On 31 Jan 2006 03:38:51 -0800, a particular chimpanzee named
randomly hit the keyboard and produced:

Hah, BCO is wrong...
So, I can prove it if I want. If he disagrees, he will have to show me
his calcs !

Calcs! You think the BCO hasn't got more to do than calculate the
heat loss through your roof. He'll have just looked up your spec on
the Knauf website, noted that their spec is based on 38mm wide trusses
at 600mm centres, and that yours are obviously thicker and closer, and
asked you to prove your spec.

BTW, have you allowed for ventilation? Either you need to leave a
50mm gap over the insulation, or counterbatten over. Maybe he's
assumed that the thickness of insulation will need to be reduced by
50mm.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"