Damp in 1850s house

[Bloomsburyreader]

Extremely grateful for answers I have been given when asking about what type of flooring we have in our new house but I thought it sensible to open a separate thread asking about the damp issues.

When we first looked at the house we had the place surveyed and were told there was some rising damp, not surprising, we were told, there is no damp proof course in an old house, but also that as the property had been empty and unheated for the whole winter there had been further damage -ie not all the damp was due to rising damp.

The condition of our mortgage was that we had a retention and we would have to prove the damp was sorted before getting the full mortgage. This is because the lenders surveyor spotted the damp on the valuation visit.

They asked us to get a quote to sort the damp and so the retention is the cost of the quote given. The quote for remedial works was for cementious tanking to be applied and then a specialist membrane placed under new plasterboard.

I get that this is supposed to sort a problem but sticking plaster over the top doesn't stop the damp problem and we feel like the walls will just be dry on the outside but wet on the inside and slowly crumbling away. Walls in the original part of the house, where the main problem is, are 40-50cm thick

Today I peeled off the wallpaper (thick vinyl stuff that delightfully kept the water inside the walls) and I discovered that there has already been tanking half way up the walls. I think this has been done more than once! So we know it isn't a long term solution.

We are thinking of pulling out of the damp proofing appointment (even though we had to wait 6 weeks does it) as it does not seem the right solution. We want to find out what causes the damp in the first place (we have dug down one of the flowerbeds as that was far too high but the wall by that was not the worst).

Am I right to be pulling out of the appointment or should we just go ahead with the tanking and membranes? It feels that way would be saving up problems for years down the line although we are likely to move area in 5 years so may just sell before this becomes an issue! Anyone know if our mortgage becomes invalidated if we don't go ahead?

Pic is of reception room where you can see that tanking has been done already

It might be worth getting a decent dehumidifier in the meantime to reduce it where possible which might help the works a bit easier.
We still use one even with all the works done for when we have washing in the house so that the house stays at a good balance.

It isn't render we need to remove, actually, it's the cement mortar that some moron repointed the house with at some time in the past, when it had previously been lime. (We do have render as well, but that's above brick, the render is fine as it's doesn't start until about a yard up the wall).
Irritatingly, the aforesaid moron also used, clumsily, something like a disc cutter to rake out the lime, which has chipped all along the edges of almost every brick, even though they are very hard Accrington brick- they even cut into the bricks above and below when they were clearing out the 'perps' (the vertical mortar). It's going to be very difficult to do the lime pointing and make it look good as a result.

[quote IamwhoIsayIam]@Bloomsburyreader - the passion for your house and this project rings through! I have the feeling that with the care and research you are putting into this you will have a lovely home at the end. I hope you keep sharing your story.

We have a small amount of damp in our 1890's stone cottage just on one west facing wall. We are going to get the pointing re-done in lime and repaint inside as the paint looks like it has plasticiser in it as the damp 'bubbles' away from the wall. It won't be until next spring now - so it could be a cold damp winter ahead![/quote]
We were advised to use claypaint, as it breathes, or limewash. In our case, claypaint was okay because we have brick cavity walls, not sure if that would work in your case. It does seem to work well here.

Brandwise we were recommended to Earthborn's claypaint. Claypaint isn't as hardwearing as the modern synthetics, and the colour choice is limited, but is has a lovely velvety matt finish and is a dream to put on. It has lowish coverage in terms of paint per sq m, but is very opaque so needs fewer coats. I would use testpots when choosing colours, though, even though for modern paints I don't usually bother, as it can take light oddly.

Another cause of damp could be a leaking water supply pipe under the floor, especially if the house hasn't been replumbed since it was built.

I lifted the floor boards in the cupboard under the stairs in our 30s house and shone a torch into the void below only to be met with my reflection. The house still had lead pipe work and the water was pissing out creating quite a lake under the house. We had the whole place re plumbed from the pavement to the internal stop tap with modern poly pipe and the place started to dry out almost immediately.

www.heritage-house.org/damp-and-condensation/managing-damp-in-old-buildings.html