"The Natural Philosopher" wrote in message
...
Alex wrote:

fred wrote in message ...

In article , Alex
writes

The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex

If you are rebuilding the inner leaf, I would suggest celotex (or
Kingspan)
as it is available in a range of thicknesses and is regarded here as the
best
insulation material, much better than polystyrene or others. I believe
that
the claims of foiled bubblewrap brigade are to say the least optimistic.


OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...

Reflective properties of foil have no bearing on heatloss: Its there as
a vapour barrier only.

Not according to tests. See Actis. Do a Google a uni in Florida did tests
that were very positive.

When using it, use the proper al foil tape to seal each bit to studs.

25mm celotex is not very much - about equivalent to 50mm rockwool.
Its just about allowable in combiantion with twin brick. Not as good as
one would prefer,. but a lot better than nothing at all.

Sealing up airgaps is CRUCIAL in windy weather.

Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?

I'd say that is a fine idea.

Thermal blocks with Celotex in the cavity.