"Geoff Pearson" wrote in message ...


"Geoff Pearson" wrote in message
...
I am thinking of improving the floor insulation of my house. Under the
ground floor of my 1897 stone-built house in Edinburgh I have a space
about 1.6m high under all the rooms so access for work is very good. My
energy bills (gas+electricity) are about £2800 a year.

The floor is a standard Edinburgh floor: 11 inch joists with the space
between filled with ash and covered in plaster, supported on riven wooden
strips, themselves supported on battens along the joists. This deafening
(as it is called here) is about 3-4" thick. The floor is standard 1 1/8
inch tongued and grooved boards. The space below the riven timber strips
to the lower edge of the joists is about 6".

So there is space to add insulation below the deafening and access is
easy.

First question: is it worth doing? With deafening in place that provides
quite a thick layer - but then in more modern houses cavity walls do get
insulated so maybe the deafening is not a good thermal insulator
(although good for sound). Insulation is cheap enough and it is bound to
reduce my costs - more importantly it might make the place warmer.

Second question: how to do it? I can put mineral wool rolls in the space
and hold it in place with netting. Or should it be slabs of something?
Do I need vapour barrier - I think not?



Just to finish the story: The Energy Savings Trust arranged for Carillion
to do the work, paid for by Edinburgh Council/Scottish Government, for no
cost to me in April. All complete in two hours - now I have to work out if
it makes a difference.

When we did our house re-furb we insulated the suspended ground floor by
loosely stretching nylon mesh (*) across the joists, and placing cavity wall
insulation batts between the joists supported by the mesh. Mesh was stapled
to stop it moving, then we laid the flooring on top. Worked very well and
kept a ventilated space below.

(* the sort used for fruit cages)

AWEM