Are Alumasc’s insulations non-combustible?

Posted by Ashlea Williamson

Q1. What is the fire rating of Alumasc Extruded Polystyrene?

Fire performance is declared Euroclass E under EN 13501-1. A flame retardant additive is also present that makes it capable to resist, for a short period of time, a small flame attack without substantial flame spread.

When ballasted with either 20/40mm grade aggregate (minimum depth of 50 mm) or fully-supported cast stone or mineral slabs of at least 40mm thickness, the roof may be considered to be of designation AA (low vulnerability in Scotland) and so is unrestricted by the national Building Regulations.

Q2. Are there any non-combustible insulations compatible with Alumasc roofing systems?

Two insulations rated separately as ‘non-combustible’ (i.e. class A1 to EN13501) are Foamglas and Rockwool Multi-Fix Dual Density Mineral Wool. Both products are compatible and available as a system within the Alumasc product offer as part of a warm roof assembly.


For further information about Alumasc’s insulations contact our technical team on 03335 771 500

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