1. Install the steel stud framework according to the manufacturer’s instructions

2. Cut the Mannok Therm Wall / MW insulation boards accurately to ensure they will fit tightly around openings such as window and door openings.

3. Fit the insulation boards to the external face of the steel studs, butted tightly together to ensure a continuous layer of insulation, ensuring vertical board joints coincide with a vertical steelwork member.

4. Fill any gaps between the insulation and the metal framing with expanding polyurethane foam to avoid thermal bridging issues.

5. Fix the wall insulation boards using steel channels which are screwed back to the studs. The screws must be specified carefully to ensure they can withstand the transmitted loading from the cladding, while also minimising heat loss where they penetrate the insulation. U-value calculations must take account of that additional heat loss.

6. Install an AVCL (air and vapour control layer) across the inner face of the steel studs, immediately behind the internal surface finish of the wall. This AVCL is necessary in light steel framed walls to prevent damaging interstitial condensation forming within the wall. Condensation risk analysis should be carried out to ensure the specified AVCL has a sufficiently high vapour resistance for the project. The AVCL will also help reduce air leakage into the stud cavity.

7. Depending on the depth and spacing of the studs and the U-value required of the wall, an additional layer of mineral fibre insulation can be fitted between the steel studs.