On Mon, 14 Apr 2008 17:39:33 GMT someone who may be Fred
wrote this:-

I'm not sure whether the house (built mid-70s) has cavity wall
insulation or not; how can I tell?

They should check this first.

If I do need it, is £140 a good price and are some companies better to
use than others?

The first thing to check is whether you can get it free or cheaply
http://www.energysavingtrust.org.uk/what_can_i_do_today/energy_saving_grants_and_offers
is a good starting point to check on this.

Whether £140 is a good deal or not partly depends on the number of
exterior walls your house has and its height.

I understand they inject something into the cavity but what do they
use? Is it like that awful expanding foam that you can't clean off?

No. They usually use small cut fibres which are blown in.

What stops it rising up the wall and coming out of the top

Gravity. A little will probably escape from the top, but can be put
back in for neatness.

or through air bricks etc?

They should check that all openings are sleeved before starting.

We have a meter box cut in the side of the wall. Is there a danger
that the meter box will be flooded with foam?

None at all if it is installed properly. Does it have gaping holes
in the back?

Also the builders for some unknown reason decided to put the soil pipe
and rising main in the cavity behind the bathroom wall. I don't know
if I am worrying unnecessarily but if we ever needed to access the
soil pipe or main, would it be possible if they were caked in foam?

The fibres can be moved to access things, though neither of those
things should be in the cavity wall.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54