Alumasc’s Swisslab External Wall Insulation (EWI) system has been used at Boxtree Lane, an outstanding new residential development from Origin Housing.

Affordable housing provider Origin were looking for exceptional levels of thermal efficiency and a high quality, low maintenance finish for the exemplar project which comprises 14 flats in Harrow Weald. With the EWI and render system so critical to the success of the project, the installer ALD Group, specified 1400m2 of the industry-proven Swisslab system with 160mm phenolic insulation and a silicone render finish in white and basalt grey. ALD were confident that the phenolic foam insulation would achieve the target U value and the silicone render would meet the brief for an attractive, robust and low maintenance solution.

YOOP architects’ used passive design principles on the project which embed energy efficiency performance within the structure itself, through higher levels of insulation and air tightness compared to normal build methods. The building material was a single skin of recycled concrete block, externally insulated with the render finish which, with the internal plaster used, resulted in air tightness. This Passivhaus approach aimed to ensure the building envelope would be as heat retentive as possible.

Swisslab is an insulated render system that provides outstanding energy efficiency. Insulation materials are mechanically fixed direct to a continuous substrate and faced with a choice of traditional and lightweight renders. As a direct result of the Swisslab system, a U-value of 0.12W/m2k has been achieved, creating comfortable all-year round living conditions for residents with minimal use of heating.

Boxtree Lane has been Shortlisted for Best Small Development in the UK Housing Awards 2013. The development has also become a model for Zero Carbon homes for Origin Housing and has achieved Code for Sustainable Homes level 3 at a very affordable cost due to the Fabric First Approach, which the EWI system helped to make possible.