Black mould - even though rooms are ventilated.

[piper64]

I've read about how to make sure the room is ventilated and I recently unblocked the external airbricks that Millfold kindly filled with silicon when they alledgedly installed cavity wall insulation.

It has made no difference.

The worst of the black mould is where the ceilings upstairs join the walls. Our house was built in 1946 and it was considered a good idea back then to put the ceiling very high into the loftspace, thus creating a slope where the ceilings meet the outside walls.

The loft is wel insulated, but it is not easy to see what is stuffed, or not, in the gap between the roof felt and the upstairs ceilings around the outside walls.

My logic says that this gap should be left open, but then this is an area where cold air on the loft side of the plasterboard is causing condensation on the other side of the plasterboard, in the upstairs rooms.

Should this sloping gap be insulated or left?

 

[pinenot]

To answer your question directly, the answer is both.
First off ventilation from the eaves should always be retained to the loft area. But in today's environment to insulate the entire ceiling area is also paramount.
How is this achieved... View media item 60919 This is a resolution on a previous post I made and I feel is suitable for you...pinenot

 

[piper64]

Thanks pinenot.

I gather that I don't need to add new plasterboard as in your diagram, but just need to multifoil the existing plasterboard in the loft?

Erm, what's multifoil?

The eaves and soffets are old uPVC and have no obvious ventilation such as slots or grills, so another job I'll need to do is to replace them with vented ones. It could be easier to get to the sloping plasterboard in the loft from the outside at the same time?

 

[foxhole]

You need even more ventilation, unless you dry clothes indoors, in which case you will always have mold.

 

[piper64]

I may as well take the windows out altogether then. They are on the latch 24/7, we only dry clothes in the conservatory, which is then closed off from the house. The tumble dryer is vented to outside and is located in the outhouse.

The mould is confined to the slopes on the celing, so what further ventilation would you suggest?

 

[big-all]

another thing to check is condensation in the loft may be running down the timbers and grounding on the plasterboard ??

 

[piper64]

Good point, so I just went up and can't see any condensation on the rafters.

 

[pinenot]

Thanks pinenot.

I gather that I don't need to add new plasterboard as in your diagram, but just need to multifoil the existing plasterboard in the loft?

Erm, what's multifoil?

The eaves and soffets are old uPVC and have no obvious ventilation such as slots or grills, so another job I'll need to do is to replace them with vented ones. It could be easier to get to the sloping plasterboard in the loft from the outside at the same time?

http://www.planningportal.gov.uk/uploads/br/multi-foil-insulation_july2005.pdf ...pinenot

 

[piper64]

Thanks, it looks like good stuff.

I've looked it up on the web and it seems to be best applied to the inside of the roof tiles and battened down? Given the very limited space between the ceiling plasterboard and the roof tiles, that's not possible.

Have I got the wrong material?

http://www.roofingsuperstore.co.uk/product/insulation-2/other-leading-brands/alumaflex.html

 

[pinenot]

No you've got the right material alright you just need a proper way to install it. Could you provide a sketch ? ...pinenot

 

[piper64]

Not sure how to get a sketch onto the thread, but essentially if I was in the loft and managed to squeeze into the space where the roof timbers rest on the wall, I will need to insert a sheet of this material resting on the plasterboard. The other side of the plasterboard is the bedroom ceiling.

 

[foxhole]

I may as well take the windows out altogether then. They are on the latch 24/7, we only dry clothes in the conservatory, which is then closed off from the house. The tumble dryer is vented to outside and is located in the outhouse.

The mould is confined to the slopes on the celing, so what further ventilation would you suggest?

Moisture from drying washing anywheere in the property will find it's way upwards to roof level.
Mold is formed when spores settle on cold damp surface , almost impossible to prevent cold surface somewhere in a property so good constant air movement is the only way to prevent mold.
Ideally every room should have a vent and bathroom and kitchen mechanical vents used whenever occupied.

 

[big-all]

Good point, so I just went up and can't see any condensation on the rafters.

mold develops over weeks so the condensation may have been weeks ago
look for stains down the roof timber that may be caused by water damage ??

 

[piper64]

Hi chaps, thanks for the replies. A vent in each room would be drafty wouldn't it? As I say, the windows in the upper rooms are always latched 24/7, which must be at least equivilent to a wall vent?

I understand that damp washing causes condensation, but it isn't in the main house, it's shut away in the conservatory which is closed off.

Once I get the new vented eaves put up it may help, as there is little else I can do except not wash any clothes.


On a seperate but linked issue, I have noticed in the past that a corner of the bedroom on an outside wall can get freezing cold in the winter and wet to the touch. As there are often dry clothes on a rail there, a small amount of grey powdery mold has formed at times, rarely. I am planning to put a wardrobe there soon, so as this is already a problem area, what's the best way to go about that?

 

[big-all]

unless the conservatory is vented to the outside the moisture will transfer throughout the house every time you open the door rising with the heat to upstairs and condensing on the coldest surface