white mould in loft

jackieb

We don't keep anything in our attic so rarely go up there. My OH went up a wee while ago and noticed white mould on the underside of the roof. We did have it insulated (for free, from someone who came round the door, said it was from the government..). So we have about a foot of insulation up there now as opposed to the 2-3'' we had before. I did look it up and know the mould can be cause by inadequate ventilation because of the age of our house meant it didn't have a breathable membrane under the tiles (or something like that!)

We are going to get a roofer in to get a price to get vents installed but my question is, would white mould in the attic cause black mould in a bedroom below? It hasn't always been mouldy and I would say it probably started around the same time the insulation was added, but I can't swear on that. We painted the bedroom a few months ago and the mould has came back despite having bought a (good) dehumidifier which is on most of the time when someone is in the room - and it collects about 1-2 litres of water a day.

Also, the white mould in the attic is only on one side of the roof and that's the same side as the bedroom with the black mould.

phil24_7

I may be that the insulation has been laid right up to the eaves stopping air flow though the roof space. Make sure it stop short of this and see how things go.

Regards
Phil

Norman_Castle

This could be condensation in the loft dripping onto the ceiling.

phil24_7

Sorry, I missed the second paragraph...the real question! The extra insulation in the loft has made it more prone to getting condensation.

Try to air your house out more as well as heat all of your rooms regularly. Make sure you close bathroom/shower doors when they are in use and that you use room extractions in these as well as the kitchen if possible. Make sure the extraction has an overrun setting at that they are rated high enough for the volume in the room. Try not to dry washing in the house. If you have to, put them in a room, close the door and use a dehumidify with a clothes drying setting.

This along with clearing your eaves of any insulation to improve airflow through the roof should sort your problem out.

Regards
Phil

jackieb

Thanks to you both.

Norman_Castle wrote: »

This could be condensation in the loft dripping onto the ceiling.

This is what my husband thought it might be.


Yes, I open windows and heat the house. I bought 2 dehumidifiers last year (one for drying clothes downstairs) and the other one for the room with the damp. All the other rooms in the house are fine apart from that one room so we're thinking it has to be something to do with the thicker insulation.

Smiley_Dan

It's *not* the thicker insulation that causes the problem, directly. It's *possibly* the fact that the insulation is working more effectively that means the surfaces in the cold loft are at dew point, leading to condensation. But that's not a reason to remove any of the insulation.

I would suggest ventilating the loft a little more. As above check that the eaves aren't blocked - there should be 50mm clearance between the insulation and the sarking. You might want to use rigid insulation here to get you better insulatory value given less depth. Another thing to try is this trick: https://www.youtube.com/watch?v=EweV6fptFV4

The other thing is to consider any holes where air is getting from the heated envelope into the loft space. Any downlighters? They should be made air tight. Service penetrations, the loft hatch etc etc.

jackieb

Smiley_Dan wrote: »

It's *not* the thicker insulation that causes the problem, directly. It's *possibly* the fact that the insulation is working more effectively that means the surfaces in the cold loft are at dew point, leading to condensation. But that's not a reason to remove any of the insulation.

I would suggest ventilating the loft a little more. As above check that the eaves aren't blocked - there should be 50mm clearance between the insulation and the sarking. You might want to use rigid insulation here to get you better insulatory value given less depth. Another thing to try is this trick: https://www.youtube.com/watch?v=EweV6fptFV4

The other thing is to consider any holes where air is getting from the heated envelope into the loft space. Any downlighters? They should be made air tight. Service penetrations, the loft hatch etc etc.

No, no downlighters but we are going to see about getting vents put in. I'll get my OH to check if there is any clearance though, thanks.

I don't have any felt like in the video, just the bare boards.

PeppaPig123

jackieb wrote: »

Thanks to you both.



This is what my husband thought it might be.


Yes, I open windows and heat the house. I bought 2 dehumidifiers last year (one for drying clothes downstairs) and the other one for the room with the damp. All the other rooms in the house are fine apart from that one room so we're thinking it has to be something to do with the thicker insulation.

Hi Jackie,

My post won't give you the information that you are looking for but I am interested in your dehumidifiers.

You mentioned that you bought two dehumidifiers. May I ask which brand and model they are and what you think of them?

Also which one do you use for drying clothes indoors?

Thanks,

Peppa

jackieb

PeppaPig123 wrote: »

Hi Jackie,

My post won't give you the information that you are looking for but I am interested in your dehumidifiers.

You mentioned that you bought two dehumidifiers. May I ask which brand and model they are and what you think of them?

Also which one do you use for drying clothes indoors?

Thanks,

Peppa

These are the ones I have. I bought one at first for my son's room, then bought another for downstairs for drying clothes as I don't have a dryer. They have a filter that needs vacuumed, an easy job which I do about once a fortnight. There is a clothes drying setting on it. They're easy enough to move from room to room as they have the handle on top. And it turns itself off if the container gets full of water.

I've used it if doing a lot of cooking when the windows steam up and they clear very quickly when I switch it on.

When I decided to buy a second one I just went with the same one I already had as I liked it. There might be cheaper models that do the same job but I just went with the reviews on this one. There is a slightly cheaper model that is a 12L but our Argos only had the 14L in stock and I wanted it there and then lol

http://www.argos.co.uk/beta/static/Product/partNumber/3998250.htm

I also turned it on when we painted one wall of the kitchen red. The water in the container was a very pale pink lol

Zola.

I have noticed this in our attic just at the weekend. We got the attic re insulated and now there are a lot of white spots on the ceiling felt.

On our home buyers report it did say we need vents for air flow, how do we arrange this? Our house is an older semi detached, from the 60s and doesnt have these.

jackieb

Zola. wrote: »

I have noticed this in our attic just at the weekend. We got the attic re insulated and now there are a lot of white spots on the ceiling felt.

On our home buyers report it did say we need vents for air flow, how do we arrange this? Our house is an older semi detached, from the 60s and doesnt have these.

I was thinking it would have to be a tiler/roofer. I was going to get quotes from some. Our house was built in 1977 and I did read that houses after this (can't remember what year though) had a breathable membrane that was under the tiles but the membrane before that date wasn't, hence the need for vents in the older houses.

They never told us this when we got the insulation installed though. So we've had 2-3 years of mould growth up there as we were oblivious!