Insulation above the rafters

1.  Install a timber stop batten across the rafters as shown in position C above, with the batten equalling the thickness of the Mannok Therm Roof / MR insulation.

2. Lay Mannok Therm Roof / MR insulation boards above the rafters, butted tightly against the stop batten and supported on both sides by the rafters. If required, cut the insulation boards to ensure they fit tightly and secure temporarily with appropriate nails.

3. Install the vapour open underlay over the layer of insulation. The underlay should be vapour open (vapour resistance <0.25MNs/g) but water resistant, to protect against wind-driven rain and snow.

4. Install counter battens over the vapour open underlay along the layer insulation, with each counter batten in line with the position of the rafters beneath. The counter battens should be nailed to the stop batten previously installed.

5. Using the calculated fixing requirements specific to your design, install the fixings along the counter batten at maximum 400mm intervals.

Insulation between the rafters

1. 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.

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

3. Install battens along the side of the rafters to support the roof insulation boards.

4. 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. Tightly fit the insulation to the ridge plate and carry over and tightly butt the wall plate at eaves.

5. On the internal side of the roof, fit a vapour control layer the insulation and the internal finish.

6. Finally, install the internal finish, such as plasterboard.