Changing Specifications for Non-Combustible Insulation and Cladding

In response to heightened focus on the insulation and cladding used in developments, many of our clients have changed Phenolic and PIR insulation to non-combustible insulation, and metal cladding to non-metal alternatives.

This trend is being observed even on buildings less than 18m tall due to increased caution on insulation and cladding.

Changing the insulation product has a number of design implications including:

• 0.05-0.10W/m²K higher U-values (higher heat loss) or 30-60mm thicker walls (insulation) to meet the design U-values;
• Interstitial Condensation Risk would have to be checked as the properties of the insulation vary;
• Thermal Bridge details would need to be re-assessed.
• Sustainability requirements are still met (i.e. supplier is accredited to  ISO14000);
• Re-designed fixings for cladding and revised documents and drawings (i.e. structural);
• Re-submitting material examples for planning approval.