Steel Frame Details

This section shows appropriate details for light steel frame construction. With this form of construction it is important that some insulation is placed outside the steel frame to provide a thermal break and avoid condensation.

• Warm frame construction where all the insulation is outside the steel frame.
• Hybrid construction, where insulation is included both outside the steel structure and in between the steel components (a minimum of 33% of the thermal resistance should be provided outside the steel.) With this form of construction a condensation risk analysis (in accordance with BS 5250) should be provided by the system manufacturer to ensure there is no risk of interstitial condensation. An internal vapour control layer is generally required.

The details drawn in this section are based on warm frame construction but apply equally to hybrid construction.

The depth of steel frame can typically vary from 75mm to 150mm and these details are appropriate for all such variations.

Insulation thicknesses have not been shown as these depend on the thermal properties of materials. However, it is important that appropriate tightly fitting materials are chosen. Generally, a rigid insulation material is required outside the frame that acts as an insulated sheathing board. Where the hybrid construction is used, with some insulation between the frame, a vapour control layer should be provided unless careful condensation risk analysis shows that this is not necessary.

Although the drawn details shown brick cladding, they are appropriate for a range of other claddings subject to suitable detailing.

• Steel Frame Illustrations (PDF 503Kb)