Irregular pattern of dampness in Victorian conversion

[utb99]

Hi, another damp question I’m afraid. I’ve done some research here but still trying to decide the best avenue to go down so wondering if anyone here might be able to advise.

I have recently moved into a lower and raised ground floor flat, which forms part of a mid terrace 5 storey Victorian house (1880s). When I purchased it I was aware there was a damp problem which the vendor had got an estimate for of £8k and I ended up negotiating to take it off him and do the work myself once I’d had the survey.

Basically the extent of the damp is on the lower ground floor on a number of the walls. The paint has peeled off in certain parts of some of the walls, sometimes along the bottom (where there’s a bit of mould in a couple of places), other times much higher up towards the top and middle….so at fairly irregular places.

I’ve had two firms round so far. The first suggested the lower bits of damp were due to rising damp (hence replaster + damp proof course) and also to penetrating damp for some of the higher bits (he recommended replastering with a specialist waterproof plaster here – tanking). The second said that it was all due to hygroscopic salts in the bricks (from rising damp and water pushing up from the ground in some cases where the lower plaster was better and then coming out as dampness higher up when the plaster wasn’t as good) and suggested damp proof course + replastering of affected areas + replastering of many of the unaffected walls (at least no problem to the naked eye).

I’m quite sceptical of both as they both just went along with a damp proof meter and I’m concerned that they may be replastering stuff they don’t need to. Not sure if anyone here has had a similar pattern of dampness before?

So would it be my best bet to get an independent specialist report who wouldn’t be doing the work hence no reason for them to recommend unnecessary works? The surveyor recommended Specialist Xpress (they charge £150) – anyone heard of these or got anyone else to recommend?

And once I’ve got this report has anyone got any good recommendations for damp proofing firms?

Thanks (and apologies for the length of the post!)

 

[JMartin]

I'm no expert but I would be checking the exterior of the house for faults with the pointing and render (if applicable). We had extensive damp on our gable end and this was wholly caused by cracked render and the ground being too high outside the house. The damp surveyors we had in all wanted to put in a chemical DPC which would have made the problem worse rather than better.

There's a sticky topic for damp at the top of the forum. Have you read that? It's got some good pointers for discovering the source of damp.

 

[Matt Green]

The paint has peeled off in certain parts of some of the walls, sometimes along the bottom (where there’s a bit of mould in a couple of places), other times much higher up towards the top and middle….so at fairly irregular places.

I’ve had two firms round so far. The first suggested the lower bits of damp were due to rising damp....

Mould.

Try growing mould on a surface treated with salt, try growing anything on a surface treated with salt. Wont work very well.

So there's no salt. So it's not likely to be ground water penetration. So its fresh water, occurring in patches on a lower ground floor wall.

Diagnosis points to condensation so far, but it's a lower ground floor, and we don't know what the walls are finished with. Emulsion paint?

Is there a well area next to the low-level damaged areas, and does rainwater run into the base of the wall?

At high level: is there a set of steps leading to the ground floor door, and it there damage near them- water run off for example?

Need some pictures at this point.



Matt Green
-the Gregory House of damp threads.

 

[Nemesis]

Well, the firm mentioned above I had never heard of, so I did a google.

It came up with the startling revelation that for 'rising damp, condensation' what is required is a damp report. There is no indication, however, that those sent by this firm (for a fee...) will be any better at diagnosis, and coming up with an appropriate solution, than yer average man with a van and damp meter.

Listen to Matt, he does know what he's talking about (at least when it comes to damp and timber...)