Insulation between the rafters

1. Install underlay above the rafters. For an un-ventilated roof construction, a vapour open underlay or breather membrane should be specified. For a ventilated roof structure, a traditional high resistance sarking can be used.

2. For a ventilated roof, fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces.

3. Measure the space between the rafters where the insulation will be placed and cut the insulation boards marginally wider than the space to ensure a friction fit upon installation.

4. Fit the cut Mannok Therm Roof / MR insulation boards tightly between the rafters, with the Mannok branded side facing into the building. The boards should be pushed right into the space so they are tight up against the battens.

5. To limit heat loss and prevent problems such as condensation, mould growth and staining occurring at cold spots in the construction, insulation should be continuous at junctions between the roof and other elements, particularly the eaves and gable. At eaves, wall insulation should be continued between the rafters until it butts the underside of the Mannok Therm Roof / MR boards. Where there is a cavity.

Insulation below the rafters

1. Using suitable mechanical fixings, fix Mannok Therm Laminate-Kraft / MLK boards to the underside of the rafters with the long edge running across the rafters.

2. Install timber noggins where the joints in the insulation are unsupported.

3. To form an AVCL, seal the joists between the boards. Set the boards onto a wide (30mm) bead of vapour resistant sealant applied to the under surface of all the joints and cross noggins.