Damp proofing an internal partner wall where ground levels differ
Anonymous user 15/03/2024 - 2.48 PM
Hi, please could someone advice. I live in a 1900s terrace house where my neighbour's ground level is about a meter higher than mine. The partner wall with the chimney breasts is extremely damp. It looks like an attempt to fix this has been attempted in the past as there is a sand and cement render on the wall - this is apparent after I hacked some of the plaster away.
I've been doing some research and it seems houses of this age (pre 1930s) were built using lime materials and designed to "breath" with ventilation.
However my house looks like the walls have been rendered to hide the damp and now they are saturated on the side where the neighbour's house is higher than mine.
I'm not sure how best to manage / fix the issue. I've had two damp inspectors inspect the house but they recommended stripping back the render and re-injecting another damp proof course and re-plaster using a waterproof render/plaster mix - again!
After looking into these methods online it appears this is really bad for the house as it will lock in water vapour into the walls.
I'm planning on resolving the situation myself (due to budget constraints) and want to know how best to resolve. I'm thinking of removing the plaster and render from the walls and re applying a plaster board using dot and dab technique, as this is the quicker and least disruptive solution, and will improve ventilation, however I'm worried the damp, salts of water vapor will penetrate the boards, especially where the adhesive will be used to attach the boards.
- should I be using plaster board as a solution or line render mix?
- as the damp issue cannot be resolved (due to neighbour's higher ground level) would lime sand render is the best or worst solution
- are there any adhesives out there that damp and salt cannot penetrate - so as to prevent contaminating plaster boards
should I be applying a membrane on the wall before applying the plasterboard
should I be using a breathable plaster board, or will standards boards be OK?
Any advice would be greatly appreciated.
Are you a tradesperson and able to answer this question?
Hi Steve,
Plasterboard will saturate and become damp. You are right, these houses were designed to allow moisture to pass through the walls and, when it is prevented, things become damp. Cement is a waterproofer and waterproofing an old house is the completely wrong thing to do.
Lime plaster is needed but you have to remove the cement and gypsum plaster off the wall, especially at low level near ro the hearth.
Improve airflow below the floor, make sure external ground levels are below the damp proof course, check drainage ro make sure it is clear and not leaking. Lots of defects associated with old building that often get ignored, these are just some of them.
Happy to help further.
Ignore damp proofers. They need to sell their damp proofing to make money.
Answered24 May 2019
3
Anonymous user
Sounds like you have a soil retaining wall and a damproofing course would be useless in the case because it is not rising damp its penetrating a would strongly advise using a hessien membrane being installed prior to the dot and dab to prevent a bridging issue
Answered23 May 2019
2
Anonymous user
Going back to a proper lime plaster is the official way of doing it but you must know how to mix and apply.
If money's tight batten the walls vertically with roof tile battens and screw plasterboard to battens. Leave a 25 mm gap at the bottom and cover with skirting. At the top cut back the ceiling plaster in line with the new plasterboard making sure you have a small gap behind the plasterboard that has exposed the underneath of the upstairs floor or roof space if up stairs.
This will allow a small amount of air to circulate behind the plasterboard. Plaster and decorate as usual.
This is not how I would do it but I have done this for clients who just don't have the money to lime plaster. At least you improve the quality of your environment and the building at a reasonable cost.
Don't use plasterboard adhesive it will come through.
There is no such thing as rising damp.
Answered29 May 2019
2
Anonymous user
Remove the render , paint the wall with syitherproof my spelling is not great we call call black jack it’s sold in Travis & Perkins . Then dryline , don’t attach the timbers to the wall use 2x2 leave a slight gap between wall and timber , once you have built the wall clip polythene on the front ( vapour barrier ) then the plaster board , when fixing the plaster just peg up off of the floor only slightly so it’s not touching , plaster job done . Dot & dab the wall would not be the way to go common sense suggest the board would get damp very quickly, plus the dabs would grin through like damp patches !!
Lime plaster is a good way to go to help minor moisture issues i.e. condensation, but you have to take into account hygroscopic salts , lime plaster will not stop hydroscopic salts and using an anti sulphate is not a full-time solution . so depending on if it's a cavity or non cavity structure depending on the volume of moisture and the ground levels the easiest and the cheapest way would be to apply the Delta membrane and replaster. this way you've guarantee that you have fixed the problem , as it can become a costly process.
Answered5 June 2019
0
Anonymous user
The easiest solution for you would be to install a cavity membrane to the wall floor to ceiling then you can dot and dab plasterboard to it you will never have any issues if done correctly
