Unclealbert
New Member
Hi there, im fixing 12.5mm PB over the top of 40mm celotex on sloping ceilings. The construction is 150mm celo between rafters with 40mm celo over the underside of rafters then 12.5mm PB. The rafters are at 600 centres, question is should i have a batten set behind the horizontal PB joins or just screw them through to the vertical rafters on 600 centres and leave the horizontal joins unsupported?