Occasional Damp Patches on Inside Wall - who can help?

[glpcboat]

We have an ongoing problem that we have been trying to resolve for a couple of years.

We have two damp patches that appear on an inside wall between our kitchen & dining room - only 3-4 times a month and generally we only notice this in the summer! They are about 1ft square or less each, but always in the same place. It seems that they appear shortly after rain - some times but not always - but never when it is dry weather. There are no marks once the patch has dried, so no salty deposits or mould, just seems like 'clean water' patches. I am therefore, not sure if these are rising damp or a leak from somewhere else. The outside walls appear all completely dry - don't show any damp patches at all.

We are just getting no-where and need an independent expert to help us identify where this is coming from before we spend any more money.

What type of professional would best assist with identifying the source of this? I thought maybe a building surveyor? and if so, can anyone recommend anyone in Worcestershire. I don't want to get in a damp finding company as I really want an independent expert to help us resolve this once and for all. Any suggestions would appreciated. Thank you,

 

[TheVictorian]

What is the internal wall made of? Could it be a cold spot that gets damp when the level of humidity is high?

A photo would probably help.

 

[glpcboat]

What is the internal wall made of? Could it be a cold spot that gets damp when the level of humidity is high?

A photo would probably help.

The damp patches are either side of an internal wall 'archway'. One side is a false wall (plasterboard both sides with 6-8 gap inbetween) the other side is solid brick with plaster covering it. Both internal walls. All outside walls appear dry. The picture was taken last year when we took everything apart - and replaced the floor and all the central heating pipes, and even put a piece of plastic into the wooden strut on the left to stop any damp from rising. The problem is exactly the same now as it was then! (I hope I have enclosed the photo OK but will try again if not!).
Picture 1) is general showing both sides of the arch - it is wet on the right side of the arch but not as bad, but not sure if you can see it on the photo
Picture 2) - from the kitchen side (this side does not appear damp) - but shows the structure of the wall. We put the plastic piece in between the wood to stop the water rising, but since this has not stopped it - maybe it is not rising after all!
Picture 3) Close up of the one side of the arch.
Picture 4) Gives a general view of the dining room with arch and the water leaks are both sides of the arch at the bottom.

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• glpcboat
• 19 Aug 2013
• 1

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• glpcboat
• 19 Aug 2013
• 1

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• glpcboat
• 19 Aug 2013
• 1

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• glpcboat
• 19 Aug 2013
• 1

Background info: House built 1930 with several extensions added. The central heating pipes run along the floor in this area, but all dug up and replaced. The dining room side (wallpaper side) adjacent floor quarry tiles dug out and replaced with new concrete floor (not wet underneath anyway) with membrane etc. All pipes within 15 feet replaced. Other factors: we have underground drain system but CCTV survey said all reasonable order (ceramic pipes) but walls don't get damp when we used house drains normally. Chimney 10 feet away, stack of 3, only 1 used, other 2 not used but not capped off either. Bathroom nearly above, but have taken up carpet/floorboards - no evident leaks. Water tank in loft, changed (one small leak found 2 years ago, but nothing more since). New land drain added to front of house..... we have been trying but running out of ideas now!

 

[dann09]

On the LH wall paper side, the studs/posts are not set on a plate, & appear to go below the concrete into the, presumably, sub-soil.
They might be pulling up some moisture. Which would account for the "tide marks" on the wall paper.

Something similar might be taking place on the brickwork side of the arch.

The laminated side floor doesn't appear to have a membrane?
I dont quite understand when you say you have inserted a little bit of membrane - where do i see it?

If you post any more pics please clear away all debris etc. and give a clear view of both concrete floor surfaces

 

[glpcboat]

On the LH wall paper side, the studs/posts are not set on a plate, & appear to go below the concrete into the, presumably, sub-soil.
They might be pulling up some moisture. Which would account for the "tide marks" on the wall paper.

Something similar might be taking place on the brickwork side of the arch.

The laminated side floor doesn't appear to have a membrane?
I dont quite understand when you say you have inserted a little bit of membrane - where do i see it?

If you post any more pics please clear away all debris etc. and give a clear view of both concrete floor surfaces

Thank you for your reply. The pictures here were taken last year when we had everything apart and we thought we had resolved this. it is all fully restored currently but the water marks are still appearing.

The wooden stud/posts - seem to have been built on top of one of the original brick walls of the house. They did not appear to go into the soils when we excavated the area.

The laminated floor side (kitchen) is a later extension and this it is a concrete floor about 8 inches deep and it does have a membrane underneath it which we found when we were replacing all the central heating pipes.

The second picture (blue walls) shows a close up of the wall structure as best as I can show it now, as it has been re plastered over now. Hopefully if you look closely at the wooden upright strut - we cut through the timber and inserted a piece of plastic horizontally that was intended to stop any moisture rising up the wooden strut. But this has not stopped the moisture problem - which still appears exactly as before.

Hope this explains more, thank you, Gail

 

[dann09]

If you were able to cut and slide a piece of damp into a bearing stud/post, then that stud had very little load on it, so, presumably, the partition is not load bearing.
FWIW, your remedial measure is almost worthless.

The root cause, i would suggest, is capillary action (rising damp) from the old, below the concrete, brickwork.
Partition/studwork bottom plates should sit on the concrete surface not go below it.

Whoever originally built the partition and/or poured the floors should have been alert to this capillary possibility.

One remedial option would be to sand and lime and cement, semi-tank the walls to a height of 1m. This would give you a 20 year damp/stain free breathing space - however, decay would continue in the walls to any wood members.

Another option would be to open it all up, & cut out all below concrete FFL, make good & rebuild a new, say, 1m high frame.

 

[mattice]

We've got an identical issue. Concrete slab where once existed floor on earth, walls left with original footings, seepage occurring from outside capillary action under concrete and membrane, hitting internal wall and sucking it up like a sponge. Internal wall is solid brick but with infilled wood frame, a previous attempt at chemical damp course, tanking and a layer of cement render which has failed to prevent problem materialising (by previous owner)

Exactly same symptoms as yours, external walls fine, only one internal. I've sorted out ground levels with a small evaporation gully around the outside walls to discourage water from hitting underneath of concrete slab and wicking through. It's reduced the size of the damp patch in heavy rain but not solved it. Next measure is a french drain to intercept water coming down the slope towards the house. Note this isn't surface water, that's dealt with, I'm guessing from my excavations there's a movement of water underneath my tarmac drive... could be wrong.

If that doesn't work, I'm going to strip back concrete render, membrane, bad material, and then lime plaster and let it breath and evaporate. Don't think we can stretch to a physical damp course. I think we don't see it in winter because the heating/log burner evaporates it off relatively quickly.

Interestingly I think my mains water has a junction near this wall so I suspect the rain water is making its away the path of this pipe buried in the concrete floor, hence trying to get some moisture out of the ground with the french drain.

 

[glpcboat]

If you were able to cut and slide a piece of damp into a bearing stud/post, then that stud had very little load on it, so, presumably, the partition is not load bearing.
FWIW, your remedial measure is almost worthless.

The root cause, i would suggest, is capillary action (rising damp) from the old, below the concrete, brickwork.
Partition/studwork bottom plates should sit on the concrete surface not go below it.

Whoever originally built the partition and/or poured the floors should have been alert to this capillary possibility.

One remedial option would be to sand and lime and cement, semi-tank the walls to a height of 1m. This would give you a 20 year damp/stain free breathing space - however, decay would continue in the walls to any wood members.

Another option would be to open it all up, & cut out all below concrete FFL, make good & rebuild a new, say, 1m high frame.

Thank you for your reply. The trouble with these older properties is that you don't know what's underneath etc., until you dig it all up. There are no real patterns with these patches appearing - they can appear 'at the same time' as some very light rain and then won't appear after a downpour for a day. It hasn't appeared during long spells of dry weather.

We have an old drain network in the vicinity of this area (those ceramic type pipes) and we did have a CCTV survey done which showed they were not perfect but still intact/OK. BUT we don't see the damp patches appearing when we are 'at home' using all the services (dishwasher, washing machine, kitchen sink, downstairs bathroom).

Last year we replaced the patio at the back of the house - outside of pic 4 above - and put in slate barrier and membrane to about 20" deep to the exterior brickwork, also gave us a chance to see if any old pipework in the area but nothing much found. It didn't 'look/feel' particularly wet soil at a depth outside / under the patio, but I realise this can be deceptive.

Thanks for the info on what we could do next. If you are saying it definitely looks like water from below - before we embark on taking the wall apart - do you think a land drain directly outside might work or not? Just the thought of building work again in the middle of the house doesn't fill me with the joys of spring! Thank you, Gail

 

[dann09]

It might pay you, in the long run, to engage an independent damp surveyor such as: G.R. Coleman or Patrick Doyle.
I'm merely using them as examples of independent surveyors.

Ground water from wherever, or the water table on sloping land, might be contributing to your difficulties, but that call is an on site view and judgement.

Testing drains is a simple, well established procedure - no cameras etc necessary.

You refer to a puzzling "slate barrier and membrane" - this too calls for an on site view.

Sorry that i'm not much help.