mould

paul127

Have a problem with mould .The house is a 2000 square foot selfbuild airtight dormer (not fully airtight yet eg sewer pipes trap door doors at eves and under front and back not sealed) . The make up is 150mm rafter +50mm batten from out side slate 2by1 batten breathable felt 140mm fiberglass (ridge type) airtightness membrain 50mm board .The plastering just finished(upstairs done during the could spell) .The problem seem to only be upstairs there is very bad mould on the window boards(MR MDF) and temporary door liners there is also small spots of mould starting on the ceiling and walls . The roof is vented 5 slate vent and plenty of vents in the soffit . Is this normal for airtight houses that were plastered during the cold spell and what can i do to stop/kill the mould .Will the HRV and heating when on solve this ????

FesterBeatty

You say it was plastered during the cold spell...? You typically need absolute minimum of 5 degrees and rising for plaster, similarly with blockwork mortar/concrete etc - no wet trades in that kind of weather effectively. But, its done now - so what's the wall construction - is it timber frame? Cavity? Hollowblock? Solid Block? Drylined?

tred

Paul are you daily airing the house. As in opening windows and doors!.

creedp

tred wrote: »

Paul are you daily airing the house. As in opening windows and doors!.

I think this is a really important point particularly in cold weather. When my house was plastered inside, particularly upstairs, I would find that if the builders hadn't left them open the windows would be dripping with water internally for a couple of weeks after the plastering was complete. I used to have to go around and open all the windows as the builders used shut them to keep drafts out while they were working!

clint_eastman

I have the exact same issue on my window boards at the minute (not on walls though), I'm not overly concerned, heating on now, window boards to be cleaned/sanded/painted once the house is properly up temp wise. Not sure about your walls, but "I" would not worry too much about this. As the other have said, try and keep the house aired until the heating comes on.

paul127

The wall build up is cavity 150mm pumped with 50mm board internally,but all of the mould is upstairs where there are only 3 gables. The windows are left partially open in the locked possion all the time and opened fully once or twice a week when i am there,Is there anyway to treat this mould ?????

tred

paul127 wrote: »

The wall build up is cavity 150mm pumped with 50mm board internally,but all of the mould is upstairs where there are only 3 gables. The windows are left partially open in the locked possion all the time and opened fully once or twice a week when i am there,Is there anyway to treat this mould ?????

Its mildew, and your going to struggle to avoid it. Have you thought about bringnig in a dehumidifier. Have you tried to clean it frmo the window boards, with a warm cloth?. A bit of bleach might do it as well.
3 builders told me, leave the windows up stairs open all day. When you pour the floors ,even more moisture