Hello , laying insulation for wooden floor, is the aluminum side facing the concrete floor or the foam side? Cheers

no idea but I’d guessing it goes wood > foam > foil > concrete. Someone who knows what they’re talking about will be along soon enough.

My thought as well

I would guess you want the aluminium on the warm side you are trying to insulate to reflect heat before it heats up the foam. And then aluminium tape over the joins. But that is a guess.

The foil is there as a moisture barrier, so if you want to protect the foam and the flooring from moisture rising from the concrete, put it face down. If it’s a steamy wet room and you want to protect the sub floor from moisture, put it face up. It won’t do either of these things very well unless you tape the seams though.

Laying engineered wooden floor in the dining room, I just ripped out the carpet and its a concrete under…. So aluminum floor facing the concrete right? And foam side facing the wooden floor ?

The foil is there as a moisture barrier,

Foil is normally there for low emissivity. Otherwise surely you could just apply a plastic DPM film to the panels instead of foil?

If your concrete floor is anything like mine was (ie not perfectly smooth) it will put loads of little holes in the foil anyway so I would think if you are worried then put a DPM (liquid or membrane) down first?

Spotted this guide: http://www.celotex.co.uk/assets/handy-guide-2015.pdf

but didn’t see your application. When under a screed floor it goes aluminium up and the existing DPM below the concrete should protect it.

Actually, are you supposed to put that type of flooring directly onto this type of insulation? I am assuming you are using Celotex style stuff and how thick is the engineered floor? Possibly need a chipboard floor first unless it’s thick enough: https://twitter.com/celotex/status/428918487151837184

as above my first thought was foil up otherwise the concrete will puncture or damage it

also you always put the vapour control layer on the warm side of insulation, otherwise you trap moisture between the foil and insulation on the cold side

floor is fine – level and smooth actually, both next door neighbour just put the insulation then the wooden floor, but they paid someone to fit it for them and no idea which side the fitter fitted the aluminum foil side 🙁

Have just put some quick step stuff down in the kitchen.

The seams are pre taped on the foil side… So you really have to put it foil side up in order to remove the backing from the tape!