Victorian terrace minor damp

ChickAt94

Hi,

looking for some advice on how to handle a bit of damp in our victorian terrace. We noticed it after finally removing wallpaper to paint after 5 years. Its a bit cold and you can see some water marks upto 50cm up walls all round the house. Its not mouldy or anything hence I don't think its bad. We have wall vents and trickle vents un double glazed windows.

I got builders to try and fit telescopic vents like all our neighbour's, only for them to find We have a concrete slab floor! Looks like put in the last 10 years maybe. There was evidence of slate damp roof course, but couldn't see how intact it was everywhere. The wall apparently felt moist inside. There is a meter ish high render on the front.

We were going to have a french gulley put in at the front as the tiny fron

20260410_095726.jpg

t is covered in paving which is probably too high.

But now i am nervous that there is no point doing a french gulley and it may impact foundations. Also considered taking down the bad render, but worried about brick damage. Also builder mentioned concerns about finding dodgy stuff when he digs for the gulley given the cracks in the render and window sill (ie should I worry about subsidence?)

His solution is to do a bit of chemical injection damp proofing and leave it at that.

Has anyone got any advice?

Thanks

WIAWSNB

What are the relative heights of the outside paving slabs and the indoor floor?

FreeBear

His solution is to do a bit of chemical injection damp proofing and leave it at that.

Injecting chemicals in to the walls will only reduce your bank balance and do nothing to fix the damp.

Digging a trench along the wall so that it is ~75mm below any DPC would be the right thing to do. It is usually recommended to go down 150mm, but your foundation will be relatively shallow and you'd risk exposing the footings. Aim for a trench 200mm wide and put a bit of gravel in the bottom.

The cement plinth is likely to be trapping moisture in the wall. But removing it will leave damaged bricks - This can be covered by using a pure lime render (no cement added, and no SBR), but you may struggle to find someone to do a proper job. If this builder is suggesting chemical injections, then he isn't the right person to do any work with lime and shouldn't be allowed near a Victorian property.

Novice_investor101

I’d suggest before paying out a lot of money for building works, get a decent dehumidifier & let it run on constant for couple of weeks in the most affected room. Preferably a couple of months.

I live in a Victorian terrace & had a damp lower wall issue that cleared up completely once I bought a dehumidifier. I didn’t realise persistent high humidity was the cause of it but it’s got rid of it & it’s not returned since.

I bought the dehumidifier because I was always cold downstairs even with the heating on & found it was really humid. I could smell the dampness coming out of the walls & was emptying the 2ltr tank every day for the first two weeks of running it.

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/81961695#Comment_81961695

This is not a bad suggestion and will help as a temporary fix, but at some point the source of the damp will need addressing.

flashg67

100% agree with both the french drain idea (I've just done the same but expect it'll be sometime before the wall dries out fully) and also removing the render and replace with lime render if damaged underneath.

I've also removed the skirtings on the affected wall, removed a few inches of plaster and replastered with lime which seems to have reduced mould & condensation a lot.

Likely you have a solid wall that needs to breath - chemical damp proofing and covering with cement will do nothing to help in the long run

ChickAt94

Hi again,

20260505_152509.jpg

Only saying that as others seem to have same on our street, though probably cement render.

Also had a quote to clean and repoint the front and its a bit much. Wondering if we can get away with just doing this splash band...

ChickAt94

Also have been running dehumidifier and feels warmer in the room quickly so hopefully doing a gd job on any damp!

Bigphil1474

Get another quote for the pointing. Looks like it needs doing up to about 3 courses above the window ledge. Worth getting done properly. We had similar at our old house. We had the kitchen drain there which added a slight complication, but we had that all dug up and replaced, fitted the french drain, and had the wall repointed up to about 2 meters.

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/81990825#Comment_81990825

Oh dear. That line of holes in the bricks (third row up from ground level) says the damp "experts" have already injected their magic potions. Probably slapped a layer of waterproof render/plaster on the walls internally. If you still have damp, that should be enough proof that these damp "cures" do not work.

Anyways, back to the wall - Patches could do with repointing. But respect the original construction and use a pure lime mortar. Three parts sand to one part NHL2 lime (no cement), or even NHL3.5. Use a yellow sand to match what is there. Unfortunately, it looks like the wall has been repointed with a cement mortar in the past. On the plus side, it appears to be falling out in places.

ChickAt94

Thanks for responses. Just realised 1st half of my post is missing, probably from uploading the image.

I meant to say, quote received from a brick person to clean, rake out and replace with lime pointing with nhl 3.5, lime render the band below window again. All the whole front of house to be done top to bottom. They suggested putting back the splash band on the brick in lime as other houses on street have it, so probably a reason for it. They can just repair and repoint if we want.

My question is

a) whether putting this splash band in will be a good idea or make damp worse. Should we just repair and repoint?

B) whether to just repair/repoint upto 1st floor and leave the top to save costs. My worry is it will not allow bricks to breath at top (though no evidence of damp i can see) and will look markedly different top half to bottom of house, making any buyer in 5 years time suspicious of a problem.

Views gratefully received!