Low U-Value Building
When it comes to saving energy, Sainsbury’s supermarket stores pay great attention to the efficiency of both the in-store display cabinets and the total building envelope. Specifically, when it came to adding a new first-floor extension to its store in Brentwood, Sainsbury's chose a building method which minimised disruption to the normal operation of the existing store.
The new floor would accommodate a customer cafe, a lobby area for a new elevated car park, customer toilets and baby-changing area, staff facilities and a bulk storage area for general merchandise. This £1.4M modular scheme consists of composite building panels manufactured by the Portakabin Group. The key to the success of the project lies in the use of the off-site building solution, which on this project reduced the programme time by four weeks compared to a traditional site-based construction method. The extension was constructed from 42 steel-framed modules. These were manufactured off-site in York and pre-fitted with internal partitions, sanitary-ware, flooring, kitchen equipment, glazing, plumbing, electrics and brick cladding, before being delivered to site. In addition to the reduced building time, the off-site construction method ensured that modules were constructed to the very highest standards, taking advantage of modern factory manufacturing procedures. The modules were installed in just six days, minimising disruption to supermarket customers.
The foam insulation, which forms an integral part of the panel structure, was produced from a two-part chemical system supplied by IFS Chemicals. The Portakabin composite panel product, the insulation for which has been fully tested to EN 13165, and has gained approval by the BBA, exhibits substantial strength, is relatively lightweight, and shows high thermal efficiency. The foam provides an initial thermal conductivity of 0.021 W/mK and a declared value of 0.024W/mK. This ensures U-values which significantly improve upon the current Building Regulations.