Mould in corners of several rooms

[DJB]

Bought damp meter today (and yes they're not a reliable measure of damp but better than nothing) to assess the most damp regions of the wall at the back of this cupboard (the one next to fireplace). The readings are high all the way up the brick-work and not just at floor level. They seem to be worst on wall adjacent to chimney.

On knocking out brick for replacing with air-brick vent, I noticed that brick and mortar seem damp (this is about 40 cm above floor level inside). Makes me think that the damp may have come from above (when chimney lead flashing and/or tiling were leaking. Too many possibilities!

D.

 

[Nemesis]

No on fact they are pretty useless in many circumstances, and certainly in inexperienced hands.

And yes - as I said above - if it was leaking from the roof/flashing it may well still be damp and could take quite some time to dry out.

 

[biffvernon]

Damp meter? You obviously haven't got damp like us. Woke up to find a river pouring down the wall (indoors). Buckets, mops, towels....

Altogether now, (to the tune of an old pop song)

The hole in my roof
It is letting in water
Letting in water
Letting in water

http://en.wikipedia.org/wiki/Hole_In_My_Shoe

 

[Nemesis]

Oh dear!

We had water pouring in last week but that was via a hole in the wall (at the base).

Hope the damage isn't too bad.

 

[DJB]

Trying to decide on best strategy for eliminating problem and allowing decoration soon - I cannot wait for months for bricks to dry out. Read survey report from company. They have included fitting of Delta PT membrane behind plaster coat. I've read up on this and it seems sensible. It should allow movement of air between membrane and brick. Tempted to fit this as well as above work. Will it do any harm?

D.

 

[Nemesis]

Not sure now you are listening to anything said.

Why the rush? Why not allow it all to dry and work with the building instead of trying the quick fix?

 

[charlie-ia]

the damp faq is right at the top of the forum index page now as a "sticky"

 

[Gervase]

I've read up on this and it seems sensible... Will it do any harm?
D.

Not 'ere you aint - and maybe.
It will prevent the wall from breathing and could trap moisture in the fabric. It's not what a conservation officer, or SPAB. or indeed anyone involved professionally in conservation would recommend as a first course of action

 

[Matt Green]

There are far, far too many varibles to make a judgement call on this.

The situation needs a invasive survey to determine where the water is coming from and what can be done about it.



Matt

 

[DJB]

Despite all advice, I'm still not certain where damp is coming from. My approach to dealing with it is to assume several possible causes.

1. I have taken steps to improve ventilation (windows partly open all the time, underground vents cleared, new air brick vents installed above ground).

2. Injectable DPC carried out (DryTech) in problem areas. Care was taken to inject at different level from original slate DPC so as not to damage it.

3. Roof/lead flashing leaks sorted.

4. Underfloor rubble cleared away from internal DPC.

5. AND finally because I think that it'll take about 6 months for the brickwork to dry out, a damp-proof membrane will allow me to decorate before the walls have fully dried out. The membrane is sophisticated and maintains a space between membrane and brick to allow air circulation and therefore should allow the brick to dry out after plastering.

Why the hurry?

I've run out of money to spend on renovation and need to re-mortgage to allow any further work to proceed. I suspect that if the property is valued in its current state (bare walls, plaster work unfinshed), I will not release enough equity to settle current borrowing let alone provide for further work.

D.

 

[NT]

One can lime plaster a damp wall.

You really need to stop and take time to understand what is going on, youre just not going to solve it otherwise. I would not introduce membranes, dual dpcs, or any other such products that are just missing the point.

FWIW it seems clear that it is condensation. In corners and behind cupboards on 4" walls are exactly where it will form most.

The as yet unknown is what is causing the high interior RH. The damp faq should point to some simple initial options.


NT

 

[DJB]

A new finding at the weekend. You might remember one of the main problem areas is adjacent to built in cupboard (which is next to working fireplace). The corners of two adjoining rooms had mould on the walls at floor level. Underneath the study (room without fireplace/cupboard) a large joist (8x4") runs from one side of the room to the other. At the end nearest the outside wall (same wall that is behind problem cupboard), the joist goes through a brick-sized gap in the inner leaf of cavity wall. This joist is visibly wet and indeed there were drips of water at the end of it. There was bits of rubble and degraded loft insulation around it perhaps bridging cavity. I've tried to clear these. The slate that the joist sits on is clearly cracked but the slate DPC below this looks ok.

What is the likely cause of this damp? Obviously my concern is that wet rot will ensue.

The same joist in the next door room (beneath fireplace) is already rotten at the same end due to contact with wet rubble (I think).

D.

 

[Raylea]

Hi,

How about some pictures so we can see what your seeing. If you can.

Raylea

 

[DJB]

Will try to get pics nect time I'm under floor although given the fact that there's only one access point (hall) and the solum to joist clearance varies from 12 to 18" this might be difficult!

D.