Non-combustible insulation for flat roof projects
meets Approved Document B guidelines

Introducing a new insulation for inverted flat roof scenarios offering the highest level of protection from fire available on the market. BauderGLAS Inverted Insulation is the ideal solution for projects that are exposed or incorporate hard landscaping and is most suited to balconies and terraces requiring non-combustibility and regular foot traffic.

New Requirement of Approved Document B – External Walls and 'Specified Attachment'

In 2018 Approved Document B (AD B) was amended to incorporate Requirement B4 Regulation 7 — the Government requirement to ban combustible materials as part of the external wall in buildings containing dwellings or institutions. Regulation 7 also introduced a new term 'Specified Attachment' which was included in the ban of combustible materials along with other parts of an external wall. The definition includes a balcony 'attached' to an external wall. For areas established correctly as balconies on “Relevant Buildings”, Regulation 7(2) states that non-combustible materials should be used.

Bauder Technical Director - Nigel Blacklock comments “As the recently published BS 8579 makes clear for the purpose of fire, a balcony is not over a habited/conditioned space and therefore would not normally be insulated, but if it is insulated for cold bridge mitigation or part of the balcony is over a conditioned space then the insulation must have a suitable compressive strength and be non-combustible.”

Roof Insulation Fire Performance

The fire performance of individual construction products, including insulation as a separate component, is covered within BS EN 13501-1. Within a Bauder warm roof waterproofing system for TS 1187 test 4 the insulation, be it mineral wool, cellular glass, or PIR, is not directly exposed and is therefore determined by the performance of the cap sheet and its system classification of BROOF(t4); thus these insulants in-situ all conform to Building Regulations for External Fire on Roofs in the same way - not one achieving a higher rating than the other.

The exception is for a balcony (if a “Specified Attachment” on a “Relevant Building”), where if insulated it will need to be non-combustible and have a suitable compressive strength for this application. Balconies, whether warm or inverted are usually fully covered with hard landscaping and are therefore often deemed to meet Building Regulations without testing (Classified Without Further Testing as defined in European Commission Directive 2000/553/EC).

Generally, materials manufactured in whole or in part from plastics will achieve an ‘E’ rating, making non-combustible ‘A’ rated insulants, such as BauderGLAS, which is manufactured from cellular glass, a more suitable material to include in a balcony specification because of its excellent fire performance. This non-combustibility meets the recent amendments to Approved Document B regarding ‘Specified Attachments’ on “Relevant Buildings”.

BauderGLAS Insulation

Non-combustible BauderGLAS Insulation is available in flatboard and tapered variants for warm roof situations, and as a special inverted grade with a pre-applied inorganic coating, all of which achieve a Euroclass A1 rating – the best result attainable. BauderGLAS Insulation has been specifically designed for use within roof situations on concrete, metal, plywood, OSB, or timber decks and there are suitable grades that can be used in conjunction with all of Bauder’s waterproofing systems to meet the required U-value.

BauderGLAS is suited to roofs, balconies, and terrace applications, with its high compressive strength able to withstand heavy foot traffic and can be used in areas requiring a non-combustible insulation option. Inverted roof systems are favoured in concrete structures; however, it is becoming increasingly challenging to specify a system that satisfies the non-combustibility requirements of AD B for "specified attachments” on Relevant Buildings. The Euroclass A1 rating achieved by BauderGLAS Inverted Insulation not only meets these obligations, but also satisfies where necessary both the client and insurers requirements for new build and refurbishment projects.

Manufactured from more than 60% recycled glass, BauderGLAS Insulation is totally inorganic, contains no flame-resistant binders and is without VOC or other harmful substances.

When specifying an insulated waterproofing system for roofs, balconies, or terraces, BauderGLAS offers non-combustibility and a high-compressive strength, giving the building owner peace of mind.
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