Hi, We have a 1950s house which unfortunately doesn't keep the heat or sound in particularly well. We're having the carpets replaced upstairs so we're taking the opportunity to insulate the floor between the ground floor and the first floor. I've read that accessing this from beneath is best, however, because we're not replacing the plaster boards this isn't any option. We have wooden floor boards upstairs and I can remove these easily enough and work my way around. To note; there are some electrical wires and central heating pipes between floors. I was thinking of either fibre insulation like Rockwool, or board insulation like Celotex. Either of these would do the job of insulating against heat loss but I'm guessing neither would do much good against the sound problem. Does anyone have any experience of either of these? Or any other recommendations? I'd read that adding battens slightly above the plasterboard (from the ceiling underneath) would create an air gap and prevent the buildup of condensation and would also prevent the electrical wiring from getting too hot. With regards to the sound proofing. I was thinking maybe something that could be laid over the top of the joists and insulation, but underneath the wooden floor boards. Does this sound like a realistic approach? Really trying to cover all the bases with this so any advice would be greatly appreciated. Thank you.
For getting good sound insulation you need soft wood or other kinds of foam insulation. I prefer Styrofoam insulation boards as they provide good heat insulation and here Styrofoam boards are more inexpensive than other kinds of insulations. Ensure your contractors are using fire retardant Styrofoam insulation. Styrofoam boards are good sound and heat insulators. I finished flooring insulations with Styro boards as DIY.
Look at ROCKWOOL Sound Slab, available in various thicknesses. http://www.rockwool.co.uk/products/rockwool-sound-insulation-slab/ I prefer to use Knauf Earthwool Building Slab RS45 & available various thicknesses. http://www.knaufinsulation.co.uk/products/rock-mineral-wool/earthwoolr-building-slab-rs45
I worked on a project turning basically a barn into a type of cinema. Sound leakage was a big concern and it was specced to use iirc 150 mm earthwool (roll not slab). And i have to say it worked pretty well. Not total sound proofing of course but only the really low frequencies leaked and bass is pretty darn powerful stuff. This is a recommendation for earthwool
Darren Bircher needs a solution to fix both solution like 'kill two birds with one stone' . I used Styrofoam boards for flooring insulation check this item, you will get an idea about it.
Earthwool does both well, either in the slab form that Kiab linked or the roll form like this: http://www.knaufinsulation.co.uk/pr.../loft-insulation-rolls/earthwool-loft-roll-40 It's also has very good fire retardency and is a p-o-p to fit. No i don't have shares