"Tim Lamb" wrote in message
...

Insulation between joists below under floor heating.

Having promised no wall hung radiators I am now stuck with getting the job
done! Ground floor no real problems: grooved insulated sheet to take the
pipes covered with standard chipboard or screed for the new bit.

Upstairs life gets expensive and difficult. All the suppliers call for
insulation below and in contact with the heated floor. In a chalet
bungalow, there is no such thing as a standard floor joist spacing. The
dormer cheeks are double or triple timbered and the intervening space
filled with ladder work on joist hangers. Elsewhere walls have double
supporting timbers.

I have been considering cross battens but this adds a huge cost and the
suggested sizes (30mm x 70mm) are not found off the shelf and particularly
not untreated.

Pre-grooved chipboard is an alternative and cheaper solution. Both systems
call for insulation between the joists and in contact with the underside of
the floor. PIR foam is not cheap, needs careful cutting/fitting together
with supporting battens. Rockwool is cheaper and easy to cut and fit
but... how do you stop it ending up resting on the ceiling plaster board,
light fittings and electrical wiring?

Chicken wire netting? Some sort of cross batten or?? My floor joists are 9"
deep and Rockwool 6". Perhaps lengths of plain galvanised fencing wire
stapled between the joists? Any impact on wi-fi transmission?




When we did up the house and holiday cottages, I bought rolls of garden type
green nylon netting off ebay, and stapled it to the joists, laying
insulation batts suspended by it.

Andrew