"Chris J Dixon" wrote in message
...
John Rumm wrote:

Using the PIR over the top of the joists is the best way. No titting
about cutting it to shape then!

So in cross section:

wwwwwwwwwwwwwwwwwwwwwww ---- loft boarded floor
ccccccccccccccccccccccc
ccccccccccccccccccccccc ---- PIR foam
ccccccccccccccccccccccc
##~~~~~~~~##~~~~~~~~~##
##~~~~~~~~##~~~~~~~~~## ---- joists with quilt infill.
##~~~~~~~~##~~~~~~~~~##
##~~~~~~~~##~~~~~~~~~##

Just to clarify, there has been lots of discussion elsewhere
about various methods of constructing raised floorboard support.
Are you saying simply perch them on to of the PIR foam?


You can certainly put T&G floorboards directly onto PIR when that PIR is on
a flat surface. However, I am not sure how it would perform if the PIR was
sitting on joists itself.

JW