8
Step 4: Timber battens
Fit 25mm timber battens at maximum 400mm
centres to underneath of rafters. Fixings are to
be 50mm window screws.
4a
Batten out entire roof structure. Batten over
window opening and cut back to suit.
4b
Step 5: Rafter Insulation
From outside insert
40mm
insulation board
between rafters.
5a
Seal all gaps with
expanding foam.
5b
