black mould/marks on ceiling

[ispentitwithyou1]

Hi guys,

Wondering how to proceed.... Just spent our savings on new windows and doors and now black marks have appeared on the kitchen ceiling... the ceiling looks like it is bowing but I think only very very slightly and it may have been like that anyway.... Above is a fairly old shower cubicle. What could it be??

Your new windows will be a lot less draughty than your old ones. This means all the damp air will stay in the house and condense wherever is coolest and cause mould.
Either leave some of the windows on trickle or open them wide twice every day for half an hour.
Also make sure you use any extractors when cooking or showering, and don't dry washing indoors or anything like that.

I agree it could be that the new windows are less draughty but the bowing ceiling is a worry. Are you sure it isn't a leak from the shower? Are there any brown marks on the ceiling too? One way to distinguish between condensation and a leak is to tape some plastic over the damp area having first cleaned the mould away. Leave it a few days and if the plastic is becomes damp on the ceiling side, it is a leak, if it is damp on the other side, it's condensation (I think I nicked that from someone on MN - it is a very useful tip though ).

Thanks so much guys! Should have said,windows haven't been installed yet but excellent point about extractor fans,there's not one in kitchen or bathroom and will try that tip tomorrow x