1. Precisely cut the Mannok Therm Wall / MW insulation boards to fit snugly between the studs and to window framing.

2. Fit the cut insulation boards between the studs ensuring a tight fit and fill any gaps with expanding polyurethane foam.

3. Timber stud dormer checks require an appropriate vapour control layer to prevent interstitial condensation forming on the back of the sheathing. Where Mannok Therm Wall / MW insulation is fitted only between the studs, install a vapour resistant membrane, such as 500 gauge (125µm) polyethylene, across the face of the studs. Condensation risk analysis should be carried out to ensure the specified AVCL has a sufficiently high vapour resistance for the project. Laps should be sealed and the vapour control layer itself sealed to the vapour control layers in the adjoining elements and to the frame of the dormer window.

4. Where insulation boards are specified between and across the timber studs, install Mannok Therm Wall / MW or Mannok Therm Laminate-Kraft / MLK insulation boards across the inner face of the studs with the edges butted tightly together to ensure a continuous layer of insulation. If using Mannok Therm Wall / MW insulation across the studs, a vapour control barrier may be formed by taping the joints between boards with metalised tape.

5. The junction between the dormer cheek and the roof plane should be designed and constructed so as to minimise thermal bridging. This is most easily achieved where both the dormer and the roof plane have a layer of insulation drawn over the internal faces of the studs and rafters. The insulation on the dormer face can then be carried down the face of the supporting rafter to meet the insulation to the underside of the rafter.