Mould on ceiling of bay windows.

mandy47

Looking for advice.
I have 2 large bay windows. Outside covering is lead. They're not an issue until winter when I have a black mould problem.  The kitchen one is the worst. The paint is actually peeling off. 
I use an extractor fan in the kitchen when cooking. I run a dehumidifier daily. When weather is better I open the window instead of dehumidifier. I clean the off mould with appropriate stuff a couple of times a week.
Bedroom has a dehumidifier and open windows when weather is suitable. 
But it isn't working. Looks awful and is unhealthy. Had the roof checked and there are no issues. It's fine in warmer months. 
Any suggestions on how to prevent it, cover it and stopping it coming back.
It's  a 1930s property with external insulation , central heating and wood burners. It's not a cold house. 

FreeBear

mandy47 said: Any suggestions on how to prevent it, cover it and stopping it coming back.
It's  a 1930s property with external insulation , central heating and wood burners. It's not a cold house. 

Have you checked to see if there is any insulation above the bay ceiling ?

This is one area that is difficult to access, so rarely gets any insulation. I have a pitched tiled roof over my late 1920s bay that never had any insulation until recently. Due to the construction, gaining access through the tiled roof would have been a major undertaking. Ended up removing the old lath & plaster ceiling and putting in around 200mm of loft insulation - If I were to do it again, I'd probably use 100mm of loft insulation above the joists and 75mm of Celotex between...

Depending on how much window frame you have exposed at the top, a layer of insulated plasterboard would help. You'd need to give some thought to fixing curtain rails securely (blocks of wood screwed to the ceiling joists and pocking through the PB perhaps).

mandy47

Thanks.
There's no curtain rail in the kitchen and the window goes right to the ceiling. 
Bedroom is fitted to ceiling but with tiny fittings for light weight curtains.  
You're probably right about the insulation.  It is very cold to the touch. I'll need to rethink on a way to add insulation. 

ThisIsWeird

After going on at great length on here about ventilation being the key, and chuffed that I only have small lines of condie on my sitting room window panes, I discovered extensive mould spots over my bay window ceiling this morning that I'd simply not seen before.

It'll be as FreeBear says - as it will be in mine; little or zero insulation in that ceiling void above the bay.

Two solutions - one is to gain access to the ceiling void and sort it - but who the hell wants to do that in this weather! - and the other is to line the underside with some form of insulation.

Interestingly, there's a current thread on here about 'Wallrock'-type insulated wallpaper, and this could be ideal as it should be easy to add, and also simple to blend in. 

Could we have a photo of your bay ceiling, please?

My solution - I killed it with a damp cloth and mould buster, 'cos I'm lazy.

FreeBear

mandy47 said: There's no curtain rail in the kitchen and the window goes right to the ceiling.

There is usually an inch or two of frame showing between the glass and ceiling. Most unusual to have glass all the way up.

twopenny

I have a 24yr old house and the bay has no insulation I realised.

Just had a word with builders and owners next door doing an extension next door if they had a small amount left over could I have it.

Yup it's going to be a real bad temper making job with my tiny joists but I reckon I (or my agile odd job guy) can do it as least to make it better than it is. In an old house it should be easier as the roof timbers will be larger and easier to crawl on.

You and any family are breathing out moisture and is lifted upwards by the warm air heating and when it hits a cold spot it will cause mold.

This has helped you find the cold spots that need dealing with so in a weird way, a good thing.