Water mark on wall

[dalboy]

Hi all

not sure if this is the right subforum to post.

i have a loft conversion with en-suite. been fine for years.

went on holiday the other week and came back and saw a few inches on the wall the paint had slightly bubbled. i rubbed it and the paint came away, and looked slightly brown mark on the wall although i thought this may be the wall itself. it was dry not wet.

we rubbed the wall down to remove any more loose paint and then tried covering it up with paint which hasnt worked. im now thinking this is a leak? there is a radiator outside the en-suite and the pipe from that goes behind the wall where the leak is so could be that although hard to tell.

central heating and the above radiator is working fine (no sign of leaks), no funny noises, no water issues in the en-suite, no visible leaks in the en-suite either. i keep checking the wall and its completely dry.

any ideas guys?

Picture attached of where you can see we have tried to paint over. (the raised part is from the brush strokes!)

thanks!

 

[omega015]

It could be from the wall outside that's letting water in between the bricks or maybe the guttering backing up and running inside the cavity or a loose tile and water running down the felt etc.... The stain wont go if the original source of the damp isn't eliminated, and once it is you might need some stain block to seal it so you can paint back over.

 

[dalboy]

It could be from the wall outside that's letting water in between the bricks or maybe the guttering backing up and running inside the cavity or a loose tile and water running down the felt etc.... The stain wont go if the original source of the damp isn't eliminated, and once it is you might need some stain block to seal it so you can paint back over.

Thanks for your reply.

This wall is not externally facing, its between the en-suite and the bedroom. Sorry should have stated that.

a colleague of mine suggested it could be condenstation build up around the radiator pipe from the cold weather when i was on holiday and the heating wasnt on, but said its probably not an actual leak and to keep an eye on it and see if it gets wet or increases in size. thought this sounded quite viable - thoughts?

thanks!

 

[omega015]

Could be that or condensation from the cistern, give it a while to full dry out then sand and give it a coat of paint and see how it goes. If the stain comes through then try some stain block paint.

 

[oldbuffer]

Had exactly the same on an internal wall between bathroom and bedroom. Turned out to be tiny leak from shower inlet pipe tracking through breeze block wall.

 

[dalboy]

Had exactly the same on an internal wall between bathroom and bedroom. Turned out to be tiny leak from shower inlet pipe tracking through breeze block wall.

Thanks, the shower cubicle is On this wall but in the corner and piping is on the other wall so by logic not sure if the shower piping will reach to where the issue is but you never know.

Was your wall mark wet / get larger in size?

 

[oldbuffer]

1. Mark was very slightly damp to the touch.
2. There are actually two marks (I'm looking at them now) Both grew from 20mm diameter (when first noticed) to about 400mm x 30mm.
3. Changed shower, stopped leak and marks stopped growing.
4. Will get round to decorating soon, but no rush as only happened five years ago!