Insulation for dormer houses

Kez100

We want to insulate in between the roof and our dormer plasterboard ceiling, very hard to reach areas! - hopefully without having to take the plasterboard down.

Anyone any idea what products we can use and where we would be best sourcing them?

Andy_Davies

Kez100 wrote: »

We want to insulate in between the roof and our dormer plasterboard ceiling, very hard to reach areas! - hopefully without having to take the plasterboard down.

Anyone any idea what products we can use and where we would be best sourcing them?

There is something you can get called Sempatap that sticks onto the existing ceiling but not sure how good it is.

Other than that the alternatives are take the ceilings down, insulate between the rafters with a solid board like Kingspan or Celotex and then use a insulation backed plasterboard for the ceiling.

Or take the roof off, insulate between the rafters with solid board and then put the roor back on.

We're currently trying to work out what to do with the attic beadroom in our Victorian cottage and there's no easy choices I'm afraid

Andy

Andy_Davies

Sorry product is actually called Sempatap thermal

savemoney

Found this for that product

http://www.mgcltd.co.uk/Products/Thermal_and_Acoustic_Insulation/

plumb1_2

You could also have insulation blown-in through 25mm dia holes.

Kez100

Thanks all. We have seen the blow in stuff via companies which don't tend to come up well with people like Watchdog! Can we do 'blow in' insulation as a DIY project or how would we go about choosing a reliable company?

littlesos

We are just insulating our dormer bungalow roof. The only way we could do it efficiently was to pull the ceilings down though. We are using celeotex board, but as it's a bungalow with purlins, our rafters are only 75mm deep. As we have to have a 50mm airgap between the felt and the insulation we've only got space for 25mm insulation!

In our case we have increased the thickness and lost some interior space. As we are not building/converting we don't have to meet current building regs, so we are getting as close as we can, without compromising the upstairs space.

Andy_Davies

littlesos wrote: »

We are using celeotex board, but as it's a bungalow with purlins, our rafters are only 75mm deep. As we have to have a 50mm airgap between the felt and the insulation we've only got space for 25mm insulation! .

You need a 50mm airgap in a ventilated roof, if you had something that was breathable under the tiles e.g. Tyvek, then you can have a smaller gap.

littlesos

Andy_Davies wrote: »

You need a 50mm airgap in a ventilated roof, if you had something that was breathable under the tiles e.g. Tyvek, then you can have a smaller gap.

Yes, but to change from the felt to a breathable membrane would involve taking the entire roof off, and that is a step too far!

Andy_Davies

littlesos wrote: »

Yes, but to change from the felt to a breathable membrane would involve taking the entire roof off, and that is a step too far!

That's what we're contemplating at the moment but then we've got no membrane under the front pitch of our cottage and aren't quite sure what's under the back.