347 Crescent House - Pilot Project

The building fabric is, however, aged and inefficient. The striking sapele and glass facade is central to CPB’s design idiom (and that of the latter Barbican) and rightly protected through the listing, yet is a source of huge heat loss and occupant discomfort. The single glazing alone accounts for 60% of heating losses from the homes and the original sapele window frames are badly in need of restoration. The Pilot Project at 347 Crescent House is a tester for a suite of works to be carried out across the entire block of 153 flats (tenure mix: 50% City of London tenants/50% Leaseholder) to reduce carbon emissions, improve resident comfort and alleviate tenant fuel poverty. The window frames have been subject to complete refurbishment. Rotten and damaged timber was repaired using various methods (resin repair, slicing in new timber, entire new sapele sections). New compression and brush seals were added to opening lights (coupled with other works, airtightness has been reduced to 5m3/hr/ m2@50pa) and the existing single glazing replaced with new vacuum glazing. Vacuum glazing is a relatively new technology. Two sheets of 4mm glass are bonded together with a 0.3mm vacuum created between the two sheets, creating a very thin unit (8.3mm thick) with a very high thermal performance (u-value 0.5w/m2K – better than most triple-glazing). This allows for the glass to be replaced with minimal impact on the existing frames and the appearance of the building. Important for a low-carbon future, the project will deliver a 56-59% reduction in the heating energy demand of homes at Crescent House, enabling homes to be switched to electric heating without increasing occupiers’ energy bills.