved in or at least reported in
some depth - there seems to be much less info about it on his site now,
but I think the graphs in this link refer to the same study:

http://www.askjeff.co.uk/content.php?id=3

David

On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris

Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.
The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.
Rising damp does exist. It is not particularly rare. The problem is
the specialists do egg it a lot and class bridged dpcs and latereral
penetration as rising damp. That may account for more than 50% of the
houses treated - unnecessarily! Plastering is NOT always needed and
not necessarily for 1 m - the standard distance. That is normally to
protect the interests of the company rather than the client. When my
firm was contracting in this field (1979) we did it for 1 year and
decided that it was simply not worth doing because the profit margin
was too low and most of the houses we visited did not have true rising
damp needing treatment. We got calls out for condensation - pipe leaks
- bridge dpcs - you name it!
your friend needs to do several things
1) establish that there really is no dpc - they have been mandatory
since 1886 and could have been bridged by soil and concrete paths
2) IF NO dpc - then borrow or buy a damp meter and plot readings in
all walls on an isometric sketch of the affected areas over a period
of several months at times of high and low RH. Any variation in the
tide mark indicates RD. There should be a pattern of readings
starting from the top of no damp at say 1 m down to very damp at say
800 mm then slightly damp below that at the top of the skirting.
check the skirtings - are they wet (greater than say 14 w/w ) if so
you may have some form of dampness
3) get at least three free surveys - select using the following
criteria a) full members of the PCA (ex BWPDA) b) offering GPT back up
guarantee c) most importantly insist the surveyor has the CSRT
qualifiation
these three will not ensure you get a good survey but will cut out
an awful lot of crap
4) USE YOUR COMMONSENSE in intermpreting the results and dont take
them as Gospel - most firms have their intersts at heart
5) If there is dampness but the plaster is not visually damaged - take
a risk - put in the dpc but delay the replastering for a year and see
if it dries out - that saves a lot of money
6) understand that the rising damp does not occur in the bricks so
drilling the bricks is a waste of time- It occurs in the mortar. Ask
the firm if they drill the bricks (trick question) If they say "Yes"
show them the door and explain that you wanted someone who understood
they needed to drill the mortar not the brick to put the hydrophobic
layer in the mortar
7) the best dpc (in my opinion) is one using a silane based compound -
trade name "Dryzone" from Safeguard Chemicals - you can buy it and diy
See the website
Costs - these vary from firm to firm but a good diy can negotiate
reductions by taking off skirtings where needed for them and doing the
hacking off themselves


8) read up on the BWPDA (now PCA) code of practice for DPC s which is
similar to that of the BS which is also worth reading
Both are a bit out of date but show the principles.

Come back to me if you need further help
Chris

Dave Plowman (News) wrote:
In article , The Natural
Philosopher wrote:
The Building Research Establishment did extensive tests, to try to
detect rising damp, by standing various building materials in water
for prolonged periods. They concluded that damp does not rise more
than, at most, a few inches, which implies that the DPC is entirely
superfluous. Good ventilation is far more important for avoiding damp
problems.


Well it made about a foot in my old house up 18th century porous brick.

Quite enough to rot all the floor timbers and blow all the plaster above
the skirting.

And just how old were the timbers and plaster?

Timbers? probbly 200 years

Plaster? looked like 70's

And if it were rising damp
due to no damp course would have caused these problems many times in the
house's life?

Indeed. It obviously had.

Some patching had improved it, other patching had trapped rot inside.

Plastering over what had been brick chimneys sealed its fate.


Of course if you concrete round the outside of a house where there used to
be drainage you can often get damp penetrating through porous bricks, etc.
But that's not rising damp.

Er..concrete round a house does not affect damp being sucked up in the
middle of it by the chimney.

When w finally took it apart, there was a small pond under the floor and
the chimney stood in the middle of it.

wrote:
On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris

Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.

Er no. In my case it appeared directly the day after heavy rain, and was
due to RAPID - hours only - build up of a lake beneath the floor, that
was sucked up by the chimney brickwork, and by another transverse wall
that had NOT been injected.

The OUTSIDE WALLS THAT HAD BEEN INJECTED, WERE FREE FROM IT.

In this matter I can totally agree with ne point

"An awful lot of unscientific, unsubtantiated assertions are made about
rising damp."

And you are the guilty party.

The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.

A lot depends on the brick and the mortar, Old soft brick and lime
mortar sucks like a whore.

Put in modern cement and the mortar courses themselves act as a
primitive DPC.

Everyone KNOWS how much bricks will suck water out of mortar. The
question is what is the set mortar like? Lime mortar is soft and porous,
and no barrier to the passage of water. This may, or may not be, the
property you like about it.

"The Natural Philosopher" wrote in message
...
nightjar cpb@ wrote:
....
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for
prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good
ventilation
is far more important for avoiding damp problems.


Well it made about a foot in my old house up 18th century porous brick.

The theortical lift in a glass tube of 0.2mm diameter, which should be more
effective at producing a straight lift from capillary action than the
variable size passageways in a brick, is 14cm, although the theoritcal lift
is not normally achieved. That suggests that either you have a reduced force
of gravity in your house, or a higher than normal surface tension in your
water, or it was not rising damp.

Colin Bignell

Lobster wrote:
wrote:
nightjar wrote:

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Do you have a link for this study Colin?

IIRC it was one that Jeff Howell was involved in or at least reported in
some depth - there seems to be much less info about it on his site now,
but I think the graphs in this link refer to the same study:

http://www.askjeff.co.uk/content.php?id=3

David

Thanks - I just wish the BRE study were online somewhere


NT

The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.

The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.


Well it made about a foot in my old house up 18th century porous brick.

Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.


NT

wrote:
On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris

Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.
The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.
Rising damp does exist. It is not particularly rare. The problem is
the specialists do egg it a lot and class bridged dpcs and latereral
penetration as rising damp. That may account for more than 50% of the
houses treated - unnecessarily! Plastering is NOT always needed and
not necessarily for 1 m - the standard distance. That is normally to
protect the interests of the company rather than the client. When my
firm was contracting in this field (1979) we did it for 1 year and
decided that it was simply not worth doing because the profit margin
was too low and most of the houses we visited did not have true rising
damp needing treatment. We got calls out for condensation - pipe leaks
- bridge dpcs - you name it!
your friend needs to do several things
1) establish that there really is no dpc - they have been mandatory
since 1886 and could have been bridged by soil and concrete paths
2) IF NO dpc - then borrow or buy a damp meter and plot readings in
all walls on an isometric sketch of the affected areas over a period
of several months at times of high and low RH. Any variation in the
tide mark indicates RD. There should be a pattern of readings
starting from the top of no damp at say 1 m down to very damp at say
800 mm then slightly damp below that at the top of the skirting.
check the skirtings - are they wet (greater than say 14 w/w ) if so
you may have some form of dampness
3) get at least three free surveys - select using the following
criteria a) full members of the PCA (ex BWPDA) b) offering GPT back up
guarantee c) most importantly insist the surveyor has the CSRT
qualifiation
these three will not ensure you get a good survey but will cut out
an awful lot of crap
4) USE YOUR COMMONSENSE in intermpreting the results and dont take
them as Gospel - most firms have their intersts at heart
5) If there is dampness but the plaster is not visually damaged - take
a risk - put in the dpc but delay the replastering for a year and see
if it dries out - that saves a lot of money
6) understand that the rising damp does not occur in the bricks so
drilling the bricks is a waste of time- It occurs in the mortar. Ask
the firm if they drill the bricks (trick question) If they say "Yes"
show them the door and explain that you wanted someone who understood
they needed to drill the mortar not the brick to put the hydrophobic
layer in the mortar
7) the best dpc (in my opinion) is one using a silane based compound -
trade name "Dryzone" from Safeguard Chemicals - you can buy it and diy
See the website
Costs - these vary from firm to firm but a good diy can negotiate
reductions by taking off skirtings where needed for them and doing the
hacking off themselves


8) read up on the BWPDA (now PCA) code of practice for DPC s which is
similar to that of the BS which is also worth reading
Both are a bit out of date but show the principles.

Come back to me if you need further help
Chris

fair bit of misinformationn here too


NT

wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Well it made about a foot in my old house up 18th century porous brick.

Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.


Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.




NT

wrote:
wrote:
On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris
Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.
The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.
Rising damp does exist. It is not particularly rare. The problem is
the specialists do egg it a lot and class bridged dpcs and latereral
penetration as rising damp. That may account for more than 50% of the
houses treated - unnecessarily! Plastering is NOT always needed and
not necessarily for 1 m - the standard distance. That is normally to
protect the interests of the company rather than the client. When my
firm was contracting in this field (1979) we did it for 1 year and
decided that it was simply not worth doing because the profit margin
was too low and most of the houses we visited did not have true rising
damp needing treatment. We got calls out for condensation - pipe leaks
- bridge dpcs - you name it!
your friend needs to do several things
1) establish that there really is no dpc - they have been mandatory
since 1886 and could have been bridged by soil and concrete paths
2) IF NO dpc - then borrow or buy a damp meter and plot readings in
all walls on an isometric sketch of the affected areas over a period
of several months at times of high and low RH. Any variation in the
tide mark indicates RD. There should be a pattern of readings
starting from the top of no damp at say 1 m down to very damp at say
800 mm then slightly damp below that at the top of the skirting.
check the skirtings - are they wet (greater than say 14 w/w ) if so
you may have some form of dampness
3) get at least three free surveys - select using the following
criteria a) full members of the PCA (ex BWPDA) b) offering GPT back up
guarantee c) most importantly insist the surveyor has the CSRT
qualifiation
these three will not ensure you get a good survey but will cut out
an awful lot of crap
4) USE YOUR COMMONSENSE in intermpreting the results and dont take
them as Gospel - most firms have their intersts at heart
5) If there is dampness but the plaster is not visually damaged - take
a risk - put in the dpc but delay the replastering for a year and see
if it dries out - that saves a lot of money
6) understand that the rising damp does not occur in the bricks so
drilling the bricks is a waste of time- It occurs in the mortar. Ask
the firm if they drill the bricks (trick question) If they say "Yes"
show them the door and explain that you wanted someone who understood
they needed to drill the mortar not the brick to put the hydrophobic
layer in the mortar
7) the best dpc (in my opinion) is one using a silane based compound -
trade name "Dryzone" from Safeguard Chemicals - you can buy it and diy
See the website
Costs - these vary from firm to firm but a good diy can negotiate
reductions by taking off skirtings where needed for them and doing the
hacking off themselves


8) read up on the BWPDA (now PCA) code of practice for DPC s which is
similar to that of the BS which is also worth reading
Both are a bit out of date but show the principles.

Come back to me if you need further help
Chris

fair bit of misinformationn here too


pot, kettle.

NT

On Oct 31, 8:44 am, "nightjar" cpb@insert my surname here.me.uk
wrote:
"The Natural Philosopher" wrote in . net...

nightjar cpb@ wrote:
...
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for
prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good
ventilation
is far more important for avoiding damp problems.

Well it made about a foot in my old house up 18th century porous brick.

The theortical lift in a glass tube of 0.2mm diameter, which should be more
effective at producing a straight lift from capillary action than the
variable size passageways in a brick, is 14cm, although the theoritcal lift
is not normally achieved. That suggests that either you have a reduced force
of gravity in your house, or a higher than normal surface tension in your
water, or it was not rising damp.

Colin Bignell

Or that the typical hole size in the brick is less than 0.2mm? (I
would have expected the lift height to be roughly inversely
proportional to the hole size for "small but not atomic" sizes.)

On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Well it made about a foot in my old house up 18th century porous brick.

Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.

Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.
Not taking sides here, but how do you know it wasn't condensation?
Elsethread you refer to this being the chimney - it sounds possible to
me that warm(ish), moist, internal air could rise up the chimney,
cool, and condense - leaving the chimney wet. (I am assuming the
fireplace wasn't in use of course).

Martin Bonner wrote:
On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,
A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.
After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.
I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)
Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.
Well it made about a foot in my old house up 18th century porous brick.
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.
Not taking sides here, but how do you know it wasn't condensation?
Elsethread you refer to this being the chimney - it sounds possible to
me that warm(ish), moist, internal air could rise up the chimney,
cool, and condense - leaving the chimney wet. (I am assuming the
fireplace wasn't in use of course).

Sigh. Because it happened a day *after* it *rained heavily*. Without
fail. Using the chimneys helped a lot.

Also on one spine wall, it appeared UNDER a layer of plastic bags the
previous owner had placed UNDER the carpet. To prevent it discolouring.

Total lift up from the soggy clay underneath would have been about a
foot or so.

On Oct 31, 1:45 pm, The Natural Philosopher wrote:
Martin Bonner wrote:
On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,
A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.
After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.
I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)
Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.
Well it made about a foot in my old house up 18th century porous brick.
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.
Not taking sides here, but how do you know it wasn't condensation?
Elsethread you refer to this being the chimney - it sounds possible to
me that warm(ish), moist, internal air could rise up the chimney,
cool, and condense - leaving the chimney wet. (I am assuming the
fireplace wasn't in use of course).

Sigh. Because it happened a day *after* it *rained heavily*. Without
fail.
Fair enough!

Using the chimneys helped a lot.
Of course. (Althogh that's not diagnostic of where the water was
coming from)

Also on one spine wall, it appeared UNDER a layer of plastic bags the
previous owner had placed UNDER the carpet. To prevent it discolouring.

Total lift up from the soggy clay underneath would have been about a
foot or so.
It is difficult to see how it could be anything other than rising damp
doesn't it. I wonder why the BRE results were so different. Two
options spring to mind:
1. They weren't, and are being (innocently) misremembered
2. They tested modern bricks and/or modern mortar.

Martin Bonner wrote:
On Oct 31, 1:45 pm, The Natural Philosopher wrote:
Martin Bonner wrote:
On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...
Hi,
A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.
After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.
I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)
Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.
Well it made about a foot in my old house up 18th century porous brick.
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.
****.
There was no 'outside wall' idiot.
THEY were dry - THEY had been injected. It was only the INTERIOR walls.
Not taking sides here, but how do you know it wasn't condensation?
Elsethread you refer to this being the chimney - it sounds possible to
me that warm(ish), moist, internal air could rise up the chimney,
cool, and condense - leaving the chimney wet. (I am assuming the
fireplace wasn't in use of course).
Sigh. Because it happened a day *after* it *rained heavily*. Without
fail.
Fair enough!

Using the chimneys helped a lot.
Of course. (Althogh that's not diagnostic of where the water was
coming from)

Also on one spine wall, it appeared UNDER a layer of plastic bags the
previous owner had placed UNDER the carpet. To prevent it discolouring.

Total lift up from the soggy clay underneath would have been about a
foot or so.
It is difficult to see how it could be anything other than rising damp
doesn't it. I wonder why the BRE results were so different. Two
options spring to mind:
1. They weren't, and are being (innocently) misremembered
2. They tested modern bricks and/or modern mortar.

I think that is fairly relevant actually.

I know fom my own bricklayng experimens that tudor/17th century bricks
are soft and friable, and soak up water out of mortar like nothing.
Cheaper modern bricks are similar, bu good quality modern bricsk are `
heap different.

Likewise teh fact that peoel use string portlanmd cement mortars to
'tank' up wdamp walls sows that that is also a relevant factor. Indeed
the proponents of lime mortar argue that its 'breathable' porous nature
is what makes it so good: In the context of rising damp IMHO its a
fecking disaster.

Damp arguments aways devolve to whether its better to help it get out,
or stop it getting in.

My logic says as long as it gets out faster than it gets in and via a
place where it won't rot wood or screw up plaster, all is well and good.

It is vital to establish how its getting in tho: tanking up the outside
of a wall with rising damp under the impression its penetrating damp
will make things worse, forcing moisture to the inside of the house.

Ive got a little bit of it myself. I have a loose slate in the wetroom
floor and patch f wall in te corridor shows efflorescence about 6"
above floor level..Must fix hat..theres a stud wall nearby.

so who's going to get the credit card out, there is a bit of an
introduction
http://www.brebookshop.com/details.jsp?id=287528
looks like they do believe in rising damp.

On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
wrote:
On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris
Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.
The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.
Rising damp does exist. It is not particularly rare. The problem is
the specialists do egg it a lot and class bridged dpcs and latereral
penetration as rising damp. That may account for more than 50% of the
houses treated - unnecessarily! Plastering is NOT always needed and
not necessarily for 1 m - the standard distance. That is normally to
protect the interests of the company rather than the client. When my
firm was contracting in this field (1979) we did it for 1 year and
decided that it was simply not worth doing because the profit margin
was too low and most of the houses we visited did not have true rising
damp needing treatment. We got calls out for condensation - pipe leaks
- bridge dpcs - you name it!
your friend needs to do several things
1) establish that there really is no dpc - they have been mandatory
since 1886 and could have been bridged by soil and concrete paths
2) IF NO dpc - then borrow or buy a damp meter and plot readings in
all walls on an isometric sketch of the affected areas over a period
of several months at times of high and low RH. Any variation in the
tide mark indicates RD. There should be a pattern of readings
starting from the top of no damp at say 1 m down to very damp at say
800 mm then slightly damp below that at the top of the skirting.
check the skirtings - are they wet (greater than say 14 w/w ) if so
you may have some form of dampness
3) get at least three free surveys - select using the following
criteria a) full members of the PCA (ex BWPDA) b) offering GPT back up
guarantee c) most importantly insist the surveyor has the CSRT
qualifiation
these three will not ensure you get a good survey but will cut out
an awful lot of crap
4) USE YOUR COMMONSENSE in intermpreting the results and dont take
them as Gospel - most firms have their intersts at heart
5) If there is dampness but the plaster is not visually damaged - take
a risk - put in the dpc but delay the replastering for a year and see
if it dries out - that saves a lot of money
6) understand that the rising damp does not occur in the bricks so
drilling the bricks is a waste of time- It occurs in the mortar. Ask
the firm if they drill the bricks (trick question) If they say "Yes"
show them the door and explain that you wanted someone who understood
they needed to drill the mortar not the brick to put the hydrophobic
layer in the mortar
7) the best dpc (in my opinion) is one using a silane based compound -
trade name "Dryzone" from Safeguard Chemicals - you can buy it and diy
See the website
Costs - these vary from firm to firm but a good diy can negotiate
reductions by taking off skirtings where needed for them and doing the
hacking off themselves

8) read up on the BWPDA (now PCA) code of practice for DPC s which is
similar to that of the BS which is also worth reading
Both are a bit out of date but show the principles.

Come back to me if you need further help
Chris

fair bit of misinformationn here too

pot, kettle.

NT

The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...

Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)

Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.

Well it made about a foot in my old house up 18th century porous brick.

Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.


Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.


I figured the reply would be less than logical. Walls with their feet
in water tend to be colder, and walls are always coldest
at the bottom anyway, so its no surprise when condensation
occurs there.


NT

The Natural Philosopher wrote:
Martin Bonner wrote:
On Oct 31, 11:03 am, The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:
nightjar cpb@ wrote:
"Chris Styles" wrote in message
...

Hi,
A friend is looking to buy a Victorian Terraced house, and it doesn't have
a
damp course.
After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted,
I
promised to ask around to find out how much she should expect to pay to
have
a chemical DPC done.
I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had
to
be stripped back at the bottom of the wall. Is this normal (or even
anything
to do with the DPC?)
Any hints, tips gratefully received.
The Building Research Establishment did extensive tests, to try to detect
rising damp, by standing various building materials in water for prolonged
periods. They concluded that damp does not rise more than, at most, a few
inches, which implies that the DPC is entirely superfluous. Good ventilation
is far more important for avoiding damp problems.
Well it made about a foot in my old house up 18th century porous brick.
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

****.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.
Not taking sides here, but how do you know it wasn't condensation?
Elsethread you refer to this being the chimney - it sounds possible to
me that warm(ish), moist, internal air could rise up the chimney,
cool, and condense - leaving the chimney wet. (I am assuming the
fireplace wasn't in use of course).

Sigh. Because it happened a day *after* it *rained heavily*. Without
fail. Using the chimneys helped a lot.

which conicidentally just happens to be when water content of the
soil is at it highest, and RHg is high too. Uhuh - must be rising
then.


Also on one spine wall, it appeared UNDER a layer of plastic bags the
previous owner had placed UNDER the carpet. To prevent it discolouring.

right, ties in with greater ground water content then.


NT

The Natural Philosopher wrote:

pot, kettle.

Hardly a logic based line of reasoning, but hey.


NT

On Nov 1, 12:23 am, wrote:
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.

Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.

There was no 'outside wall' idiot.

THEY were dry - THEY had been injected. It was only the INTERIOR walls.

I figured the reply would be less than logical. Walls with their feet
in water tend to be colder, and walls are always coldest
at the bottom anyway, so its no surprise when condensation
occurs there.

Boggle! Outside walls tend to be colder still, and injecting a DPC
won't warm the wall up (so it would still get condensation). I think
you are clutching at straws here.

I don't think the Natural Philosopher is suggesting that all dampness
in all houses is due to rising damp - and to do so would be
ridiculous.

It is not ridiculous to ask "Is it possible that no dampness in any
house is caused by rising damp", but there comes a point where it /is/
ridiculous to continue to avoid the evidence that "at least part of at
least one wall is damp because of rising damp" (to misquote the old
joke about black sheep in Scotland).

Martin Bonner wrote:
On Nov 1, 12:23 am, wrote:
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.
There was no 'outside wall' idiot.
THEY were dry - THEY had been injected. It was only the INTERIOR walls.
I figured the reply would be less than logical. Walls with their feet
in water tend to be colder, and walls are always coldest
at the bottom anyway, so its no surprise when condensation
occurs there.

Boggle! Outside walls tend to be colder still, and injecting a DPC
won't warm the wall up (so it would still get condensation). I think
you are clutching at straws here.

I don't think the Natural Philosopher is suggesting that all dampness
in all houses is due to rising damp - and to do so would be
ridiculous.

It is not ridiculous to ask "Is it possible that no dampness in any
house is caused by rising damp", but there comes a point where it /is/
ridiculous to continue to avoid the evidence that "at least part of at
least one wall is damp because of rising damp" (to misquote the old
joke about black sheep in Scotland).


Condensation can usually be discounted if the damp is the same all year
round.
That just leaves the rising/penetrating discussion. My experience over
the years suggests the latter is invariably the culprit but, as this
involves time-consuming remedial work to the walls, people would rather
think about something else

Stuart Noble wrote:
Martin Bonner wrote:
On Nov 1, 12:23 am, wrote:
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.
There was no 'outside wall' idiot.
THEY were dry - THEY had been injected. It was only the INTERIOR walls.
I figured the reply would be less than logical. Walls with their feet
in water tend to be colder, and walls are always coldest
at the bottom anyway, so its no surprise when condensation
occurs there.

Boggle! Outside walls tend to be colder still, and injecting a DPC
won't warm the wall up (so it would still get condensation). I think
you are clutching at straws here.

I don't think the Natural Philosopher is suggesting that all dampness
in all houses is due to rising damp - and to do so would be
ridiculous.

It is not ridiculous to ask "Is it possible that no dampness in any
house is caused by rising damp", but there comes a point where it /is/
ridiculous to continue to avoid the evidence that "at least part of at
least one wall is damp because of rising damp" (to misquote the old
joke about black sheep in Scotland).

My point was it can be either, and he doesnt apear to have
established which. That leaves both options open. I'm not trying to
start taking guesses or propose extreme positions.


Condensation can usually be discounted if the damp is the same all year
round.

I wish it were so, it would make life esier. Unfortunately
condensation does occur in summer with a small minority of
properties.


That just leaves the rising/penetrating discussion. My experience over
the years suggests the latter is invariably the culprit but, as this
involves time-consuming remedial work to the walls, people would rather
think about something else

Indeed. But dont rule out leaks causing unnecessarily high interior
RH or running own cavities.


NT

Stuart Noble wrote:
Martin Bonner wrote:
On Nov 1, 12:23 am, wrote:
Be interesting to hear how you determined that the water rose up
the wall, rather than being lateral penetration or condensation.
Because there was no way other than that it could get up what was
essentially a pillar in the middle of the house.
There was no 'outside wall' idiot.
THEY were dry - THEY had been injected. It was only the INTERIOR walls.
I figured the reply would be less than logical. Walls with their feet
in water tend to be colder, and walls are always coldest
at the bottom anyway, so its no surprise when condensation
occurs there.

Boggle! Outside walls tend to be colder still, and injecting a DPC
won't warm the wall up (so it would still get condensation). I think
you are clutching at straws here.

I don't think the Natural Philosopher is suggesting that all dampness
in all houses is due to rising damp - and to do so would be
ridiculous.

It is not ridiculous to ask "Is it possible that no dampness in any
house is caused by rising damp", but there comes a point where it /is/
ridiculous to continue to avoid the evidence that "at least part of at
least one wall is damp because of rising damp" (to misquote the old
joke about black sheep in Scotland).


Condensation can usually be discounted if the damp is the same all year
round.
That just leaves the rising/penetrating discussion. My experience over
the years suggests the latter is invariably the culprit but, as this
involves time-consuming remedial work to the walls, people would rather
think about something else

Actually mostly it doesn't.

Ive had plenty of penetrating damp too - the old cottage was basically
falling to pieces from damp, and had been for years and many bodges had
happened. But some good things still existed like drip boards, to throw
rain off walls. Where they had not rotted away that is..

Put decent overhangs on your eaves, pay attention to guttering and
drain round the house well to avoid splashback, and your walls stay
remarkably dry even in torrential rain. In the final analysis something
nasty like pebbledash will give the house a plastic mac as it were.

Of course its usually just after that has been done that the rising
damp., now locked in, starts to find its way out via the interior
plaster ;-)

On 31 Oct, 10:57, wrote:
wrote:
On 29 Oct, 12:14, "Chris Styles" wrote:
Hi,

A friend is looking to buy a Victorian Terraced house, and it doesn't have a
damp course.

After spinning her an elaborate story about having the entire house sliced
out of the terrace and lifted up on blocks while a damp course is fitted, I
promised to ask around to find out how much she should expect to pay to have
a chemical DPC done.

I seem to recall someone else having the chemical DPC, and it requiring a
certain amount of replastering to be done after, because the plaster had to
be stripped back at the bottom of the wall. Is this normal (or even anything
to do with the DPC?)

Any hints, tips gratefully received.

Chris

Dear Chris
An awful lot of unscientific, unsubtantiated assertions are made about
rising damp. You do not have to look further than the opinions
expressed above to get a feel of it.
As best I can I will give you a resume of what happens.
Rising damp is caused by the migration of a solution of inorganic
salts from the ground into the plaster and bricks of a wall over a
long period of time - decades. It is NOT water per se that is the
problem but the water that is abstracted from the atmosphere at times
of high RH.
The reason the BRE experiment did not work is probably because the
chaps doing it could not reproduce the conditions in a building over a
period of say 50 years. I happen to know most of them and they are not
the only ones to have tried the idea of putting brick columns in ponds
of water and testing dpcs this way. ~The University of the South Bank
did a similar experiment with similar lack of sucess and drew a
disimilar conclusion.
Rising damp does exist. It is not particularly rare. The problem is
the specialists do egg it a lot and class bridged dpcs and latereral
penetration as rising damp. That may account for more than 50% of the
houses treated - unnecessarily! Plastering is NOT always needed and
not necessarily for 1 m - the standard distance. That is normally to
protect the interests of the company rather than the client. When my
firm was contracting in this field (1979) we did it for 1 year and
decided that it was simply not worth doing because the profit margin
was too low and most of the houses we visited did not have true rising
damp needing treatment. We got calls out for condensation - pipe leaks
- bridge dpcs - you name it!
your friend needs to do several things
1) establish that there really is no dpc - they have been mandatory
since 1886 and could have been bridged by soil and concrete paths
2) IF NO dpc - then borrow or buy a damp meter and plot readings in
all walls on an isometric sketch of the affected areas over a period
of several months at times of high and low RH. Any variation in the
tide mark indicates RD. There should be a pattern of readings
starting from the top of no damp at say 1 m down to very damp at say
800 mm then slightly damp below that at the top of the skirting.
check the skirtings - are they wet (greater than say 14 w/w ) if so
you may have some form of dampness
3) get at least three free surveys - select using the following
criteria a) full members of the PCA (ex BWPDA) b) offering GPT back up
guarantee c) most importantly insist the surveyor has the CSRT
qualifiation
these three will not ensure you get a good survey but will cut out
an awful lot of crap
4) USE YOUR COMMONSENSE in intermpreting the results and dont take
them as Gospel - most firms have their intersts at heart
5) If there is dampness but the plaster is not visually damaged - take
a risk - put in the dpc but delay the replastering for a year and see
if it dries out - that saves a lot of money
6) understand that the rising damp does not occur in the bricks so
drilling the bricks is a waste of time- It occurs in the mortar. Ask
the firm if they drill the bricks (trick question) If they say "Yes"
show them the door and explain that you wanted someone who understood
they needed to drill the mortar not the brick to put the hydrophobic
layer in the mortar
7) the best dpc (in my opinion) is one using a silane based compound -
trade name "Dryzone" from Safeguard Chemicals - you can buy it and diy
See the website
Costs - these vary from firm to firm but a good diy can negotiate
reductions by taking off skirtings where needed for them and doing the
hacking off themselves

8) read up on the BWPDA (now PCA) code of practice for DPC s which is
similar to that of the BS which is also worth reading
Both are a bit out of date but show the principles.

Come back to me if you need further help
Chris

fair bit of misinformationn here too

NT- Hide quoted text -

- Show quoted text -

Dear meow2,
Particulars (of misinformation) please?
Chris G

On Nov 1, 11:58 am, wrote:
Dear meow2,
Particulars (of misinformation) please?
Chris G

Don't worry he's a period property 'loony'

Interesting site here BTW:

http://www.konrad-fischer-info.de/2auffen.htm

cheers,
Pete.

Pete C wrote:
On Nov 1, 11:58 am, wrote:
Dear meow2,
Particulars (of misinformation) please?
Chris G

Don't worry he's a period property 'loony'

Interesting site here BTW:

http://www.konrad-fischer-info.de/2auffen.htm

cheers,
Pete.

Note two things

Early on thee page he says "No ascending dampness by capillarity, but
consequence of current splash-water, water sucking cement joints" =
rising damp!.

Look at the brick wall in the pool of water. Makes my case that modern
cement is a DPC in itself . Note he has NOT used lime mortar here.

Look at how sodden the brick is UP to the first mortar joint.


Whilst I am happy to agree that many so called rising dmp problems are
not, in older properties it does exist and is a serous isue IF you want
to modernise them.

If you leave the chimneys open, burn coal and don't plaster the walls or
fit double glazing, why? that's how they were designed in the first
place!. Draughty (well ventilated) and heated by a means that would
RAPIDLY dehumidify them in winter, and with the windows wide open all
summer, and no wood anywheree near the brcks..not that lasts more than
60 years, anyway.

The issue comes when you have a 100 year old place built out of soft
brick and lime mortar with no DPC and you want to at least make it un
draughty and use CH. Here injection will work. IF you can get to all the
walls. But if its single brick I'd just s soon put in a concrete floor
WITH DPM And insulation and possibly UFH as well), run that up the walls
and tank over up to about 2 ft, or better still, dry line it with foil
backed board and celotex, and let all that dees come up get outside, not
inside.

A chimney or spine wall is always gong to be a bugger. Its just always
going to be damp at the base. You can't really inject very sucessfully.
Rally you have perhaps just two choices..tank it up and cover it in
render, or let t BE a chimney and tank it up where you want to plaster
over it, and put some sort of waterproofing between it, and any wooden
flooring etc.

Frankly a victorian semi or terrace is my idea of hell anyway. I'd pull
the ****ers down and build something better on the land personally. But
there you go. Victorain rectories and decent gerorgian hosuses are worth
keeping tho. They tend to have been better built to start with. A lot of
victorian stiff wasn't built to last and it hasn't. Theres not a lot of
timber framed 300 year old stuff around either - when I pulled mine down
I found out why ;-) It wsa allegedly a farm building originally - almost
a barn. Never built to last, or house people, but somehow it did.

On Nov 1, 4:53 pm, The Natural Philosopher wrote:

Early on thee page he says "No ascending dampness by capillarity, but
consequence of current splash-water, water sucking cement joints" =
rising damp!.

You could at least quote the sentance properly, it says:

"No ascending dampness by capillarity, but consequence of current
splash-water, water sucking cement joints AND EARLIER ANIMAL HUSBANDRY
(FOLLOWS MINERAL SALTPETER (SODIUM NITRATE))

With 'rising damp', water is only half of it, the other half is
HYGROSCOPIC SALTS.

Theres not a lot of
timber framed 300 year old stuff around either - when I pulled mine down
I found out why ;-) It wsa allegedly a farm building originally - almost
a barn.

E-X-A-C-T-L-Y!!!

Never built to last, or house people, but somehow it did.

Probably lasted longer than much current housing will.

cheers,
Pete.