Floor Insulation

[Burnsy]

I am about to get the new carpets layed on my floors next week and have been considering whether it is worth rolling out some builders wrap/foil on the floor before it goes down. House is on stumps with 22mm particle board flooring over c section. I am putting quality underlay under the carpet and want to know whether I will gain any benefit from putting the wrap under that. Wrap is supposedly rated at 0.5 and I don't know whether this will make any decernable difference.

Cheers,
Mike

[BDM]

Hi Mike what underlay are they installing

[Burnsy]

They just refer to it as Gold underlay, it is the expensive one , nice and thick and soft to walk on.

[OBBob]

I thought the foil wrap needed a bit of an air gap to perform very well? I think if you install it before your chipbaord you are suposed to dish it between the joists? I guess every bit helps though.

[ausdesign]

Reflective foil must face on open air space to have any thermal value.

[Burnsy]

I thought that was the case, I have been thinking about it more today and wondered if I would be best finding a cheap source of styrofoam and glueing that under the floor onto the flooring.

I did once see something on ebay that was like 20 litre drums of expanding foam that was sprayed under floors. I know they use the 20 litre drums of foam in exporation drilling to seal aircore holes. This stuff is just poured down the holes and I have never heard of spraying it let alone using it to spray the underside of flooring, anyone heard of or seen this? It would be a good idea if it worked.

[ausdesign]

There used to be a similar product around in the early 80's that didn't last long because it was formaldahyde based.
Nearly all the insul. manuf. have a floor product now. It may be worth checking them out as to price.
Insulation batts between the joists makes a big difference but installation can be a real pain.