introduction
Brandon Lloyd Architects Wilder Street project is a new build terrace of 9 terraced live/work units built on a tight brown field site in the centre of St Pauls in Bristol. Brandon Lloyd was very focussed on making the units as truly sustainable as possible, wanting them to achieve level 5 of the Code for Sustainable Homes (CfSH) or even level 6.
challenge
We were asked to provide an integrated service offering all the compliance requirements including Standard Assessment Procedure (SAP) and Code for Sustainable Homes. Brandon Lloyd also asked us to provide the renewable energy options appraisal and the heating system detail design. Our service was structured to provide an integrated package, by creating a small dedicated team of specialists from each discipline that followed the project through to the end.
With great foresight, the client engaged with us at the earliest opportunity and was therefore able to ensure that all areas of the Code were incorporated at the start of the project. We provided analysis and advice on many aspects of the design, ranging from the most efficient types of lighting, to the most sustainable sources for material procurement.
The greatest challenge facing the client was to ensure that all heating, hot water and lighting systems operate with zero carbon emissions (100% improvement on Part L1a of the Building Regulations). We were able to provide further assistance by carrying out a feasibility study of renewable energy technologies to provide the client with guidance as to the most cost effective and appropriate technologies to adopt.
solution
The architect specified very high insulation levels and incredibly tough air tightness targets, which were all achieved. This, coupled with high efficiency heat recovery systems, meant the heating requirement for each unit was almost negligible.
Following a process of iteration and evaluation, the final design incorporated a single communal 20kW biomass boiler with a thermal store, which provided heat to each unit via a small district heating network. The hot water to each unit was provided by a mains pressure hot water tank, with the heating provided by a heater matrix in each heat recovery unit; a heated towel rail was provided in each bathroom. To provide the final reduction in carbon emissions to achieve level 5 we recommended that solar PV systems were installed on the terrace roof.
outcome
The nine dwellings achieved Code level 5 at the designstage. The necessary carbon reduction was achieved by designing the dwelling with very high levels of insulation, corresponding to a U-value of 0.1 W/m2K for the thermal envelope. The dwellings were also designed to be highly airtight, and to incorporate heat recovery ventilation - allowing the heating requirement to be met by a single towel rail supplied by a small biomass district heating system.
"Sustain provided us with invaluable assistance on this project, without which we would have had great difficulty achieving our desired Code Level 5. At all times I had every confidence in Sustain's ability to provide the essential information we needed, regarding both the CSH assessment and the low carbon technologies specified to achieve our carbon reductions."
Brandon Lloyd, Brandon Lloyd RIBA
