Recent developments include a change to Approved Document B, which brought in stricter fire safety standards. Changes to Approved Document L also introduced a brand new requirement to test each home for air tightness. Additionally, installers are now required to submit photographic evidence showing that insulation has been installed correctly as part of the Building Regulations England Part L (BREL) report.
All of this demonstrates a need for architects to consider both the design and installation phases seriously – the more straightforward and foolproof a product or system is, the less likely there will be errors on the final build.
Specifying products that are both high-performing and easy to install is not easy – especially for applications that may not even exist. Insulation experts Knauf Insulation recently highlighted this issue by researching common installation challenges on real-world construction sites.
Real-world research into installation challenges
To help close the gap between the specification stage and real-world performance following installation, Knauf Insulation visited construction sites and spoke to contractors to identify their challenges.
One of the main issues was around the installation of cavity barriers, which are used to seal the gap between the insulation and the masonry facade, creating compartments to stop flames from spreading. Cavity barriers are required by building regulations, but workers on site reported that the available installation methods compromised the performance of the barrier.
Typically, to install the cavity barrier, bricklayers must first cut recesses to the width and height of the sheathing insulation after it has been installed.
They then attach the fixings to the sheathing board before finally inserting the cavity barrier. It’s a laborious, time-consuming process that can potentially have wider implications on performance.
When viewing the finished installation, it was clear that ‘breaking’ the sheathing insulation to insert the cavity barriers could result in unintentional air gaps, which could compromise the thermal, fire safety and acoustic performance of the system.
Knowing this, Knauf Insulation began developing a cavity barrier that could address these issues.
An industry first
Knauf Insulation has produced the Rocksilk® RainScreen FFCB, which is fixed directly to the insulation, to prevent the need for bricklayers to cut the sheathing insulation following installation.
This patented non-combustible solution is part of a system that comprises Rocksilk® RainScreen Slab sheathing insulation for behind masonry façades and the fixings. The system has been certified to provide fire resistance for up to 90 minutes of insulation and integrity (EI90) in the residual cavities of buildings with masonry façades – three times the requirement of the building regulations.
It has been tested for use with steel frames, timber frames, masonry and concrete substrates and can be used for both high and low-rise constructions, so it is suitable for a broad range of projects. The substantial brackets typically used to secure cavity barriers have also been replaced with slimline ‘pegs’ to reduce thermal bridging. The cavity barrier is installed as the brickwork is built, and fixings are installed from the outer leaf rather than to the inner leaf.
Architects need only choose between three width and depth variations, which accommodate all sizes of cavities. This makes product selection simple compared to competing ranges that feature 70+ options.
For architects looking to specify safety from the design stage and minimise the risk of issues arising from installation, choose the Rocksilk® RainScreen FFCB for a quick, easy cavity barrier solution.
