Rising Damp

stuart45

Load bearing walls should have a foundation, but the others will be sitting on the slab. They should have a DPC under them, but the screed will bridge the DPC. If moisture is coming through the slab it could in theory be getting into the wall.
However a leak of some sort looks like the most likely cause.

ballamory

OK, so would a possible approach be to get someone to remove the plaster, and see what's going on behind one of those walls?   I'm not sure what the implications would be, though, for the tenants.  They have small children, and having a wall with a big hole in for an extended period isn't ideal.     If there is a leak to be seen,   fix the leak with a plumber and replaster.    If there isn't any obvious leak.. then what?    Would a builder of some description be the right person to do this sort of job?

stuart45

You need an experienced person to find the cause of the problem, but finding someone is often easier said than done. If the plaster is damaged it will have to come off anyway. You could well have 2 coats of sand/cement render behind it. 

ballamory

Forgive my ignorance, but where would any pipework, central heating or otherwise,  be relative to the sand/cement render?  Behind that?  So all of that would need to come off first, and then it might become more obvious what is going on?

Section62

ballamory said:

I've also read statements online that say only load bearing walls could ever suffer from rising damp, because only they reach down to the ground.  Partition walls do not.   How do I easily tell whether a wall is load bearing, or a partition?  If some of these walls are partition walls, then following this logic, they cannot be suffering from rising damp, surely?

Don't bother, because those online statements are a generalisation rather than a reliable statement of fact.  Some loadbearing walls don't touch the ground at all, some 'partition' walls have foundations.  It all depends on the age of the house, the building techniques used, and sometimes just what the builder found convenient.

To solve the damp problem you need to find the source of the damp.  The most likely, and probably the cheapest to test for, is a leak from the heating or hot/cold water supply pipework.  A decent plumber will be able to test the systems and see whether there is a possibility of leakage.  Don't rely on the boiler not losing pressure as that isn't an absolute indicator of no leak on the CH system.

jonnydeppiwish!

What’s above the walls? Bathroom? Toilet? Roof? Chimney breast or remain of above?

ballamory

Thanks Section 62.  So the first thing I do is get a plumber to test for leakages in either the central heating or water supply.  Before taking out bits of any walls, or anything like that.  How do they typically establish that?  Drops in pressure, or things like that?

jonnydeppiwish!

the wall backs onto a bathroom? Where are the drains located? Can you confirms it’s the same wall but either side of it? 

ballamory

Hello jommideppywish

It's a bungalow, so there's roof above the walls.  Or rather a fairly large loft space.

jonnydeppiwish!

ballamory said:

Hello jommideppywish

It's a bungalow, so there's roof above the walls.  Or rather a fairly large loft space.

Just for your own piece of mind, check that there’s not leak in the roof, either from the roof or a header tank, if you still have one.