Non-combustible inverted roof insulation, myth or fact?
The post-Grenfell Tragedy amendments to Building Regulations Approved Documents B (ADB) introduced ‘Specified Attachments’ within Regulation 7 for the first time, clarifying them as balconies, solar panels and sun shading. Under the requirements of Regulation 7, ‘Specified Attachments’ must be constructed using products that achieve a European Class A2-s1,d0 or Class A1 when tested to BS EN 13501-1 to be acceptable for use in ‘Relevant Buildings’*. The only exception to this is the waterproofing membrane, which is covered under Regulation 7 (3) (g) membranes.
With all inverted roof insulation boards achieving a European Class E or lower, the only solution until now has been to switch to a warm roof construction using either Cellular Glass or Mineral Wool insulation. But this leaves the waterproofing immediately beneath the balcony surface at risk of damage during the installation of the surface finish and, subject to the finish, at risk of damage in use.
To assist waterproofing manufacturers and contractors in overcoming these potential issues, Quantum Insulation have been working with insulation partners FOAMGLAS® to develop a Non-Combustible Inverted Roof Insulation Board. The outcome of this activity being the development of a new product called FOAMGLAS® INVATHERM™, the World’s first Non-Combustible Inverted Roof Insulation Board, facilitating inverted roof balcony construction for the first time.
Typically installed as a two-layer system INVATHERM™ consists of a base board and an upper board, with the upper board having a unique high density facing. Once installed, FOAMGLAS® INVATHERM™ is covered with a Water Flow Reducing Layer (WFRL) in the same way as any other inverted roof insulation prior to the surface finish being fitted. When installing the WFRL the recently issued LRWA Guidance Note No.14 Best Practice for the Installation of Water Flow Reducing Layers in Inverted Roofs should be followed.
To support customers, QI and FOAMGLAS® are providing installer training to help ensure applications meet the fire performance requirements of ADB Regulation 7.
With Regulation 7 currently under review by MHCLG, Quantum Insulation will continue using this QI@QI column to assist roofing contractors and manufacturers to navigate the changes in construction regulations.
* Relevant Building are high-rise buildings that contains flats, as well as hospitals, residential care premises and student accommodation above 18 metres in England and Wales and over 11 metres in Scotland.