Mould on raked ceiling

[treesurg]

Hi
We have been having a problem with mould on our raked ceilings (see pictures). This is affecting 2 bedrooms at the front of the house and the bathroom at rear (corner room).

The property details are-

Built in 1930, semi detached.
Solid brick construction.
Pitched roof.
150mm of loft floor insulation 2016.
150mm external insulation (walls) in 2019.
Attic window and vents put in on both sides of roof early 2020.
Double glazed windows 2019.
One radiator in each room and all rooms vented.
Extractor fan in bathroom.

The mould is affecting the two front rooms (at the raked part) which are south west facing and bathroom north east facing. It has become much much worse this winter and we can clean it with mould killer and it’s back in less than a week.

Any help/advice would be appreciated.
Thanks in advance.


Read more: https://www.diynot.com/diy/threads/mould-on-ceiling-eaves.356096/#ixzz6igg1nvhJ

 

[^woody^]

Mould at these areas is typical, and due to the cold bit of roof above it.

It will need insulation either above or below that section of ceiling.

 

[treesurg]

Thanks. Is there any reason it’s worse this year? Was it the extra insulation in other areas? We are surprised because of the extra venting put in.

We have located a contractor to come and look but they all have 3-4 month run in time. What’s the best way to deal with this problem in the interim?

 

[^woody^]

Thanks. Is there any reason it’s worse this year? Was it the extra insulation in other areas? We are surprised because of the extra venting put in.

We have located a contractor to come and look but they all have 3-4 month run in time. What’s the best way to deal with this problem in the interim?

The conditions for and causes of condensation are a fine balance, and it only takes a slight change for the balance to be tipped. So you can go for years with no condensation then a change in one of the seasons or building or occupancy pattern has a knock on effect.

Likewise for adding insulation somewhere, all that does is shift the condensation to the next cold surface. The actual humidity has not changed, but the conditions for it have.

Also with venting. Its common advice (sometimes bad advice) to put a vent in, or open the windows and suchlike. All that does is allow cold moist air in, so may not be the best thing to do. It only works when done in conjunction and in consideration of other measures.

With almost all condensation issues, you need to look at the moisture you are producing and how that is being managed (or extracted). Some times buildings can cope other times they can not. Just make sure you are doing all the right things for dealing with excess moisture, and using heating and ventilation appropriately.

Wipe any mould off now as it will just keep spreading.

 

[treesurg]

Thank you for getting back! Had a feeling the vents weren’t helping things.