Which comes first...

[mjfreespirit]

Chicken or the egg...

No, but seriously, should I lay vapor barrier first THEN frame out floor put in insulation then plywood OR frame out floor, put in insulation, THEN put down vapor barrier then plywood?

[Robin97396]

This is what I've been told during building code classes. I'm sure there are varying opinions.

In housing construction the vapor barior is put nearest to the outside. If a vapor barrier is put on the inside, the warmth tends to make condensation on the vapor barior surface.

[Stu & Filo. T]

Originally Posted by mjfreespirit

Chicken or the egg...

No, but seriously, should I lay vapor barrier first THEN frame out floor put in insulation then plywood OR frame out floor, put in insulation, THEN put down vapor barrier then plywood?

I have plywood floor & this is what I did

Treated floor with 3 coats Red Guard.

Lay down vapor barrier, extend it up side 6in.

Layed down 2in styrofoam insulation.

1 1/8 in T&G subfloor

I talked it over with a contractor friend of mine & that's what he recommended .

[Robin97396]

That's the same method. Vapor barrier goes on the cold side.

[ghodges]

Originally Posted by mjfreespirit

Chicken or the egg...

No, but seriously, should I lay vapor barrier first THEN frame out floor put in insulation then plywood OR frame out floor, put in insulation, THEN put down vapor barrier then plywood?

Absolutely, always put the vapor barrier to the outside. You def don't want to have condensation forming in your subfloor!

Sent from my MotoG3 using Tapatalk