Ceiling and side wall flaking slightly

[Lk1980]

Hi forum members
Merry Christmas and hope you all had a good Christmas celebrations. Feom.past few months i have had a this strange peeling by the ceiling and on the side wall. Its been a year i had this extension built. No problem anywhere else. It does not look like damp but i maybe wrong. After this occurred, i had asked the builder come in a do a bit sealing with silicone where roof and the guttering to be 100% sure that there ia no water ingress from anywhere. Last few months back, i have also applied stormguard masonry cream all over by the wall just to be sure.

Can someone advise if this is a low quality paint / plaster or a sign of something more sinister lurking

 

[Wayners]

Condensation mould. It's a cold spot and moisture forming on surface causing paint to peel plus I can see black mould.

If it was a water leak it would looked different with staining and shaped where water has run. Maybe I'm wrong but worth getting a camera and putting in cavity to look.

Make sure ceiling has insulation as that can be missed at edges. That would be what I'd look at first

 

[Lk1980]

Condensation mould. It's a cold spot and moisture forming on surface causing paint to peel plus I can see black mould.

If it was a water leak it would looked different with staining and shaped where water has run. Maybe I'm wrong but worth getting a camera and putting in cavity to look.

Make sure ceiling has insulation as that can be missed at edges. That would be what I'd look at first

Thanks Wayners. There is a full insulation the ceiling (I know it because the building control did not allow the builder to close the roof before this was inspected by them. I can't remember if there is an insulation between the cavity of the parapet wall. I remember builder telling me its the rebut no photograph in my building progress library. I guess only way to find out is by removing the coping stone and getting the builder put it back again and re point it.? Unless there is another way to check ny drilling a pilot hole in the pointing from outside?

 

[Wayners]

I found many places with no insulation right at the edge and even when there was the corner was exsposed enough to get cold air blowing against the loft side.

Insulation barrier ( rafter roll) is often fitted to keep air gap.

Problem is the room edge can still be cold. All needs to be tight but even then there is not enough insulation at the edge to stop the cold spot.

Corners and room ceiling edges show signs of mould like yours. I've got it in all four corners of my house, but no other areas. I treat every spring. I can't stop it. See picture...
I also run two dehumidifiers in the evenings. That's stopped window condensation.

I might be wrong but I think that's condensation forming on surface in your corner

 

[^woody^]

Yes, condensation due to a thermal bridge or poor insulation.

 

[Lk1980]

Thanks woody and wayners. So what is the solution. Wondering If I ask the foam company to drill the pilot holes and push the foam through?

 

[Wayners]

Foam may block airflow. Need to look at the other side to confirm it's not water getting in. We think not though.
Also look to see how the insulation is placed. Then decide

 

[^woody^]

You can't guess. It may be something as fundamental as some roof timbers fixed there or the way the wall is built, and no amount of injected anything will stop it.

Can the other side be seen, or exposed?
What is actually there?

 

[Ivor Windybottom]

It does look like condensation.

It also looks like it was painted with full-strength emulsion onto bare plaster and/or while the plaster was still wet. Try scraping from one of those flakey edges, see how much you can peel off.

It also looks like there's at least one crack.

Possibly three unrelated problems, all in one corner.