I am about to take the plaster off a wall in my convertion, it is literally just falling off at the moment. I was going to just dab and dob new plasterboard up but it appears to have a Damp Proof membrane underneath it. I have no idea why it is there as the wall already has a damp course, but it must be up there for a reason. Can anyone advise me what I should use to replace this old damp proof membrane? and how to go about putting plasterboard over the top of it. would a liquid damp proof membrane do the trick? I am also having issues with uneven joists for the ceiling so I figure its best to get this wall fixed before I level the joists. Any advise much appreciated
Damp Proof membrane
- Thread starter Blunda
- Start date
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what is the wall construction?
is it retaining any soil externally?
are there timber battens present - therefore some kind of vapour barrier?
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it is normal practice to deal with the ceiling before the walls, but i guess as long as you skim the ceiling first then nae bother.
just make sure you have adequate ceiling joist width available for fixing to, as joists that are tight against the wall may have little thickness left, once the wall boards have been fitted.
is it retaining any soil externally?
are there timber battens present - therefore some kind of vapour barrier?
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it is normal practice to deal with the ceiling before the walls, but i guess as long as you skim the ceiling first then nae bother.
just make sure you have adequate ceiling joist width available for fixing to, as joists that are tight against the wall may have little thickness left, once the wall boards have been fitted.
In all homes the indoors humidity is higher than outdoors.
Water vapour from our breathing and sweating moves through the air into/on the nearest cold thing, usually a cold window but, equally a cold wall will do.
Someone has fitted an almost water vapour proof membrane just under the surface of the wall to stop this outgoing humidity.
Have the other outside walls and the ceiling been done as well?
Humidity/water vapour being lighter than air usually rises and escapes through the ceiling, all plasterboard is transparent to water vapour and it has no problem in passing through.
Water vapour from our breathing and sweating moves through the air into/on the nearest cold thing, usually a cold window but, equally a cold wall will do.
Someone has fitted an almost water vapour proof membrane just under the surface of the wall to stop this outgoing humidity.
Have the other outside walls and the ceiling been done as well?
Humidity/water vapour being lighter than air usually rises and escapes through the ceiling, all plasterboard is transparent to water vapour and it has no problem in passing through.
none of the other walls appear to have it just this one. It appears the dpm comes from underneath the concrete floor aswell. It is a very old DPM, it appears to be made of bitumen and is corrugated. There was no evidence of damp before I ripped the plaster off and I was wondering if i could get away with just screwing some batons to the old DPM and screw plasterboard to the batons without replacing the DPM?
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You can but, if you can I would suggest waiting a few days until we have had some heavy rain, then check the wall with a damp meter. If its reading OK, then go ahead.
Almost a month has passed since your first post, so I imagine that the wall is dry, therefore just cut the old dpm off.
Do consider using wet plaster, as plasterboard can act as a refrigerator if there are holes in the wall, cold air can circulate behind the boards and make the room cold.
Do consider using wet plaster, as plasterboard can act as a refrigerator if there are holes in the wall, cold air can circulate behind the boards and make the room cold.
I haven't yet decide to wet plaster or batten out plasterboard but if i was to go the plasterboard route would this possibly help with stopping the plasterboard getting cold?
http://www.wickes.co.uk/FOIL-INSULATION/Thermal-Insulation-Foil-Roll/invt/210022
http://www.wickes.co.uk/FOIL-INSULATION/Thermal-Insulation-Foil-Roll/invt/210022
I have never used that product, so cannot comment.
What I would recommend is a combined PIR Thermal Insulation from Celotex PL3000, this will stop around 90% of your heat going through the walls. Take a look, the other stuff is merely aluminium foil with a very thin polystyrene backing.
What I would recommend is a combined PIR Thermal Insulation from Celotex PL3000, this will stop around 90% of your heat going through the walls. Take a look, the other stuff is merely aluminium foil with a very thin polystyrene backing.
Fantastic! thanks for your help I will get that plasterboard, thanks.
I have done a little research on this plasterboard and I read they come with a vapour barrier, what i was wondeing is if it does come with a vapour barrier, will i still need to put my DPM up if the wall is damp?
I have done a little research on this plasterboard and I read they come with a vapour barrier, what i was wondeing is if it does come with a vapour barrier, will i still need to put my DPM up if the wall is damp?
If your wall is damp, you need to batten out on the wall and fix your insulated plasterboard onto the battens. This should allow any condensation forming on the vapour barrier to have the opportunity to evaporate.
If you wall is constantly damp on the internal side, you may need to get this checked out as this will eventually work its way to your other walls and may cause long term damage. Try to identify where the moisture ingress is happening and treat the area.
If you wall is constantly damp on the internal side, you may need to get this checked out as this will eventually work its way to your other walls and may cause long term damage. Try to identify where the moisture ingress is happening and treat the area.
I had hoped that you had resolved the question of, is the wall damp, as it is almost a month since your first enquiry.
If the wall is damp, you need to find out why.
If there is a problem with the damp course, then the damp will rise to about 4 feet from ground level. Take a look outside and measure up the wall, check that the ground outside is well below the damp proof course, ie; preferably below by more than 9 inches.
If the wall is damp higher than 4 feet, you may find that rain is coming through the outer skin, moving through the wall, in which case the whole wall may be damp.
Finally you may have a leaking roof or gutter or pipe.
So which is it?
If the wall is damp, you need to find out why.
If there is a problem with the damp course, then the damp will rise to about 4 feet from ground level. Take a look outside and measure up the wall, check that the ground outside is well below the damp proof course, ie; preferably below by more than 9 inches.
If the wall is damp higher than 4 feet, you may find that rain is coming through the outer skin, moving through the wall, in which case the whole wall may be damp.
Finally you may have a leaking roof or gutter or pipe.
So which is it?
PerryOne - I have yet to test for damp and am thinking of worse case scenario, I will be getting a damp tester today to see for sure.
Etienne247 - will I need fit vertical and horizontal battens or just horizontal? Plus am I able to use regular plasterboard screws to attach them to the battens or should i be using some kind of adhesive?
Etienne247 - will I need fit vertical and horizontal battens or just horizontal? Plus am I able to use regular plasterboard screws to attach them to the battens or should i be using some kind of adhesive?
Blunda - You should fit your battens vertically at 600mm centres to provide adequate support. You should use drywall screws to do this, however, you need to identify the source of your moisture ingress as this is a serious problem and does cause health risks in the long term.
The better solution would be to locate the ingress, rectify the problem at source, remove all plasterwork, treat the area of damp and then do as you like internally.
Sorry to repeat but you must identify why you have moisture ingress and why you have DPM behind your plasterboard. Previous owners maybe able to help you out?
This case is quite odd. Already having a DPM behind your plasterboard would suggest that there has always been a problem, or at least for some time. I'm not entirely sure there would be a standard solution.
The better solution would be to locate the ingress, rectify the problem at source, remove all plasterwork, treat the area of damp and then do as you like internally.
Sorry to repeat but you must identify why you have moisture ingress and why you have DPM behind your plasterboard. Previous owners maybe able to help you out?
This case is quite odd. Already having a DPM behind your plasterboard would suggest that there has always been a problem, or at least for some time. I'm not entirely sure there would be a standard solution.
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