Ashwood House is a development of Manhattan-style apartments in the desirable Surrey commuter town, Camberley. Situated in a converted 1960s office block, developer Berkeley Homes Southern Ltd needed to ensure the 116 luxury flats were as energy efficient as possible.

This was a particular concern for the properties situated above the first floor car park, which has open walls to allow adequate ventilation of exhaust fumes. As a result, the specification stipulated a U-value of 0.25 W/m²K.

Chris Body, Business Development Director at RPN Ltd, the specialist sub-contractor at Ashwood House said: “We approached several insulation manufacturers to discuss the different options available. Knauf Insulation’s Rocksilk^® Soffit Linerboard Standard met the brief in terms of thermal and fire performance. It can be used on uneven substrates and looks fantastic – all of which were key priorities for Berkeley Homes.”

Aesthetic appeal

How the insulation looked was an important part of the brief as Berkeley Homes wanted a solution that would be aesthetically pleasing. Rocksilk^®Soffit Linerboard Standard features a black glass veil facing, so no additional finishing was required. This meant that RPN Ltd has been able to install the slabs perpendicular to the ring beam to create a quilted effect across the ceiling.

A high-performance solution

The other specification factors were thermal performance and fire safety. Knauf Insulation’s Technical Support Team undertook U-value calculations to determine that 130mm Rocksilk^®Soffit Linerboard Standard would be required. It is manufactured from Rock Mineral Wool, has a thermal conductivity of just 0.034 W/mK and is designed to insulate structural soffits in applications such as open sided car parks.

It is non-combustible with the best possible Euroclass A1 reaction to fire classification, so will not contribute to the development or spread of a fire should it occur. Rocksilk^®Soffit Linerboard Standard also has excellent sound absorption characteristics so will help to ensure that residents are not disturbed by the noise of cars parking beneath their flats.

Better for installers

The insulation was supplied by distributors CCF Ltd who delivered it to the site in line with the schedule of works. It was then installed by RPN’s specialist team.

Rocksilk^®Soffit Linerboard Standard is easier to install correctly than other insulants. The product recipe makes each slab rigid, which ensures the insulation maintains continuous contact with the substrate, preventing gaps that can reduce thermal, fire and acoustic performance.

Rocksilk^®Soffit Linerboard Standard is manufactured with ECOSE^® Technology, Knauf Insulation’s unique bio-based binder that contains no added formaldehyde or phenol. It is made from natural raw materials that are rapidly renewable, and is less energy-intensive to manufacture than traditional binders, so it is more environmentally friendly.

Products made with ECOSE^® Technology are soft to touch and easy to handle. They generate low levels of dust and VOCs, and have been awarded the Eurofins Gold Certificate for Indoor Air Comfort. This means they are kinder to the installers who use them too.

A safe solution

Ultimately, using Knauf Insulation’s Rocksilk^®Soffit Linerboard Standard means the Ashwood House car park ceiling not only looks aesthetically pleasing, but it helps to meet the increasing demand for non-combustible insulation in car parks too.