1890's Victorian - West Facing Gable Wall, Cement Render and repoint, damp issues inside, lime plaster v Wood Fibre

[Stan5]

Hello,

I've just purchased a 1890's Victorian end of terrace property, it's a solid brick wall and around 30 years ago it was repointed on the west facing gable wall with concrete as well as a render 1.5m up the side of the wall.
Internally, where it had suffered damp issues along the bottom, it had more concrete plaster along the bottom 500mm of the internal rooms on the ground floor, clearly of the belief that it'll keep moisture out.

I've removed all the damp plaster upstairs and I've removed half of it downstairs.

The property now has serious damp issues, it has been vacant for 2 years and I'm sure this has compounded the problem, as well as very thick strong wallpaper that has helped trapped the moisture in walls.

My original plan was to strip back the plaster internally, and install wood fibre boards to improve the thermal performance of the property. However, I am concerned that with the gable wall already having it's breathability hampered by the concrete render and repoint, will the wood fibre boards pull enough water out of the wall that comes in from the exterior?

Would I be better off installing a lime based plaster internally which would help pull the moisture through the wall and out the other side by increased breathability but lower thermal performance?

Part of my thinking is that with the wall being west facing, it is likely to get a lot of heavy rainfall, so any improved breathability would really help mitigate the concrete repointing.

I know the correct thing to do is to repoint the entire house and strip off the concrete, but it's a very thin render and the small section I took off damaged the brickwork (Albeit, it had cracked pretty badly and was trapping moisture), so I am concerned I would also have significant repair job under the render once removed and did not budget for a full repoint in my house purchase, so it's something I would like to delay doing for 18/24 months if possible!

Another idea was if I only removed the bottom 9 inches of the render outside, would this let any water that got in behind the concrete fall down and release through the bottom? It's also most likely breaching the dpc layer, which I will lift up the floorboards internally and check today.

Uploaded pictures, can upload more if people need.

 

[ncr703]

Firstly, positives, what lovely fireplaces you have there. Congratulations on your purchase.

I'm just thinking through the timeline here and suspect the render (inside and out) was in response to a damp issue. I agree it's not helping, but it was probably an attempted mitigation to a primary issue somewhere. Alternatively it could have been misselling by the damp industry.

Having recently done significant work on my house for ground level issues, I'm immediately drawn to that concrete pad driveway situation adjacent to the wall with respect to internal floor levels, the dpc, and the under floor ventilation situation. In one of the pics the pad level looks almost as high as your door threshold.

 

[a twig]

Externally you could remove just the cement based render as carefully as you can and then hide the damaged bricks with an NHL2 based render.

If you have a DPC that render will be bridging it which won’t be helping things.

With the above said - damp plaster upstairs won’t have come from the ground so would imply some sort of failure higher up in rainwater management - roof or perhaps the chimney? Has it been capped and not vented? The mould etc looks worse there to me, so would be a good starting point and would help with air movement and ventilation.

That also ties into your point about the house being closed up for a couple of years - ventilation will definitely help - windows open as much as you can etc.

Not sure on your timescales but if you can remove all the damaged plaster and leave the bricks bare for as long as possible then they will dry out quicker.

Buy a few cheap humidity monitor and put one in each room so you can keep an eye on progress.

Once things seem to be drying out then crack on with the wood fibre and a lime based skim.

EDIT: agree with above point about ground levels but that wouldn’t be the cause of your upstairs issues

 

[a twig]

One other thought - not sure if you are planning on using the chimneys / fireplaces but if you are that always helps with drying a place out - heat and air movement