Building envelope specialist CA Group has incorporated Knauf Insulation’s Earthwool® glass mineral wool insulation into its innovative curved roofing solution for Prologis and BMW, at the car manufacturer’s 43,600m2 distribution facility in Northampton. The aesthetically pleasing design offers a curved profile without the significant price tag normally associated with this type of structure.

Sustainability was high on the list of priorities for Prologis and BMW and this is reflected in the design of the roof, which was created using CA Group's Twin-Therm® technology, a fully-walkable cost effective solution that provides a high degree of flexibility and exceptional air tightness levels.

The choice of insulation used on the project was critical. CA Group selected Knauf Insulation’s Earthwool® glass mineral wool for its excellent environmental credentials, acoustic properties and thermal performance. The combined result is an efficient, highly sustainable distribution centre, which has been rated Excellent by BREEAM.

Earthwool is manufactured with the revolutionary ECOSE® Technology, which uses a formaldehyde-free binder that is free from phenols, acrylics and blowing agents; with no artificial colours, bleach or dyes added.

Furthermore, ECOSE Technology is up to 70% less energy intensive than traditional binders, delivering superior environmental sustainability - as well as producing a ‘super-soft’ and easier to handle wool, with a natural brown colour. Earthwool products are also non-combustible, which mitigates fire risk and limits the spread of fire, as well as the spread of toxic and damaging smoke.

Brian Watson, Group Development Director at CA Group commented: “Choosing to incorporate a product that we know has been sustainably produced – using high levels of recycled material and an innovative binding technology – means we can continue to demonstrate our own commitment to sustainability. Not only this, it helps us to maintain our high standards of construction quality and thermal efficiency.”

Other sustainability measures include the reduction of wasted space in the roof cavity, thanks to the curved design, and the introduction of eaves to eaves roof lights, which make the most of natural daylight, minimising shadows and reducing the need for artificial lighting.

Watson continued: “Roofing innovations don’t come more exciting than this. The benefits of curved roofs have long been recognised but, in the past, the associated price tag has prevented widespread adoption of the solution. We have used modern technology to reduce cost while delivering all the benefits one would expect from an innovative design solution.

“Incorporating Knauf Insulation’s glass mineral wool insulation into our system has certainly helped make this possible. It’s easy to handle and install, as it adapts to and follows the curvature of the roof, with no air gaps. On the roof this has helped us achieve a U-value of 0.23, together with a sound Reduction Index (SRI) of 42 db-Rw, and on the walls the U-value is 0.35 with an SRI of 39 db-Rw, which is a great result.”