insulating living room ready for underfloor heating

[lidster]

Hi all,
just bought 1930's semi detached. I want to put underfloor heating in the front room (16sqm) under laminate flooring. the room needs completely stripping first. Old gas fire out, existing radiator out, wallpaper stripping and re-skimming walls. As I am doing all this I would like to insulate it best I can to get the best efficiency from the underfloor heating. the floor is suspended floorboard over joists. not moving in till next month but had a few questions.

1.Is it worth lifting the floorboards, putting 75mm thermal PIR boards between joists? this would be in addition to using the 10mm thermal boards I will be getting that go on top of the existing floorboards, then heating element, then laminate flooring? or is this all overkill if using the thermal boards on top of the existing floorboards...

2. Which way does the foil face on the thermal PIR boards, upwards toward the original floorboards or downwards facing toward the ground? This alway confuses me - is the foil just to stop moisture - not reflect heat?

3. Can you get PIR boards that go in the ceiling? If you can I assume this would trap the heat in the room better. Again - is the extra work/cost worth it in terms of heat eficiency in the room?

4. One of the walls is the party wall with the semi next door. I am wanting to put Soundblock Plasterboard (the blue colour!) across this wall. Should I just dab to the existing wall, or strip back to brick - batten it with more insulation in between? Im looking for better sound blocking properties with this wall rather than insulation, but would hope I would benefit from both.

5. was looking at Green Glue. some american sound block adhesive (looks dear!). Anyone used it and can recommend? http://www.greengluecompany.com/. Time wise it would be easier than doing 4. above.

thanks for any help/ replies

 

[Deluks]

Worth doing. The foil is on both sides so it can go either way. Loft roll would be much cheaper between the floor joists, suspended on chicken wire or garden netting.

Better to make sure the loft is well insulated and leave the ceiling. After all, any escaped heat will serve to heat the rooms above.

Soundblock on green glue would work to reduce sound transmission. As would battens with rockwool in between, or plasterboard onto resilient bar. The latter must be correctly installed!

 

[lidster]

thanks for replying deluks.
Green glue certainly looks easier but I have just priced up and it is very expensive. about £140 to do 10sqm. add to that soundbloc boards....... anyone used greenglue on a party wall that can comment on how good it is?

cheers