Anyone seen anything like this before?

10 Aug 2011
Reaction score
United Kingdom
Had my walls recently skimmed, put a mist coat on then 2 coats of dulux vinyl matt emulsion on, about a month later, damp marks started coming through. the picture with the hole is where the waste pipe is boxed in, i cut a hole to check for leaks and everything is dry?? so a bit confused. the other picture is of a internal wall, There must be moisture present on both sections. as when i put an electric heater on the marks it disappears but reappears within a few hours. im not exactly sure if it is damp as there are dry spots in the middle of the patches. the skim was left to dry for about a month so dont think its that, anyone have any ideas????

View media item 36444 View media item 36445
Sponsored Links
cant see the situation properly but you may need an air vent in the void that houses the pipes. if you block off a chimney stack you need an air vent in the wall so could be the same here.
Hi, i cut the hole in and marks were still there, exactly the same type of patches on the other wall too and that is a solid internal wall(joined onto a external wall) so dont think its condensation, may be wrong though
Sponsored Links
Yeah, this is the ground floor, and nothing obvious is standing out, the rooms above is dry, never had issues with damp in there before
That's on the chimney breast, so logically you need to get up there and check the pointing / flashing as the first port of call.
Any water pipes in there? If so might it be water condensing on the pipes, and if the pipe is touching the plaster board it might be soaking through.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local