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Clive Long,UK
 
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Default "Damp" internal wall - initial measurements made. Any ideas?

"Damp" (condensation?) wall

Hello,

A brief description. The lower part of an internal wall in a purpose
built flat is suffering from "damp". The wall paper has lifted way.
there is no mould growth.

Now I have borrowed a Protimeter (damp meter) from a surveyor friend
, taken about 100 readings and I am reading the excellent "Dampness in
Building" Oxley / Gobert ISBM 0-7506-2059-5.

To summarise what I have found.

The wall is 7.60m long, 2.35m high. It is a "shared" (with adjacent
flat) internal wall, probably load bearing as concrete lintels cross
it at right angles. The composition is (probably) brieze block with a
plaster skim (as in rest of flat). There is a soft-wood, 9cm skirting
and the floors are solid concrete skim with vinyl tiles. On top of the
tiles is Dunlop underlay and wool/nylon carpet.

Left-Hand end of the wall is adjacent to the front door that opens to
an internal hallway in the block, not directly outside. Right-hand end
of the wall is adjacent to, and at right-angles to, another internal
wall that is tiled bathroom wall on the other side.

I have taken "damp" readings at 25cm horizontal intervals and 10cm
vertical intervals (what a tedious job !!).

Results: At LH end by front door, the skirting and wall register
between 11 to 13 – this is not a concern to me.

One third of the way from the RH end, opposite a large
double-panelled radiator the damp registers as follows.

The skirting measures between 17 to 24. The skirting is more damp the
closer the reading is made to the junction with the floor.

The wall immediately above the skirting measures between 20 to 50.
The highest wall reading occurs directly above the highest skirting
reading.
Question: Could the high conductance be due to damp wall-paper rather
than the plaster?

The damp reading diminishes rapidly vertically to a level of 12 to 14
at a height of 30 cm. This value is for any position along the wall,
including the most damp areas just above the skirting toward RH end

At any height above 30cms the wall measures 12 or 13.

Initial thoughts

1. The radiator is causing the problem. But how? And what to do? I
can't move the rad.
2. Damp is coming from the floor. How do I investigate that further?

Any ideas on what to investigate next to try to isolate the problem
before I call someone in who may attempt the wrong treatment because
they haven't understood the cause ?

Many thanks

Clive
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John Rumm
 
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Default "Damp" internal wall - initial measurements made. Any ideas?

Clive Long,UK wrote:

To summarise what I have found.

The wall is 7.60m long, 2.35m high. It is a "shared" (with adjacent
flat) internal wall, probably load bearing as concrete lintels cross


Do you know what is the other side of the wall? (for example a bathroom,
a radiator, aquarium ;-) ?

The skirting measures between 17 to 24. The skirting is more damp the
closer the reading is made to the junction with the floor.

The wall immediately above the skirting measures between 20 to 50.
The highest wall reading occurs directly above the highest skirting
reading.
Question: Could the high conductance be due to damp wall-paper rather
than the plaster?


Well it can be - those meters can be rather notorious for measuring all
sorts of unexpected things if you don't pay attention to how you are
using it (i.e. conductive wallpaper, surface moisture, cinder block
(i.e. high carbon) wall construction). They were originally designed for
making measurements in timber - for which they are quite accurate -
hence your comment about a high moisture content on the skirting would
seem to indicate more than just surface moisture.

Initial thoughts

1. The radiator is causing the problem. But how? And what to do? I
can't move the rad.


The radiator itself may not be a problem - you would probably see water
dripping / spraying out if it was leaking - possibly even rusty water
stains, but where do the pipes go?

For example, a set of pipes buried in the concrete floor can be a soggy
mess waiting to happen if the pipes were not adequately protected before
being concreted over.

2. Damp is coming from the floor. How do I investigate that further?


Short of drilling a hole and analysing the water content of the dust
removed by the drill - tricky.

Any ideas on what to investigate next to try to isolate the problem
before I call someone in who may attempt the wrong treatment because
they haven't understood the cause ?


Look for the obvious causes first. So called "rising damp" is very rare
in reality - almost unheard of in modern building materials. Penetrating
dampness from the other side of the wall is far more likely. So check
that with the neighbour (also finding out if they have the same problem
(or a less or more severe version of it) would help. See if you can
trace where the radiator pipes go as well.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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Clive Long,UK
 
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Default "Damp" internal wall - initial measurements made. Any ideas?

John / All

My responses are in-line

John Rumm wrote in message ...
Clive Long,UK wrote:

To summarise what I have found.

The wall is 7.60m long, 2.35m high. It is a "shared" (with adjacent
flat) internal wall, probably load bearing as concrete lintels cross


Do you know what is the other side of the wall? (for example a bathroom,
a radiator, aquarium ;-) ?


On the other side is another narrow hallway with no furniture nor
radiator. The flats are "mirror image".


Question: Could the high conductance be due to damp wall-paper rather
than the plaster?


Well it can be - those meters can be rather notorious for measuring all
sorts of unexpected things if you don't pay attention to how you are
using it (i.e. conductive wallpaper, surface moisture, cinder block
(i.e. high carbon) wall construction). They were originally designed for
making measurements in timber - for which they are quite accurate -
hence your comment about a high moisture content on the skirting would
seem to indicate more than just surface moisture.


Well the wall I think is this "high carbon" material covered with
plaster skim. When I have drilled into it in the past it is a black
material that disintegrates when assaulted by a hammer drill. However,
the depth I am pushing in the probes of the Protimeter make me feel I
am only measuring conductance through damp plaster.



Initial thoughts

1. The radiator is causing the problem. But how? And what to do? I
can't move the rad.


The radiator itself may not be a problem - you would probably see water
dripping / spraying out if it was leaking - possibly even rusty water
stains, but where do the pipes go?

For example, a set of pipes buried in the concrete floor can be a soggy
mess waiting to happen if the pipes were not adequately protected before
being concreted over.


The radiator is on the OPPOSITE wall to where the damp is - I did not
make this clear. Also all pipes are "surface mounted" on the skirting
and not leaking.
The reason I mentioned the radiator is that the Oxley book gives a
scenario where hot "moist" air from a radiator rises then moves across
the ceiling, cools, drops down the opposite wall, cools more until the
wall temperature is dew point and the moisture in the air condenses
into the porous plaster.


2. Damp is coming from the floor. How do I investigate that further?



Short of drilling a hole and analysing the water content of the dust
removed by the drill - tricky.


But maybe if I lift the carpet and underlay, and some vinyl tiles. If
there is an obvious source of damp the underlay should be damp at this
point - and I can try to measure the dampness of the concrete screed.
Thoughts ???


Any ideas on what to investigate next to try to isolate the problem
before I call someone in who may attempt the wrong treatment because
they haven't understood the cause ?


Look for the obvious causes first. So called "rising damp" is very rare
in reality - almost unheard of in modern building materials. Penetrating
dampness from the other side of the wall is far more likely. So check
that with the neighbour (also finding out if they have the same problem
(or a less or more severe version of it) would help. See if you can
trace where the radiator pipes go as well.


I have tried getting access to the neighbours property on 3 occasions.
He just says he doesn't have a damp problem and won't let me in to
measure. There are other issues around not getting access not related
to investigating damp. If I can get a solution to the "damp /
condensation" problem that then puts him in a position where he has to
be more co-operative - then that will be a satisfactory outcome. I
won't do anything that will deliberately cause a problem for him.

As mentioned above, routing of radiator pipes is not an issue as they
are all surface mounted.

I'm happy to pay a professional to cure the problem - but I need it
properly diagnosed. I get the impression that a lot of the
"Professionals" are quite the opposite - which is why I am performing
the initial investigation myself and I will be in a better position to
ask "why?".

--
Cheers,

John.

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Lee Blaver
 
Posts: n/a
Default "Damp" internal wall - initial measurements made. Any ideas?

Clive Long,UK wrote:
snip

I have tried getting access to the neighbours property on 3 occasions.
He just says he doesn't have a damp problem and won't let me in to
measure.


Ask the freeholder to take a look? Unless you are in scotland...

I won't do anything that will deliberately cause a problem for him.


Well that might negate asking the freeholder then

Lee

--
To reply use lee.blaver and ntlworld.com
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John Rumm
 
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Default "Damp" internal wall - initial measurements made. Any ideas?

Clive Long,UK wrote:

Do you know what is the other side of the wall? (for example a bathroom,
a radiator, aquarium ;-) ?


On the other side is another narrow hallway with no furniture nor
radiator. The flats are "mirror image".


Oh well that eliminates some possibilities...

Well the wall I think is this "high carbon" material covered with
plaster skim. When I have drilled into it in the past it is a black
material that disintegrates when assaulted by a hammer drill. However,
the depth I am pushing in the probes of the Protimeter make me feel I
am only measuring conductance through damp plaster.


If the plaster is dry then they would be unlikely to make much
difference - however they will tend to make a slightly damp wall look
more damp than it is - think of the plaster as a medium value resistor
and the cinder block as a low value one wired in parallel with it.

The radiator is on the OPPOSITE wall to where the damp is - I did not
make this clear. Also all pipes are "surface mounted" on the skirting
and not leaking.


OK not that then

The reason I mentioned the radiator is that the Oxley book gives a
scenario where hot "moist" air from a radiator rises then moves across
the ceiling, cools, drops down the opposite wall, cools more until the
wall temperature is dew point and the moisture in the air condenses
into the porous plaster.


Would have to be in quite a damp environment I would have thought - if
the whole room is heated then the amount of dampness in the air to
circulate should not be that high unless there is an unventilated
adjacent shower room that is adding lots of moisture to the air.

But maybe if I lift the carpet and underlay, and some vinyl tiles. If
there is an obvious source of damp the underlay should be damp at this
point - and I can try to measure the dampness of the concrete screed.
Thoughts ???


May be worth doing... How far are you from "outside" at this point in
the building?

Some flooring materials (like the lime putty based stuff the use in some
places) can be quite hygroscopic - sucking water up from adjacent sources.

I have tried getting access to the neighbours property on 3 occasions.
He just says he doesn't have a damp problem and won't let me in to
measure. There are other issues around not getting access not related
to investigating damp. If I can get a solution to the "damp /
condensation" problem that then puts him in a position where he has to
be more co-operative - then that will be a satisfactory outcome. I
won't do anything that will deliberately cause a problem for him.

As mentioned above, routing of radiator pipes is not an issue as they
are all surface mounted.

I'm happy to pay a professional to cure the problem - but I need it
properly diagnosed. I get the impression that a lot of the
"Professionals" are quite the opposite - which is why I am performing
the initial investigation myself and I will be in a better position to
ask "why?".


I also suspect that many so called damp proofing "specialists" are
nothing of the sort - the whole industry seems to be somewhat
questionable in many cases (aided and abetted by the mortgage lenders /
surveyors as well!)

It strikes me that this would be an easy job to end up "fixing" without
ever finding the actual cause. This would only tend to hide the problem
though. For example the usual damp proofing company fix of hacking off
the plaster and replacing it with render containing a good amount of PVA
then skimming over, and pressure injecting a DPC along the base of the
wall would keep your side of the wall dry - might make the problem worse
(if there is one) on the other side though. If the problem really was
condensation then this could make your problem worse.

Nothing to stop you getting a few of the "damp experts" to give you
their view / estimate - you never know you may find one that knows what
they are doing.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/


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Meoww
 
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Default "Damp" internal wall - initial measurements made. Any ideas?

(Clive Long,UK) wrote in message om...
"Damp" (condensation?) wall

Hello,

A brief description. The lower part of an internal wall in a purpose
built flat is suffering from "damp". The wall paper has lifted way.
there is no mould growth.

Now I have borrowed a Protimeter (damp meter) from a surveyor friend
, taken about 100 readings and I am reading the excellent "Dampness in
Building" Oxley / Gobert ISBM 0-7506-2059-5.

snip

Initial thoughts

1. The radiator is causing the problem. But how? And what to do? I
can't move the rad.
2. Damp is coming from the floor. How do I investigate that further?

Any ideas on what to investigate next to try to isolate the problem
before I call someone in who may attempt the wrong treatment because
they haven't understood the cause ?

Many thanks

Clive



Presumably the flat is modern?

Does this problem occur all year round or is it just in the colder
months?

Is it causing degradation of the decorations?

If you're reading oxley, you'll know that rising damp will give a
reading showing a rapid cut off approximately one metre above the
floor level, is this what it's doing?

I had a very similar problem a few years ago in an end terrace. The
wet wall was a gable wall at the bottom of the stairs. Next to the
bulding and separated from the gable wall by no more than nine inches
was another building. This ruled out penetrating damp because the
wall was protected and rising damp wasn't an issue because there was a
basement and this wasn't damp. I finally figured out that the gable
wall in question was being ultra cooled by the draught blowing through
the gap between the two buildings and, because there was a radiator at
the bottom of the stairs, this was causing severe condensation. Double
glazing compounded the problem of course and in the end we moved the
radiator.

You say that next to your problem wall, in next door's flat, is a
corridor without a radiator. It's a posibility that this too is a
very cool area and your wall is consequently losing heat to it and
becoming an ideal condensing surface.

If this only happens in the colder months then condensation is your
prime suspect! However, if the moisture content of the skirting is
above 18 percent wme then it's in danger of rotting.

Patick
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