Under floor boards

Well, I am just looking at various products for the job I have in mind. Any recommendations?

Arthur

You'd normally lay your hardwood boards over the pine - which will improve the insulation. It's more to prevent draughts - as warm air is heavier than cold.

Arthur2 coughed up some electrons that declared:

How about rockwool, sheepswool, celotex or kinspan between the joists under the boards? All you'll need is some small battens to support the celotex/kingspan or wire/netting (chickenwire maybe) to support the wool.

Cheers

Tim

as warm air is heavier than cold.

I disagree - warm air is lighter than cold, which is why warm air rises and draughts around your feet are cold. Basic principle of physics, I believe.

I've had celotex in mind for a loft converison some time in the future. I hadn't thought of it in terms of a floor and it seems like the easiest one to do so it looks the favourite for now.

Thanks.

Arthur

I used fibre board over joists before laying a chip floor. It both accommodated shrinkage in the (green oak) joists, and provided some sound and thermal insulation.

But for thermal if the space between the joists is accessible and usable, celotex is the best way.

Which is why, as I said, you cure draughts. Not the same thing as insulating.

This stuff looks promising for draughtproofing, mainly because it's quick to install. Whether it remains flexible for long is another matter

Not in this plane of reality. Hot air balloons would have a hard time rising if that were the case. What may be less obvious is that moist air, laden with heavy water vapour you might think, is actually lighter than dry air. That's because at a molecular level the mass of vapourised water molecules is less than that of the nitrogen and oxygen ones they replace. That means the best place for your dehumidifier is high up rather than on the floor. As it removes the water from the air the dry air sinks and fresh moist air rises to be processed by the dehumidifier. A process I'm currently exploiting by drying the results of the water leak in my kitchen with a dehumidifier upstairs.

Indeed - meant lighter. It rises. Another senior moment.