Extension (flat roof) insulation

[ACOperson]

Hi all,

have got a 1st floor flat, building is a larger style 2 up 2 down with a single room extension at the back done many years ago. Extension has an un-insulated thin flat roof and 3 external walls, and a sodding great draughty sash window. Room gets really cold in winter.

We're doing a bit of work incl draught proofing window & increasing radiator size to proper for the room and I was wondering what the best way of insulating this roof is? The ceiling is not that high so traditional fibreglass loft-type type insulation is too thick.

Anyone know of any thin material which may be suitable (ie good insulation properties & less than 1" thick)? I had wondered about some kind of metallic foil under plasterboard but not sure how good this would be...

Thanks in advance.

 

[freddiemercurystwin]

I've specified this before, complied with regs, builder installed it no probs

http://www.tri-isosuper10.co.uk/index.htm

 

[Fluffster]

Make sure you ask your local building control first mine (greenwich) would not allow as they say it does not do as it says on the tin apparently.
Pete

 

[jeds]

You don't need building regs for retro-fitting so that shouldn't be an issue unless you are carrying out a major overhaul.

Tri-iso would be easy to use in this situation but controversy rages over how good the stuff really is. Problem is that it doesn't perfom well in the British Standard test for insulation products - known as the hot box test. It did ok in other real-life tests so was initially granted a Building control licence for a year. But then some other tests cast doubt on those tests and the licence was not renewed.

The situation now is that it can only be used for building regs work if it is installed in conjunction with standard insulation products - which slightly defeats the object if you ask me?

If I were you I would stick a thermal laminate plasterboard to your ceiling. This is insulation foam bonded to plasterboard so you get a finish you can decorate straight on to. Lafarge do them in 30, 40, 50 and 60mm. Go for the thickest you can accommodate. They also come with different grades of insulation. Thermalcheck K is the best.

 

[ACOperson]

Thanks guys