The problem (sorry it's a bit long):

Moved into our 150 year old house (soft brick and no DPC) a year and a
half ago. I knew there were some damp issues and I've addressed some in
other parts of the house, but we've just stripped the wallpaper off one
room and the problems are a lot more severe than I thought.

The house is on a hill and this room is "underground" - there is no
earth touching the walls as there are retaining walls outside with a
gap between those and the house.

The room has always felt damp (black mould etc.) but I originally
thought the problems were due to condensation. I've now pretty well
ruled that out though. The whole house is well heated and there are few
sources of water vapour.

The room has 2 external and 2 internal walls:
- external wall 1: has no windows. Plaster has blown over full length
up to a height of about 2 ft. No evidence of injected DPC but plaster
has been replaced on lower half of wall previously.
- external wall 2: contains 1 window. Wall in fairly good condition.
Evidence outside of injected DPC. No evidence that plaster has been
replaced.
- internal wall 1: plaster blown over full length up to height of
about 1ft. Plaster on lower half of wall has been replaced previously.
Opposite side of wall has been drylined.
- internal wall 2: has radiator. According to previous owner this has
had DPC injected and plaster replaced about 5 years ago. Plaster coming
away either side of radiator. Opposite side of wall is a fully tiled
bathroom (rarely used). The only pipes in or on this wall are radiator
pipes which are fully visible and not leaking.

The floor doesn't seem to be damp (carpeted). The skirting is made from
quarry tiles. This area used to be the cellar of a large manor house.
The ceiling (and floor of room above) is made from 14" thick reinforced
concrete.

Where the plaster has blown the brick feels quite damp. The plaster
that has not blown doesn't feel particularly damp. There are no pipes
etc. except for the radiator. The rainwater goods are in good order.
The floor level outside is about the same as the floor level inside,
made from concrete and drains away from the house. I'm convinced this
is rising damp.

The solution:

I know all the stuff about old properties - that you should allow the
walls to breathe and and have lots of ventilation etc. but I can't
really see that being practical!

This room has obviously been a problem for some time and has had many
attempts to solve the damp issues.

I'm wondering whether the best course of action would be to dryline the
whole thing. I would imagine I would need to use some sort of vapour
barrier and treated batons. Does anyone have any idea how long this
arrangement would last?

Any other ideas? I've seen membrane systems that you bury under the
floor and run right up to the ceiling before plastering over, but as
the floor is not damp I don't think this is necessary.

Any more suggestions would be very welcome!

Bodgit wrote:

The problem (sorry it's a bit long):

Moved into our 150 year old house (soft brick and no DPC) a year and a
half ago. I knew there were some damp issues and I've addressed some in
other parts of the house, but we've just stripped the wallpaper off one
room and the problems are a lot more severe than I thought.

The house is on a hill and this room is "underground" - there is no
earth touching the walls as there are retaining walls outside with a
gap between those and the house.

The room has always felt damp (black mould etc.) but I originally
thought the problems were due to condensation. I've now pretty well
ruled that out though. The whole house is well heated and there are few
sources of water vapour.

The room has 2 external and 2 internal walls:
- external wall 1: has no windows. Plaster has blown over full length
up to a height of about 2 ft. No evidence of injected DPC but plaster
has been replaced on lower half of wall previously.
- external wall 2: contains 1 window. Wall in fairly good condition.
Evidence outside of injected DPC. No evidence that plaster has been
replaced.
- internal wall 1: plaster blown over full length up to height of
about 1ft. Plaster on lower half of wall has been replaced previously.
Opposite side of wall has been drylined.
- internal wall 2: has radiator. According to previous owner this has
had DPC injected and plaster replaced about 5 years ago. Plaster coming
away either side of radiator. Opposite side of wall is a fully tiled
bathroom (rarely used). The only pipes in or on this wall are radiator
pipes which are fully visible and not leaking.

The floor doesn't seem to be damp (carpeted). The skirting is made from
quarry tiles. This area used to be the cellar of a large manor house.
The ceiling (and floor of room above) is made from 14" thick reinforced
concrete.

Where the plaster has blown the brick feels quite damp. The plaster
that has not blown doesn't feel particularly damp. There are no pipes
etc. except for the radiator. The rainwater goods are in good order.
The floor level outside is about the same as the floor level inside,
made from concrete and drains away from the house. I'm convinced this
is rising damp.

The solution:

I know all the stuff about old properties - that you should allow the
walls to breathe and and have lots of ventilation etc. but I can't
really see that being practical!

This room has obviously been a problem for some time and has had many
attempts to solve the damp issues.

I'm wondering whether the best course of action would be to dryline the
whole thing. I would imagine I would need to use some sort of vapour
barrier and treated batons. Does anyone have any idea how long this
arrangement would last?

Any other ideas? I've seen membrane systems that you bury under the
floor and run right up to the ceiling before plastering over, but as
the floor is not damp I don't think this is necessary.

Any more suggestions would be very welcome!

To understand why its damp and how to solve it, ask on
http://periodpropertyshop.co.uk/phpB...wforum.php?f=1
and read the damp faq first.


NT

To understand why its damp and how to solve it, ask on
http://periodpropertyshop.co.uk/phpB...wforum.php?f=1
and read the damp faq first.

I've read the FAQ. I'm pretty sure I understand why it's damp.

Our house is a wing of an old manor house. In the 1850s this area of
the house (17' square) was a coal cellar. The room next door (20' x
17') was a boiler room. The kitchen (20' x 17') was above. When it was
built it probably didn't matter that it was damp - the coal-fired
boilers, kitchen and open windows would have kept things pretty well
under control. And if the coal cellar was a bit damp who cares? It was
never designed to be lived in. But that's what we're trying to do.

I'm aware of your oppinion that rising damp doesn't exist. But in this
case I think that's exactly what it is (yes - quite possibly brought
about by the concrete floors that were laid in the seventies).

If I were to ask on PP, I'd be told to rip off all the plaster,
re-plaster with lime plaster, take up the concrete floors and get some
reed matting instead of carpets. I don't want to do this - I want a
practical solution. I know that we've 'asked for it' by messing around
with the natural breathability of the house. And I know that any
solution would probably not last forever. I just want to make the room
livable.

Bodgit wrote:

To understand why its damp and how to solve it, ask on
http://periodpropertyshop.co.uk/phpB...wforum.php?f=1
and read the damp faq first.

I've read the FAQ. I'm pretty sure I understand why it's damp.

Our house is a wing of an old manor house. In the 1850s this area of
the house (17' square) was a coal cellar. The room next door (20' x
17') was a boiler room. The kitchen (20' x 17') was above. When it was
built it probably didn't matter that it was damp - the coal-fired
boilers, kitchen and open windows would have kept things pretty well
under control. And if the coal cellar was a bit damp who cares? It was
never designed to be lived in. But that's what we're trying to do.

I'm aware of your oppinion that rising damp doesn't exist.

Thats not my opinion.

But in this
case I think that's exactly what it is (yes - quite possibly brought
about by the concrete floors that were laid in the seventies).

If I were to ask on PP, I'd be told to rip off all the plaster,
re-plaster with lime plaster, take up the concrete floors and get some
reed matting instead of carpets. I don't want to do this - I want a
practical solution.

I think youre jumping to conlcusions before theyre due there, you
really dont know until you ask. The solutions I've seen on ppuk tend to
be a good deal more practical than other approaches offered IME.


I know that we've 'asked for it' by messing around
with the natural breathability of the house. And I know that any
solution would probably not last forever.

why not?

I just want to make the room
livable.

I think your assumptions may be getting in the way.


NT

In article .com,
"Bodgit" writes:
The problem (sorry it's a bit long):

Moved into our 150 year old house (soft brick and no DPC) a year and a
half ago. I knew there were some damp issues and I've addressed some in
other parts of the house, but we've just stripped the wallpaper off one
room and the problems are a lot more severe than I thought.

The house is on a hill and this room is "underground" - there is no
earth touching the walls as there are retaining walls outside with a
gap between those and the house.

Can you inspect it? Is the gap clear of any debris?
Is is running with water?

The room has always felt damp (black mould etc.) but I originally
thought the problems were due to condensation. I've now pretty well
ruled that out though. The whole house is well heated and there are few
sources of water vapour.

That alone doesn't rule it out.
For example, if those walls are remaining colder than the air
temperature, they could be forming condensation. Have you checked
the temperature of the walls where they are damp (need an Infra-red
thermometer for this). Given the air temperature and humidity, it
is possible to look up the dew point (temperature below which the
wall will form condensation).
See: http://www.tis-gdv.de/tis_e/misc/klima.htm
For example, a room at 20C air temperature and 50% humidity will
cause condensation on a wall at a temperature of 12C or lower.

The room has 2 external and 2 internal walls:
- external wall 1: has no windows. Plaster has blown over full length

Blown plaster is not necessarily a sign of damp. It could have
been blown a week after being plastered, due to poor plastering.

--
Andrew Gabriel

Can you inspect it? Is the gap clear of any debris?
Is is running with water?

Yes - the retaining walls are about 4ft from the house walls so it's
easy to walk around. The space between the two is filled with concrete
which is about at the internal floor level and slopes away from the
house into an open channel that runs along the bottom of the retaining
wall. The only damp area outside is at the bottom of the retaining wall
- the channel gets a bit full of leaves sometimes and water can sit
there, but it's not against the house.

That alone doesn't rule it out.
For example, if those walls are remaining colder than the air
temperature, they could be forming condensation. Have you checked
the temperature of the walls where they are damp (need an Infra-red
thermometer for this). Given the air temperature and humidity, it
is possible to look up the dew point (temperature below which the
wall will form condensation).
See: http://www.tis-gdv.de/tis_e/misc/klima.htm
For example, a room at 20C air temperature and 50% humidity will
cause condensation on a wall at a temperature of 12C or lower.

Thanks for the info. I'll do that when I get home in a few days' time.
I can accept that the external walls may suffer from condensation - the
dadmage may well have been done before we moved in. But the internal
walls must all be at around the same temperature, so I would have
thought that if one wall suffered then they all would. I'll check with
the IR thermometer and get back to you.

Blown plaster is not necessarily a sign of damp. It could have
been blown a week after being plastered, due to poor plastering.

The wall feels wet though! I'm quite prepared to drill a hole in the
wall to see whether the wetness is on the surface or penetrating right
through. Anyone care to suggest a technique for doing this?

- external wall 2: contains 1 window. Wall in fairly good condition.
Evidence outside of injected DPC. No evidence that plaster has been
replaced.

In that case maybe all the walls should be injected. Better to do that
yourself to ensure the right amount of fluid is used (I don't trust
contractors). Damp on the lower part of an internal wall strongly
suggests that it's rising, and this would be a low cost first step.

The solution:

I know all the stuff about old properties - that you should allow the
walls to breathe and and have lots of ventilation etc. but I can't
really see that being practical!

This room has obviously been a problem for some time and has had many
attempts to solve the damp issues.

I'm wondering whether the best course of action would be to dryline the
whole thing. I would imagine I would need to use some sort of vapour
barrier and treated batons. Does anyone have any idea how long this
arrangement would last?

Wooden battens wouldn't last long on the wet side of the barrier. I
suppose you could use plastic and stainless steel fixings, but I
wouldn't embark on anything that drastic before trying other options.
You'd be losing space and would have to line up the new surface with
windows and doors somehow.

I know of one property round here where foil faced plasterboard was
slapped directly on to damp brickwork during "renovation". The internal
walls still look good 5-6 years later, so I guess they got away with it.

Any other ideas? I've seen membrane systems that you bury under the
floor and run right up to the ceiling before plastering over, but as
the floor is not damp I don't think this is necessary.

Any more suggestions would be very welcome!


Let us know if you get anything useful from PP. As you say, restoring
the place as a coal cellar isn't really an option here.

In that case maybe all the walls should be injected. Better to do that
yourself to ensure the right amount of fluid is used (I don't trust
contractors). Damp on the lower part of an internal wall strongly
suggests that it's rising, and this would be a low cost first step.

I'm prepared to give it a go. Can you suggest a good product? I've
looked at Dryzone, which looks fairly easy - is it possible to hire the
injection gun or should I just buy one?

Wooden battens wouldn't last long on the wet side of the barrier.

Even if they were tanalised?

I suppose you could use plastic and stainless steel fixings, but I
wouldn't embark on anything that drastic before trying other options.
You'd be losing space and would have to line up the new surface with
windows and doors somehow.

I don't mind losing a couple of inches or so as it's a fairly big room
anyway. I can work around the door and window without too much fuss.

I know of one property round here where foil faced plasterboard was
slapped directly on to damp brickwork during "renovation". The internal
walls still look good 5-6 years later, so I guess they got away with it.

Would you agree that if it *IS* condensation then drylining would
probably improve matters. If it's rising damp then the injected DPC
would would offer the best bet, and drylining as well won't hurt.

Bodgit wrote:
In that case maybe all the walls should be injected. Better to do that
yourself to ensure the right amount of fluid is used (I don't trust
contractors). Damp on the lower part of an internal wall strongly
suggests that it's rising, and this would be a low cost first step.

I'm prepared to give it a go. Can you suggest a good product? I've
looked at Dryzone, which looks fairly easy - is it possible to hire the
injection gun or should I just buy one?

Dryzone only needs a mastic type applicator but I have my doubts about
it. The idea that the moisture in the wall magically disperses the cream
in all directions sounds a bit like wishful thinking to me, but at least
it wouldn't cost much to try. I'd rather rely on the traditional pump
method. Hire it for a weekend and take your time. As it says on the
Dryzone site, the disadvantages are that it takes longer to apply and
longer to dry out, neither of which should be a problem with d-i-y


Wooden battens wouldn't last long on the wet side of the barrier.

Even if they were tanalised?

Even then


I suppose you could use plastic and stainless steel fixings, but I
wouldn't embark on anything that drastic before trying other options.
You'd be losing space and would have to line up the new surface with
windows and doors somehow.

I don't mind losing a couple of inches or so as it's a fairly big room
anyway. I can work around the door and window without too much fuss.

I'm just wary of drastic measures that seem like they should work
logically. I'd rather confirm the cause before discussing the remedies.
See below


I know of one property round here where foil faced plasterboard was
slapped directly on to damp brickwork during "renovation". The internal
walls still look good 5-6 years later, so I guess they got away with it.

Would you agree that if it *IS* condensation then drylining would
probably improve matters. If it's rising damp then the injected DPC
would would offer the best bet, and drylining as well won't hurt.

There are simple tests for condensation. E.g. fix a mirror to the wall
and see if it mists up a) with the room heated normally and b) overnight
with the heating off. I had a similar situation in one of our rooms a
few years back that had a framed mirror sitting tight against an outside
wall. The hardboard backing was always dotted with mildew but never any
sign of moisture on the glass. Probably not a foolproof test, but pretty
close.
The other thing I'd do is contact a few local builders. Pick their brains

Bodgit wrote in message
oups.com...
The problem (sorry it's a bit long):

Moved into our 150 year old house (soft brick and no DPC) a year and a
half ago. I knew there were some damp issues and I've addressed some in
other parts of the house,
snip
The ceiling (and floor of room above) is made from 14" thick reinforced
concrete.

From your description I think you have more a problem with condensation then
rising damp however,
If it really is rising damp

Dry lining cellar walls with plasterboard, that has a concrete floor and
ceiling just will not work.
You will get condensation forming behind the plasterboard with no escape
route
Tanking is really the only sensible option in this situation if you want to
use it as a modern habitable room.
a limewash loony will be along shortly to advise digging a French ditch and
letting the walls breath.


-

Dry lining cellar walls with plasterboard, that has a concrete floor and
ceiling just will not work.
You will get condensation forming behind the plasterboard with no escape
route

Would a plastic membrane directly behind the plasterboard not be a
solution?

Tanking is really the only sensible option in this situation if you want to
use it as a modern habitable room.
a limewash loony will be along shortly to advise digging a French ditch and
letting the walls breath.

We don't have a problem with the floor - just the walls. It might sound
stupid but Is it possible to to just tank the walls?