Can anyone advise on this damp issue….

[martin1959]

Hi

I blocked up a door into my daughters kitchen last year. The wall was thick, so built up two block walls with a 50mm air gap between the two block walls. The internal blocks were plastered, and the external blocks rendered. I fitted a tile sill and we had a new window which sits on the rear of the tile sill. The walls were rendered up to a wood frame, which was removed when the window was fitted. The external render has had three coats of sandtex external paint, and the sill has had a couple of coats of tile paint, and has been silicone sealed all around the window.

On the inside the walls were plastered after the window was fitted and all around painted with a matt emulsion. After six months or so, the paint has started bubbling on the plaster and we seem to have some fungal growth. I really cannot see where the water could be getting in. I have looked behind the kitchen cupboards under the sink as I thought it could be ‘rising’, but the paint behind the cupboards under the sink is fine.

Any thoughts welcome……..

 

[Sonic70]

Looks more on the right side for some reason. Can you easily take off the wooden internal sill to look down cavity. Are all the pipes under sink sound.

 

[martin1959]

All the pipes seem fine. None go in the wall they are surface mounted so if there were any leaks it would come down in or behind the kitchen unit.

The window sill on the inside is quartz to match work top and not easily removed.

At one point I did wonder if it was condensation from the kitchen but as it is only on one area, dismissed it.

 

[Sonic70]

Is it wet like that all the time or does it dry out and come back. I wonder if it is wet below the plaster. Is there insulation in the cavity there, is there insulation in the rest of the kitchen walls. It could be a particular cold spot in the kitchen walls and be condensation maybe, just guessing.

 

[martin1959]

It dries out in dry weather and comes back after rain, but I cannot see anywhere on the outside it could be coming in.
No cavity insulation between the two breeze block walls under window just a 50mm air gap. No other insulation as all walls are solid brick 1930’s house

 

[Sonic70]

So in the rain is it possible it's coming down the cavity. Also just looking at the bottom left corner of outside of the window could it be getting in there. Plus I'm not sure if the window sill on outside looks right to me where would the sil drain holes be. Just a diyer throwing out ideas.

 

[PotatoSoup]

Hiya, could it be a salt problem? I'm only a DIYer but just wondered- here's an article that's good on salt... https://www.davidkinsey.co.uk/pages/the-effect-of-salts.php