An external wall in an extension I'm building is specified as 0.34U value,
made up as follows:-
Externally rendered 100mm dense concrete blockwork.
80mm cavity part-filled with 40mm Kingspan TW50.
Inner leaf 100mm thermalite block.
Drylined internally with 9.5mm plasterboard and skim.

As this is a kitchen / diner extension, I'm keen to tile directly on to the
thermalite and leave out the drylining in order to make it easier to fix
kitchen cabinets etc.
What will be the thermal effect of leaving out the drylining, and by how
much will the U value be changed.Will the building inspector be interested?
BTW the extension was started prior to April 6 2006.
Regards
Donwill