Damp spot on internal wall?

Question

Hi, we have just moved in to a new house, which has had a recent DPC. However in the living room, on the inside of an external wall we have noticed a damp patch...about 1.2m above floor level. There are no pipes in the wall. It is wet to touch and paint is left on your fingers.

Is it possible that heavy rain is penetrating the wall? what do i need to do to fix it?

Any advice is much appreciated!

Thanks!

-yes, it has alrady had a damp proof course (just last year and 10 years before that).

-the damp patch is quite near the window

-the DPC has a ten year guarantee, just wanted to check if it was relevant before contacting them.

-i'm not convinced that its a window, as theyre newly installed windows... also the patch is about 2 feet from the window. is it still possible?

Answer 1

Contact the company that undertook the dampcourse. It could be that the prep work for the DC was not thorough enough or that there could have been a problem that they spotted, but could/did not solve in the fabric of the building.

The window instalation could have moved the brickwork and that sometimes causes problems, rather than the windows themselves not being fully sealed and installed.

Good luck

Answer 2

You need to use a process of elimination. For example, if it remains wet, moisture must be getting in or else it would just evaporate. The main sources of dampness in walls are rising, penetrating, and condensation.

When new dpc's are installed, the walls are replastered to about 900mm above floor level with a waterproof plaster. This can have the effect of pushing serious rising damp further up the wall.

If penetration is the problem you need to check what is going on the other side of the wall. What is the pointing like? Is it damp there too?

Condensation is the result of warm moist air coming into contact with relatively cold surfaces and could be localised if you have a spot of very absorbent plaster. Heeating levels, ventilation, and insulation all need to be right to keep condensation levels low. This problem is usually combined with black mould growth.

And how can you be sure there is no pipe in the wall? Have you opened it up?

Answer 3

Hi, is it in the corner of the wall? If so it could be missing a vertical DPC (damp proof course) this stops rain penetrating the builing at wall joints etc. the same would also apply if it is near a window or door (or infact any connection between inside and outside where there is no cavity (gap) between)
To fix, put in a vertical dpc- expensive. Or you can buy damp spray or get damp proofing injected by a company. All quite costly but should sort the problem.

Answer 4

I am guessing your water is finding its' way in through the window. In my experience, this represents about 90% of the cases where a window is at or near the site. Furthermore, it sounds as though considerable effort has been made to seal the exterior walls.

There is a subtle condition to look for in the window that is sometimes overlooked. Often, the bottom jambs are not sealed properly in the factory, and if water sits in the sill, it will leach down in the corners of the window to the wall and floor below. Screens are notorious for blocking the weepholes that allow water to run out of the jambs. By damming the water, the screens virtually assures an eventual leak.

To seal the very tricky wnidow jambs after the fact, I use the pointy q-tips used for make-up application and polyurethane caulk. (O.S.I. Pro-Series , white, $4.50 at Home Depot). With a Shop-Vac and a small utensil, suck out every particle of debris form the jamb corners. Clean the area well with mineral spirits and the q-tips. Wet a new q-tip with your mouth so the caulk sticks to the window and not your applicator. Squeeze a small amount of polyurethane caulk into the jamb area, and carefully dab in a tight seal with your applicator, keeping it nice and low so the window doesn't sit in it when lowered.

Good luck and God bless you.

Answer 5

In no way am I well versed in buildings or contracting, but if the paint comes off on your fingers, either that spot was freshly patched right before you moved in or there is something corrosive within your wall. Maybe you can take some of it to a local builder's warehouse on a moist papertowel and ask them. The workers there answer mysterious housing questions all day everyday. Hope this gets fixed for you.

Answer 6

you seem to have 'rising damp' and you need to have damp course done.

if you ignore it the damp will penetrate further up the walls and damage the structure of your house.

did you not have a full survey done before you put an offer for the house??

search google for 'damp course'

you can do it yourself if you know what you're doing.

if not, theni advise you to call RENTOKIL or similar good company maintenance - they will come and do a very professional survey (good companies dont do free surveys) and tell you what needs to be done.


good luck !

Answer 7

If you have just moved in it should be covered by guarrantees which your solicitor checks are in place before you exchange contracts shouldn't it? The damp proof company should come and fix it.

Answer 8

I had the same problem - it's the plaster work in that particular bit of wall. (Probably older material). It will need knocking out and filling with modern plaster! Sorry!