Ventilation
- Breather membrane: Ensure a minimum air gap of 25mm between insulation and breather membrane (vapour resistance less than <0.25MN/s/g).
- Felted Roof: ensure a minimum air gap of 50 mm between insulation and felt (ventilation from eaves to ridge according to British standards
Pull insulation taut, fix to rafters with staples (galvanised min. 14mm).
Overlap insulation from 50 to 100mm at each joint and staple every 50mm on the rafter.
Tape all joints with ACTIS ISODESIF tape to give an air tight finish.
Fold finishing edges under minimum 50mm, and staple every 50mm or trap with final batten

Over rafter application

Roll insulation horizontally, starting along the bottom of the roof
Batten horizontally between rafters, allowing joint to be stapled and taped:
- Staple every 50mm (galvanised 14mm staples).
- Overlap joints 50-100mm.
- Cover joints with 100mm ACTIS ISODHESIF tape.
Fix vertical battens ensuring a minimum gap of 25mm between the insulation and the membrane.
Fix breathable membrane following manufactures instructions.

Under rafter application

Unroll the insulation, starting along the top of the roof.
Batten horizontally between rafters, allowing joint to be stapled and taped:
- Staple every 50mm (galvanised 14mm staples).
- Overlap joints 50-100mm.
- Cover joints with 100mm ACTIS ISODHESIF tape.
At the bottom of the roof pitch, staple the insulation directly onto the timber wall plate.
Battens (25x35mm min.) should be fixed in line using appropriate nails, ensuring that there is always a minimum air gap of 25mm between the insulation and the plasterboard

The installation information and diagrams above are taken from the ACTIS Product and application guide (PZ182). For more detailed information, please refer to this document.