The message
from Roger contains these words:

New timbers on top of the insulation? Or on top of the original joists
with the insulation between the new timbers?

Right angles to the old timbers. I had to split the new insulation to
make space for them but in most cases it conicided (not surprisingly!)
with an existing split.

--
Skipweasel
Pay no attention to that man behind the curtain.