I had my bathroom plastered and they filled in a fairly shallow chase where shower pipes used to be on an an external wall. The room died out fairly quickly except these 2 areas. Its been over 4 weeks and the 2 areas dont look any different than they did 2 weeks ago. Im not bothered about waiting but im conserned that there dont seem to be any sign of progress and sometimes it looks like it gets worse. By the evening it looks like its got dryer but then the next morning it looks wetter. Is this normal. Any help?
Strange thing is, on the 'before photo' u see an old air brick area that i bricked up that too was bonded and skimmed and the chase wasnt much deeper. But for some reason the bricked up area has dried no problem.
Generally with a solid wall you use a cement based undercoat plaster which holds back any moisture permeating through a solid single skin wall. Can you spot anything in the other side that might be letting moisture through, cracks in render or missing pointing etc. Any heat on in the bathroom?
Outside wall is rendered, dont recall any noticeable cracks. No heat in bathroom as the rad needs to be fitted after tiling. However, due it sometimes getting worse ive on and off used a dehumidifier and a small heater on the lowerst setting to take the edge off.
What's the guuttering like outside where damp patch is, any leaking joint, blocked gutter causing water to overflow & make wall damp, even getting behind the render.
I have no guttering above the area as i have a flat roof. Definatly not a pipe leak as i removed the old shower pipe and replaced with a pipe that goes up halfway to the mixer as seen on photo. This new pipe isnt connected up yet either no mains water near ths area. Do you think its worth sticking up some plastic sheeting to the outside wall to block out any possible moisture??
Is the plaster actually damp or could it be stained, you tried a damp meter, also what's condition of flat roof, possible leak allowing water to find it's way down through cavity to inside wall.
Looks like it needs to dry out to me. I guess it's warm with heating on? Air flow will help so open window In the day. Maybe there was damp in wall from the bathroom so that's slowing it up. Put a pencil line around damp so you can monitor drying. May take another 10 days I guess...
Given that it is a vertical "damp patch" and that is the orientation of your pipes, what about condensation? Are they insulated? It springs to mind given that you say that it seems to improve towards the end of the day and is worst early morning given that they will be at their coldest overnight- praticularly as it is a single skinned wall.
I wonder if it just needs more time to dry out, the thickness of the plaster could mean it will take quite some while.
Thanks for your input bu there are no pipes there anymore. Its was the chase where the pipes used to be thats been filled in by the plasterer
If it doesn't dry soon might be worth cutting the patch out again and investigating. If it is a leak leaving it may cause issues elsewhere