Trapped Water in Walls

[dooogle]

Can someone please help me? I have what looks like damp at the front and back of my house. The house has been damp proofed (6 years ago), guttering replaced and stink pipe replaced and still have this problem. At the front of the house, the damp is from the ground up and majority stops half way up the wall, however, there are damp spots rising sporadically to the top. My initial thoughts are that the damp proof has failed or water is inside the walls and cannot get out! At the back of the house is where I really do have a mystery. Damp is from the top of the house downover and stops where the damp proof course was carried out. We have checked guttering, seals etc and cannot find the cause. We do have a cellar and not sure if this has a contribution to the damp/water or the trapped water has no where to escape or is not evaporating - as you can tell I am no builder!!. Please, I would appreciate any guidance at all, I love my house and am distressed that I cannot fix it. a huge thanks for any help you can give.
Best wishes
Donna

 

[Gervase]

How was the house damp-proofed? if it was by chemical injection, then the proofing will almost certainly have failed - it doesn't work, and the companies that push the stuff should be hammered by trading standards!

It does sound as though there is moisture trapped in the walls. To get nearer the cause, though, some more info is needed.

Are the walls brick or stone, and how thick are they?
Do you have any rendering on the outside, and what's the plaster like on the inside?
Are your ground floors solid or timber with an air-space underneath?
What condition is the pointing in the brick/stonework outside?
How do the dampest walls compare to the prevailing wind?
Are the damp walls gable ends or do they have eaves and guttering?
What's the ground level like outside - are there any places where it is above the inside floor level (the cellar not included, of course!)?

 

[dooogle]

Hi thanks for your reply. in answer to your questions, the damp course was chemical injection, but the installer has died and the company has ceased trading.
The walls are solid brickwork, no cavity and about 18"thick, no rendering. the internal plaster is damp with salts forming on it.
The floors are timber and have a 4ft gap between them and the cellar floor. the walls have all been pointed, but have since been painted with masonry paint.
The damp seems to start in the upstairs bedroom (little) and gradually get worse as it gets to the groung floor. but on the back of the house the damp seems to stop above the dpc, where the plaster was removed and replaced, this is not the case at the front as it goes right to the floor and under the bay window, the walls are not gable and do not have eaves, the guttering was rapleced about 8 months ago. could water ingress then still remain in the wall till now.
the ground level outside at the back is 8ft below the top of the dpc and the damp. the front is as internal floor level and has been concreted outside.

i look forward to your reply.

thanks

 

[NT]

dooogle

chemically injected dpcs dont really achieve much in most cases, but the plaster applied afterwards hides the damp material for a while.

Masonry-painted walls is a problem, this prevents the normal evaporation of damp that is key to old house walls staying dry. There is a vortex thingy that can strip it off, but I've not used it myself.

If you've got damp symptoms from top to bottom then most likely the interior RH is high, so looking at interior sources of water should also be considered. Eg open showers, and lack of normal ventilation caused by draughtproofing and blocking chimneys.

Ground needs to be below floor level all round, if its not then a bit of spadework is called for.

Underground cellars are a source of a fair bit of damp, which will need addressing.

However since youve got quite a heavy case of damp, it would be good to go over this in a fair bit more detail. First thing is to familiarise yourself with all the usual causes of damp, check them out and repair anything that needs doing. Include a good look at the roof too.

Meanwhile a humidistatic dehumidifier would really help.


NT

 

[dooogle]

http://cgi.ebay.co.uk/WATER-PROOF-DAMP-WET-PENETRATING-DAMP-EXTERNAL-WALLS_W0QQitemZ7627073335QQcategoryZ26197QQrdZ1QQcmdZViewItem

would this be any good? and what is interior Rh ,

thanks for the reply

 

[Moo]

I think the general consensus here would be DON'T TOUCH IT WITH A BARGEPOLE.

It uses the same logic as getting out of the shower and wrapping yourself in a plastic mac. Sure, bricks get wet. But left to themselves they dry out again.

 

[NT]

http://cgi.ebay.co.uk/WATER-PROOF-DAMP-WET-PENETRATING-DAMP-EXTERNAL-WALLS_W0QQitemZ7627073335QQcategoryZ26197QQrdZ1QQcmdZViewItem

would this be any good? and what is interior Rh ,

thanks for the reply

1. if you tell us what it is maybe youll get more answers
2. rh = relative humidity

You dont need a product, you need to identify the causes of damp.


NT

 

[Penners]

I think the general consensus here would be DON'T TOUCH IT WITH A BARGEPOLE.

It uses the same logic as getting out of the shower and wrapping yourself in a plastic mac. Sure, bricks get wet. But left to themselves they dry out again.

Great analogy, Moo!

Just about the worst thing you could do, doooooooogle, is to "waterproof" a damp wall.

 

[Moo]

I've found it quite a useful argument with builders, too. It's really rather beautiful, seeing their minds creak open and let the glow of enlightenment flood in.