Residents in a Bristol social housing high-rise tower block are benefitting from warmer and more attractive homes, thanks to a combination of two tried and tested External Wall Insulation (EWI) systems from Alumasc.
Owned by Bristol City Council, Northfield House is an 18-storey block of 99 flats, surrounded by a complex of three lower-rise blocks totalling 60 flats. As part of a programme of improvements for all of the tower blocks in the city, the council instigated the £3.5m refurbishment of the blocks to address problems such as poor thermal performance, condensation, mould growth, water ingress, structural movement and crumbling concrete. These had been caused in part, by the original methods and materials used to construct the buildings which included reinforced concrete frames, concrete flat slab roofs and cavity brickwork.
As a specialist in the provision of EWI solutions for high rise buildings, Alumasc was able to offer a combination of two EWI systems to improve energy efficiency at Northfield House. This met the need to use a system with high impact resistance at ground floor level, which wasn’t a necessity on the higher floors. Alumasc’s Swisslab EWI system was ideal and was installed with a traditional, clay brick slip finish. On the remaining 17 floors, Swistherm EWI finished with acrylic brick slips was more suitable, being a lightweight solution which minimises the structural impact of the system.
Both systems are BBA approved, fully warranted and are available with a range of design and specification options, across many building types.
CHALLENGES AND AIMS
Other than the obvious requirement to improve thermal performance, another important challenge of the scheme was to colour-match the brick slips with the existing brick finish. Lee Carter, South-West area manager for Alumasc, explains:
“To meet the requirements of the planning permission, we had to ensure that the new materials were a perfect match to the original exterior of the building in terms of colour. This meant matching the clay brick slips to the original substrate, and then matching the acrylic brick slips to the clay ones. The completed facade meets the planning conditions fully, with all material colours successfully matched.”
Over 4,000m2 of Alumasc external wall insulation was applied to Northfield House over a 10-month period by Alumasc registered installer Rateavon Ltd. As a result, U-values were reduced to 0.29W/(m2k) from 1.75W/(m2k) signifying greatly improved energy efficiency.
Commenting on the finished project, Danielle Mills, assistant quantity surveyor at Rateavon Ltd, said:
“The improved thermal performance of these blocks has reduced carbon emissions and heat loss. Residents’ living conditions have improved and their heating bills are now significantly lower. The blocks have retained their original appearance and problems such as damp, condensation and water ingress have been eradicated, reducing future maintenance costs.”