I have a room with three walls which are to varying degrees below ground level. (1960's split level house). These walls have a corrugated type waterproofing below the plaster and the floor has a plastic sheet which comes up at the walls going behind the corrugated sheets. This all seems OK but there is a wardrobe sized alcove that doesn't seem to have any damp proofing. On moving in 18 months ago I ripped out the previous owners wooden panels and shelves to find a lot of damp. I left this to dry out to get on with other jobs and now want to address the problem. It has reduced to a handfull of damp patches that come and go depending on the weather. Do I seal with Thomsons, paint with bitumen, do both or do nothing to the walls. I want to fit pasterboards (perhaps with air vents) on battens and use it as a wardrobe.
Penetrating Damp
- Thread starter floss_4
- Start date
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Could you tell me what is on the other side of this particular bit of damp wall. Also is there black mould present or just damp patches or both?
Also is the wall insulated and is it possible that the cavity needs cleaning ?
Also is the wall insulated and is it possible that the cavity needs cleaning ?
The other side of this wall is ground right the way up. The house is built on a slope - this is the back of the lower floor which is below ground level at this point. It is therefore not possible to get to the otherside of this wall without major excavations and path/steps removal. It is not possible to tell if the cavity has debris without major work. I dug down a bit below floor level. I could not find a DPC but soon found damp earth beneath the concrete floor. I think this room was just a void/cellar in the original build and the previous owner converted it for bedroom use. This seems to have been a success except this alcove. There is no black mould.
My thoughts are
Tank the area (but risk pushing the damp to the edges of the tank)
Inject a DPC around the alcove (is there a DIY kit for this?)
Dry line with some ventilation to let the damp come and go behind
My thoughts are
Tank the area (but risk pushing the damp to the edges of the tank)
Inject a DPC around the alcove (is there a DIY kit for this?)
Dry line with some ventilation to let the damp come and go behind
Things that will help - The more you do of these the merrier: -
Checking for water coming from leaking gutters, overflows, combi pressure relief valves, drains etc
Fitting ground drainage outside to reduce moisture in the soil around your building
Making sure the cavity is clean.
Fitting air bricks to help vent moisture from the cavity
Splashing thompsons water seal all over the place
Painting inside with bitumen
Checking your existing dpm [plastic sheet] and repairing any breaches
Not sure about your dry lining idea as when you nail the battens you will be putting holes in the very thing that is holding the moisture back. Is it possible to build a framed wall without touching the damp wall, fixing between floor and ceiling perhaps. Try some of the above ideas first and see how it goes.
I'm not sure about Injection if your wall happens to be breeze block, you will have to see a specialist for that one. If its brick then it will be advantageous but suggest that you get a firm to do it that will give you a guarantee.
Checking for water coming from leaking gutters, overflows, combi pressure relief valves, drains etc
Fitting ground drainage outside to reduce moisture in the soil around your building
Making sure the cavity is clean.
Fitting air bricks to help vent moisture from the cavity
Splashing thompsons water seal all over the place
Painting inside with bitumen
Checking your existing dpm [plastic sheet] and repairing any breaches
Not sure about your dry lining idea as when you nail the battens you will be putting holes in the very thing that is holding the moisture back. Is it possible to build a framed wall without touching the damp wall, fixing between floor and ceiling perhaps. Try some of the above ideas first and see how it goes.
I'm not sure about Injection if your wall happens to be breeze block, you will have to see a specialist for that one. If its brick then it will be advantageous but suggest that you get a firm to do it that will give you a guarantee.
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I assume that the 3no walls are exterior walls and that this room is essentially a cellar.
With respect to Slugbaby, do not use any water sealant either inside or outside.
Do not use bitumen paint either.
Do not inject any DPC chemicals.
If the majority of the walls except for the alcove have been tanked with "corrugated" materials and rendered over then the best remedial method would be to hack off the render in the alcove to the brickwork and tie in an area of local tanking and then render to matchup.
This would be a tricky matter so perhaps to start you would be better to carefully remove a little of the plaster/render in the alcove to determine exactly what conditions pertain, then report back here.
I'm not clear as to wether your floor has a membrane or not?
How do you know if partial tanking has taken place? It's usual for a written guarantee or even a disclaimer to be issued after tanking work - where is it? Did the property have a DPC report on sale?
With respect to Slugbaby, do not use any water sealant either inside or outside.
Do not use bitumen paint either.
Do not inject any DPC chemicals.
If the majority of the walls except for the alcove have been tanked with "corrugated" materials and rendered over then the best remedial method would be to hack off the render in the alcove to the brickwork and tie in an area of local tanking and then render to matchup.
This would be a tricky matter so perhaps to start you would be better to carefully remove a little of the plaster/render in the alcove to determine exactly what conditions pertain, then report back here.
I'm not clear as to wether your floor has a membrane or not?
How do you know if partial tanking has taken place? It's usual for a written guarantee or even a disclaimer to be issued after tanking work - where is it? Did the property have a DPC report on sale?
When I looked at the question I assumed a worst case scenario of construction when I saw this.floss_4 said:
As we are aware that is the problem with not being able to look at a job on here. I post on here to try to help people as most do but am aware that I too can always learn something. I wonder if you could explain about the water sealant and injection not being of any use or as you infer being detrimental. I can see your point about the bitumen though as it can hold water behind its surface and it is a poor substitute for proper asphalt tanking.tim00 said:
Thanks for the usefull tips.
I have removed the plaster/render in the alcove - there is no tanking. The floor has a membrane which goes into the alcove and stops about 6 inches from the wall - the damp starts in the concrete the other side of this membrane and goes a few inches up the wall. (when the previous owner boarded up this area the damp went much higher and ruined the plaster).
I know tanking has been carried out in the rest of the room as it is visible at the bottom when the skirting is removed.
The surveyor picked up condensation damp in this room but wouldn't have seen this current problem as it was covered up by the previous owners wooden cupboard/panelling.
I am tempted to further dig out the 6 inches of concrete floor that is outside of the membrane and see if there is a DPC further down.
I have removed the plaster/render in the alcove - there is no tanking. The floor has a membrane which goes into the alcove and stops about 6 inches from the wall - the damp starts in the concrete the other side of this membrane and goes a few inches up the wall. (when the previous owner boarded up this area the damp went much higher and ruined the plaster).
I know tanking has been carried out in the rest of the room as it is visible at the bottom when the skirting is removed.
The surveyor picked up condensation damp in this room but wouldn't have seen this current problem as it was covered up by the previous owners wooden cupboard/panelling.
I am tempted to further dig out the 6 inches of concrete floor that is outside of the membrane and see if there is a DPC further down.
Slug,
1. water sealant: it can create a barrier (when it works) that moves the problem higher or sideways. Often it creates a mosaic confusing effect. It is useless against penetrating ground water. It also stops the wall from "breathing"
2. With raised ground levels at what height are you going to install the injected DPC? Dpc chemicals can dissolve a perfectly good bitumen Damp course. It can also degrade any tanking or membrane esp. at the seals. And in my experience injection simply does not work.
3. Both above chemicals can involve high flammability risks.
Floss,
1. Dont touch the concrete floor slab.
2. Expose all areas, floor and wall that are not "tanked"
3. Now attempt to patch in new tanking /membrane.
4. What exactly did the report say about the damp/condensation?
5. Where is the tanking guarantee/warranty?
6. Is there adequate ventilation in the room?
1. water sealant: it can create a barrier (when it works) that moves the problem higher or sideways. Often it creates a mosaic confusing effect. It is useless against penetrating ground water. It also stops the wall from "breathing"
2. With raised ground levels at what height are you going to install the injected DPC? Dpc chemicals can dissolve a perfectly good bitumen Damp course. It can also degrade any tanking or membrane esp. at the seals. And in my experience injection simply does not work.
3. Both above chemicals can involve high flammability risks.
Floss,
1. Dont touch the concrete floor slab.
2. Expose all areas, floor and wall that are not "tanked"
3. Now attempt to patch in new tanking /membrane.
4. What exactly did the report say about the damp/condensation?
5. Where is the tanking guarantee/warranty?
6. Is there adequate ventilation in the room?
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