surveyor for damp wall/recommendations for thermal bridging in Birmingham please

[youngerself]

I have had no luck with local people so trying here.

I have only 1 wall in my whole house causing a problem. In upstairs bedroom.

It seems that the dab and dot in one area on one wall is causing thermal bridging causing damp patches at the back of fitted wardrobes leading to mildew on contents.

I have spent lots on the roof and my roofer is adamant that it is not letting water in.

I am considering thermal wallpaper or having the wardrobe removed and the wall redone with celotex or insulated boards.

I would like a surveyor to assess the roof and walls - possibly with a drone? - and ?thermal camera. I don't want to fork out more money without being sure of the problem or remedy.

Many surveyors sites talk of home buyers surveys and others seem to be property management companies.

How do I choose one for this specific issue? Is the technology needed normal stuff for them?

Birmingham area.

Any thoughts welcomed.

What would you expect a thermal camera to show when you point it at your inner wall ?

I have one. What I can see is cold blobs where the adhesive is. Interesting but what then ?

For me the issue is not so much that dot and dad adhesive forms cold bridges to the wall (it does), but your wall is that cold in the first place. Why is that ? Some sort of problem with the cavity ?

I would expect if damp is coming from the roof it would travel down the wall, from top to bottom. So the top of the wall should be damper than the bottom. Any evidence of this ?

Are you sure that the problem is not just excess living humidity finding its way to the coldest point in the house and condensing out ? What happens when you try to dry the room out and what is the overall house humidity ?

What is the situation with the wall below ?

It's a west facing wall. No cavity as built around 1860.

No the damp patches are not more pronounced at the top. Sort of blotchy spread mid wall. About 8 patches.

It's been a problem since moving in 11 years ago but I think it's worse in recent years. It maybe since DC have left home and we are away more.

It is not a problem anywhere else in the house.

The humidity was high 70's. Running a dehumidifier get bedroom down to 55-60.

Surely if it is only 1 part of one wall, there's a solution

Are the bricks covered in a coating? That's what is causing my damp. I got an independent damp surveyor who confirmed this.

Yes, if it’s a solid wall, what is on the external face? Render? Just brickwork?

Yes - the whole house is rendered but this isn't a problem elsewhere in the house.

I'm wary of damp surveyors because of so many reports on them using inappropriate techniques on older buildings so I thought a surveyor would be better. Damp surveyors seem linked to damp proofing companies and again, how to choose a good one?

What about pipes/drips down that part of the external wall ? Any reason to suspect the render has somehow failed in that part of the wall ?

If the problem is caused by damp from outside then I am not sure patching the inside is a solution. Whoever patches it up will probably put a moisture barrier in between the internal insulation and the wall. But the wall will continue to get damp and it will probably spread throughout the entire wall. If it is caused by damp I am not sure this is a solution, or at least a permanent one.

If it is caused by that wall simply being cold, and the wall itself is not damp but moisture is condensing on the cold wall from the inside, maybe it will solve the issue.

The bargeboards/soffits are dry and the gutters are not leaking and the down pipe is clear.
There is no water marking on the wall or round gutters and the rendering doesn't show any cracks
This is what the roofer has said hence thinking it's condensation on thermal bridges

I don't live in Birmingham but the damp surveyor I used was one who does surveying for house sales. He was not linked to any damp proofing company and didn't try and sell me anything as he had nothing to sell.

If the render is impermeable but has one or two cracks, on a weat wall wind plus rain could be driving water in to the wall, but as that water cannot dry out back to outside it is soaking through the bricks into the indoors instead.

If it is a flakk wall you may be able to externally insulate with a weatherproof system (ideally during a summer when it should hahaha be a bit drier, then thoroughly warm and ventilate the affected room.

Not local, so no local recommendations but we used Permarock (admittedly ages ago) to insulate the whole house and were very pleasd wih the service

WEST wall!

Dot and dab plasterboard, and any other modern impermeable materials, are completely inappropriate for a solid walled house. Everything needs to be breathable/permeable.

And FGS do no use celotex or similar, massive fire risk and ants love it.

SPAB is the best resource.

Thank you @Scampuss

I have looked at the SPAB website and can't see any links to surveying services. This is the sort of stuff that I need a surveyor for - celotex was recommended elsewhere (MSE)

You almost certainly don't need a surveyor! Just follow SPAB advice on appropriate materials. Their Old House and Eco Old House books are very useful.

The FB group 'Your Old House UK - repair and conservation' is incredibly helpful.

Thank you
I'll look at those