damp part way up walls

[julie_dee]

I'm renovating a room in my house and am confused about the damp on the walls.

One interior wall, which separates the back room from the front, is damp. Confusing point; I've been removing the old plaster and it comes off really easily at about 3ft height but is really difficult and appears to be well attached from the base up to about 1ft height, but the wall is damp all the way up to about 4ft height.

At the base of the wall I've found what I think must be the old damp proof course. This problem is the same all over the downstairs of the house.

I'm assuming that it's rising damp and am going to treat it with a new damp proof course (dryzone) but any other ideas? The floor of the house is at ground level and is built on a concrete base, so I can see no signs of underfloor ventilation.



Cheers.
Julie.

 

[anobium]

The plaster 1 metre up from the floor is probably not plaster but a sand and cement render which some companies put on the walls to hide a damp problem. They probably also installed a chemical dpc at the same time.
The problem you now have is more than likely condensation because the render is so dense it will not absorp moisture.
Check if a dpc was installed, there should be holes either in the bricks or the joints at approx 10mm centres. If so pointless installing another dpc or removing render, suggest that you take steps to eliminate condensation problem, usually by ventilation ,insulation or extra heat.
If the house has been empty for some time without heating the problem may well be rectified when it is occupied.

 

[julie_dee]

cheers for the advice. It makes a lot of sense. There is no damp proof course so I'm installing one and am taking steps to ventilate the walls and house in general better.

This was my first post on this site and first impressions re advice given are good, so thank you.

Julie.

 

[Nige F]

Brick / block walls used to be rendered with sand/cement then set with plaster..so yours may/not be a waterproof render.......plaster is c.2mm thick.the render under is c.12mm......then you see the brick/blockwork.