"Dave Rowell" wrote in message
...

We're having a loft conversion done - work starts tomorrow - and I'm
wondering about upgrading the roof insulation they've specified. They use
TriIso9 as standard,

Get them to put "only" high perfroming cellotex in all around. Triso9 is a
con.

The Advertising Standards Authority got them claiming their reflective
insulation is 'Equivalent to 200mm of traditional thick insulation'. A
complaint has been upheld after ASA went to independent technical experts.

The judgement can be seen at:
http://tinyurl.com/s6c2p

DO NOT let them put this stuff in.

and it could be upgraded by adding 50mm of cellotex
between the rafters . This would reduce the
U-value of the roof from 0.25 to
0.15 according to the engineer.
Cost of the upgrade would be £630 - ouch!

Tell them to reassess without the Tiso9 and all cellotex.

Can anyone hazard an educated
guess as to what the likely pay-back time will
be?

Go for the most you can get. Fuel keep on rising in price. Payback is
quick.