locating damp source

[diy_fun_uk]

in my BTL property there was a slight sign of damp 2-3 years ago on a section of wall within the lounge. it wasn't severe and by the time i visited the property it had dried up. however i removed paper from affected area, treated wall surface and re-papered. that seemed to sort it.

new tenant just in and they've advised of slight damp in same area. if memory serves me correctly i think both times this has been reported were preceded by really heavy rain and strong winds.

it's a ground floor flat and there doesn't appear to be any water running down wall from upper flat. the previous owner has, for whatever reason, pumped expanding foam (or something) behind the drainpipe that runs down the corner of the kitchen/lounge walls. i am wondering if this 'stuff' could be acting like a sponge, drawing rain water in for it then to be absorbed by the wall? or absolutely not the cause of my damp?

my other thought is could it be water from the drain? tenant advises when water draining there are soap suds seeping around the surface. could this be the cause? the wall does look crumbled in that area behind the drain.

see attached pics. any advice welcome. i'm thinking it might be a good idea to scrape the foam stuff out to let air in behind that pipe? note the foam runs from the height of the windows down to level of the lower outside window sill.













i'm wondering if it's coincidence that the damp appears to be roughly in the same area (height wise) as the foam stuff behind the pipe?

as i say any thoughts/ideas welcome. i'm trying to avoid getting stung for a £££ fix if the actual cause is easier/cheaper to resolve.

 

[foxhole]

The foam could be a main cause of the damp , have you checked the guttering, and the pipe, the gutter could be blocked causing it to overflow down the outside of the pipe, the pipe may also be damaged, hidden by the foam.Ensure your drains are clear.

 

[masona]

Just a thought, the pipe seems close to the wall therefore no air flow to dry any rain wetness lurking behind there? Could be driving rain into the corner is not helping but check from top to bottom external first and clear any blockage from wall to pipe

 

[JohnD]

the foam might be cavity wall insulation that has escaped through a hole in the brickwork

the hole might be the cause of water entry.

you can trim away hardened foam using a serrated knife.

Looking at your plan, the damp patch is on the other side of the wall from the kitchen.

tell us about the pipes, drains and sinks on this kitchen wall.

 

[foxhole]

Whats the overflow pipe at top of windows serving?

 

[diy_fun_uk]

thanks for replies all.

sorry not sure what the overflow at top of window is serving. yes if you're looking out the lounge window (the one on the right of the pics in my OP) from the inside the damp patch is to the right on a section of wall between the window and the door into kitchen, see white oval for approx area of damp:



looking from the kitchen side (other side of the damp wall) the damp section is where the tiled walls meet and continuing to the right as you look at the pic i.e. where the kitchen wall meets the lounge wall:



there are pipes as you'd expect under the kitchen sink, both copper ones serving the water and plastic serving the waste, which goes out below the kitchen windows and feeds into main downpipe.

there is no sign of damp under the sink, or leaking pipes etc. that all seems dry enough.

the tenant is going to keep an eye, tbh i'm hoping it's been a one off caused by certain weather conditions as happened 2-3 years ago however if it remains i'm thinking as a first port of call scrape the foam out and let air behind the pipe, checking for breaks in the pipe as well. if damp still remains it'll be over to the pros i suppose

any more thoughts welcome.

 

[masona]

Well if it's was me, I would undo all the down pipe, clean up any foam or bridging debris, dry it out for a couple of days, check all pipe for any slight blockage, could be some debris at the top over flowing the rain over the gutter running outside of the down pipe. Modify the down pipe with extended pipe wall brackets for better air flow behind the pipe and the corner wall or re-position the down pipe elsewhere.

 

[foxhole]

I don't think you need to worry about leaking kitchen pipework it would not explain the high damp levels, water does not climb walls.You can remove the foam from pipe by dragging a piece of wire down the back with a sawing motion.

 

[JohnD]

It's a flat, so there are probably pipes to, and in, the kitchen on the next floor.

The stain is curiously high though, rather as if there was a shower or boiler on the other side of the wall.

 

[ntb]

That whole thing looks bodgetastic. Waste pipe into drain pipe via a silicone sealant adaptor? The foam looks like someone has just bodged a hole. Take the pipe off, chop out the foam and make good properly.