Insulated Loft Board

SargentDuck

Hi,

I was looking at buying some insulated loft board in B&Q, currently €16 a board (each board is .4 m2) and I was wondering two things.

1) anyone ever use this and have positive/negative feedback?
2) seeing as I already have loft board up there, just not insulated, has anyone ever heard of just buying the insulation for underneath and just laying the board back on top again? Basically the insulated loft board just looks like very compressed styrafoam (I'm sure it's not through with some chipboard on top!

Thanks,
Niall.

650gs

Go to a builders providers and buy the 8x4 sheets or 150mm fiberglass and save yourself a few hundred euro

SargentDuck

I had planned on running 100mm of roll out insulation underneath the loft board, but still I want to bring to over all debth to + 200mm or equalivent.

Putting 150 mm underneath and then putting the loft board on top of it would just compress it no?

Thanks,
Niall

gaelicyoda

SargentDuck wrote: »

Putting 150 mm underneath and then putting the loft board on top of it would just compress it no?

Yes, it would - compressing either fiber glass or rockwool greatly reduces it's effectiveness.

Best thing you could probably do is pack in between the rafters underneath your boards with insulation - so you're going to be limited by the depth of your rafters (assuming you don't want to build them up?).

This insulated loft board you're describing though doesn't sound that great to me... whatever that insulation is that's bonded to the back would need to be as rigid as the chipboard in order to take weight (and not compress/cave in at the points that the rafters intersect it underneath). Did it say what type that insulation was? I know polyiso wouldn't be able to take any weight, so it's not likely to be that, and any insulation that's needed more for it's rigidity that it's low thermal conductivity is not as likely to be much good but without knowing the product, I could of course be wrong on that.

paddy147

19-20 euro for 1200 x 600mm Xtratherm insulated loft board in a good few builders providers

Tow

I was told these should not be uses unless your ceiling is foil lined plasterboard, as the boards dont breathe allowing condensation to build up.

SargentDuck

gaelicyoda wrote: »

This insulated loft board you're describing though doesn't sound that great to me... whatever that insulation is that's bonded to the back would need to be as rigid .

Hey,

Yeah it's pretty rigid alright. I have a photo of it, but missed the name! It's saying it has an R Value of 3.63...

I had thought of building up the lats to allow for more insulation, but given the price I was thinking this would just be a cheaper option.

SargentDuck

Here is the photo of the stuff I was looking at...

gaelicyoda

SargentDuck wrote: »

Here is the photo of the stuff I was looking at...

Hmmm... I might be wrong so in that case.

Blown rockwool would have an R-value somewhere between 3.1 and 4.0, so this product would seem to fall in that range too. If it's rigid enough, then yeah, I might go for it.

Be careful though - are you planning on storing heavy objects on top of it or anything? I just get nervous when it's not timber on timer in terms of support or load bearing. Maybe I'm just cynical though :-)

Boiled-egg

You can get stilts which sit on top of joists and raise the loft floor by about 300mm. The loft floor sits on top then. Saw them in b&q. Don't know how effective they are.

SargentDuck

Hey, I just saw these yesterday, 5 for €20!!! no bad, I'm just trying to do the maths to see which is better.