Hi , I live in a 60s bungalow and need to replace the chipboard floor in the lounge, obviously it’s a good chance to insulate, the joist are probably 6×2 with another foot or so of void below, what thickness insulation should I use? What type? Celotex, normal loft insulation? Wall slabs? Do I need a gap between the chipboard and insulation? Thanks all

I used a breathable wool type held up with a breathable fabric stapled to the joists. Made a massive difference. No problems with damp 10 years later

10 or 150mm Cellotex is normal i think. Youll need to put some form of support to hold it up under the floor boards, be that battens along the lengths of the joists, or across like noggins, i dont think it matters.

Ours is tight to the underside of the floor.

I might look at finding some form of simple cheap L bracket that you can fit with a staple gun, that would be nice and easy.

Or a 6mm batten on each side, with a staplegun that will do 15mm

or just cut it tight enough that it wont budge on its own?

Given that the amount of heat lost through the floor is significantly less than the ceiling/walls I’d be fitting normal loft insulation.

[if you’re doing this from above – which you should if you value your sanity] Staple plastic mesh to the sides of the joists to create a cradle and then put the insulation on top.

Way cheaper and quicker than celotex.