"David J" wrote in message
...
Not quite diy, but does anyone have a view (positive or negative) on
modern cavity wall insulation with foam or granules.

I had a previous house done with insulation foam in the 1970s and I
had no problems at all - apart from giving myself a problem later when
trying to drop a TV cable between floors via the cavity. The foam
insulation reduced my annual heating bill by 25%, and soon paid for
itself.

At the time I remember a brief cancer scare in the newspapers about
homes treated with this foam - but that ultimately came to nothing.

I had assumed that my current house, built in 1997, would have had the
wall cavities filled with insulation slabs at the time of building -
but some recent drilling through the exterior walls confirms that I
was wrong about that. Maybe the current building regulations for
insulation were not in place in 1997.

The regs at the time it was enough to fit insulated light-weight blocks.
Not now. Worth getting done.

In the loft fit rockwool between the joists and rigid foam over the joists.
Boards on top and screws right through the two into the joists. Make sure
all cables and pipe running through the ceiling are sealed with silicon. Do
not forget the loft hatch and make it is insulated and sealed.