Could condensation on pipe cause this ?

[thetcutkid]

OK ,that rules out the possibility of travelling damp. I notice there is a big difference in the two pics with regard to the density of the mould. I assume it is laying on the surface and you have easily removed some if it , by chance or on purpose. Anyway ,if you can remove it and the plywood below is sound its obviously not inherent or penetrating from below. Is this so ?

Hi Terry,

Yes, in checking how bad it was, a screwdriver and stanley knife were used in probing the wood and flaking pieces off, I also used a brush to collect up the pieces of plasterboard I cut out so that area has been rubbed a lot.

I really wanted to get that whole section up to check the underside of the boarding but frustratingly, where there used to be an inspection hatch cut into the old floor, this was removed when the new boarding went down and its now a large, complete sheet.

 

[thetcutkid]

We had a job a few years back in New Bond Street, clothing store being fitted out and reports of a leak in the basement.
We considered codensation but there was so much water and damage to building fabric, that it didn't seem plausible and so we carried out tests and investigated further over a few days.

It was indeed condensation... The 2" lead main wound itself in and out of the brickwork, from the old coal chute (under the road) to the back of the basement and up to the 4 floors above. Everywhere it emerged from the wall, it was soaked... Condensation beads on a pipe and immediately starts to reappear once wiped dry, if the dew point persists, this results in the beads coalescing and gravity takes over to form a trickle, gathering partners on the way down to form a drip at the lowest point... in this case it was literally pouring off lead at various points.

If you are able to wipe the stain away then I'd say it's indicative of water running down from above and forming a mould, rather than damp penetration from below... As @terryplumb mentioned above.

The main running, uninsulated, in a void between exterior brick/block work and internal thermal panelling is a prime suspect for condensation.

I'd expose as much of it as possible and insulate it now, unless you can wait until winter and monitor it at the point where the floor has become stained.

Hi Dilalio,

Thanks for your detailed reply.

The dampness is definitely more than just on the surface, the top few mm is quite soft, you can push a knife or screwdriver into the wood, not all the way through tho. I would very much like to have got that whole section of boarding out to check the underside but unfortunately the inspection hatch that used to be there was removed when the kitchen was boarded out.

In your opinion, how far up should the pipe be insulated in the wall (obviously I'm mindful of not having to destroy too much of the false wall). Is the foam insulation with the hole and split side running through it suitable for this scenario?

 

[dilalio]

In your opinion, how far up should the pipe be insulated in the wall (obviously I'm mindful of not having to destroy too much of the false wall). Is the foam insulation with the hole and split side running through it suitable for this scenario?

You can only do what you can! Might be worth leaving the location accessible for checking in the colder weather when the temperature of incoming water drops. Foam lagging should definitely help but you won't know if it's all covered up again come winter!

 

[thetcutkid]

I can see the sense in that, I could probably put the skirting back temporarily and try and make the area look tidier.

I have to say, just me having a rant you understand, how these sort of jobs just snowball in the total ballache department - my mum reminded me that the guys who put the boarding down cut a section in front of that area as a kind of inspection hatch about 2 foot square.

Brilliant I thought...however, the floorer who laid the Karndean floor put 5mm ply over the entire floor to give him a smooth base I guess. No worries I thought, I can see the screw heads, with the screws removed nothing really happened. It turns out that right over the inspection hatch the 5mm ply was glued down with enough adhesive to stop a rhino.

I've just spent a very 'enjoyable' day on my knees with a mallet and chisel trying to get this ******** ply off the flooring beneath, only to find that the inspection hatch is not perfectly square on one side but cut in a set of attractive angles which extend further under this ******** ply.

The other thing that made me larf hysterically was that on the section I did clear, the screws that hold the flooring to the joists had their heads rounded off when it was put down, so even if I could clear enough ply to expose each edge of the hatch, I'd never get it up because I can't undo the poxy screws.

I'm not happy....

 

[dilalio]

I can see the sense in that, I could probably put the skirting back temporarily and try and make the area look tidier.

I have to say, just me having a rant you understand, how these sort of jobs just snowball in the total ballache department - my mum reminded me that the guys who put the boarding down cut a section in front of that area as a kind of inspection hatch about 2 foot square.

Brilliant I thought...however, the floorer who laid the Karndean floor put 5mm ply over the entire floor to give him a smooth base I guess. No worries I thought, I can see the screw heads, with the screws removed nothing really happened. It turns out that right over the inspection hatch the 5mm ply was glued down with enough adhesive to stop a rhino.

I've just spent a very 'enjoyable' day on my knees with a mallet and chisel trying to get this ******** ply off the flooring beneath, only to find that the inspection hatch is not perfectly square on one side but cut in a set of attractive angles which extend further under this ******** ply.

The other thing that made me larf hysterically was that on the section I did clear, the screws that hold the flooring to the joists had their heads rounded off when it was put down, so even if I could clear enough ply to expose each edge of the hatch, I'd never get it up because I can't undo the poxy screws.

I'm not happy....

Welcome to our world! Nobody thinks about the next man to follow and/or maintenance.

 

[thetcutkid]

You have my total respect