Damp on internal walls

[amanda1986]

I have just bought a 1930's house that was extended 12 years ago. when decorating in the dining room i discovered the wall between the dining room and kitchen had damp patches on the wall. I stripped the wall paper off and the plaster was damp underneath. When purchasing the house i knew they had had some damp proofing done last year so i assumed that it would not need doing again. The house has a positive air pressure unit on the top of the stairs which was switched off. I called back the company that had done the damp proofing and he told me that they had not that wall, but if i turned the unit back on it would probably resolve the problem. He came back today to test the wall and said that the wall was still damp so would need damp proofing. He has quoted £300 to treat & skim the wall.

I have a couple of questions;
1) Will i keep getting this problem or does damp proofing solve the problem?
2) Am I likely to get this problem on all walls that haven't been treated?
3) Does £300 seem a reasonable quote?

Any help is appreciated,
thanks, Amanda

 

[regsmyth]

I suggest you upload a photo of your damp patch for us to have a look at.


Also, some further details of the wall construction/extents of dampness would be useful, photos again ideal.

Timber floor or concrete floor?

Does the plaster stop above the floor (you might have to take off the skirting board).

You might get a better response if you post in the Building section.

 

[foxhole]

What relevance is the fact it has been extended, was this an external wall?
If so what was done at roof level? Single or two storey extension.?

 

[Burnerman]

Just to add to this....presumably you have a suspended timber floor? Is it possible to lift nearby floorboards to see if there is a DPC in the sleeper walls, check for air circulation from any air bricks and if the underfloor area is earth, is there adequate clearance between the floor joists and the underfloor?
John

 

[JohnD]

the most common cause of condensation, damp and mould in UK houses is people who drape wet washing around the house or over radiators.

A positive ventilation machine is often fitted by people who refuse to stop this habit.

Strip off the wallpaper, open the windows, see what happens.

p.s.
If you ask a company that sells damp-proofing what to do, they will usually say you need damp-proofing.

 

[maltaron]

I had a similar problem in a similar house (also in West Midlands) you will likely find that the dining room floor is timber and the kitchen floor solid. The damp was coming up the wall face as the solid floor bypassed the DPC in the wall. I solved it by cutting a slot adjacent to the kitchen wall down to DPC level and inserting vertical slates against the wall. You could also use wide plastic DPC. You will probably find that the DPC is Blue bricks.

 

[amanda1986]

Thanks all for your replies.

All the floors are now concrete which was done when it was extended. The wall is an internal wall and has always been internal. The walls are brick with plaster more or less all the way to the floor.

We have had the pressure unit on since we were told and the wall does feel dry but when the company put the tester on the wall it flashed up red.

I will take some photos tonight. but there isnt anything visable to see, i.e. no tide marks.

 

[JohnD]

the wall does feel dry but when the company put the tester on the wall it flashed up red.

almost as if the man with the tester was in the business of selling damp proofing...