Crack the code

The construction of the BRE Innovation Park offers valuable lessons to housing providers in fulfilling the requirements of the Code for Sustainable Homes, and to the industry as a whole in improving design and sustainability. Here are 10 top tips:

Appoint a code assessor

Make sure you appoint your code assessor early and involve them in the design and specification stage. Compliance with the code requires assessments to be carried out in two phases:

• Design stage assessment: this is based on design drawings, specifications and commitments and results in an interim certificate of compliance.
• Post-construction assessment: this is based on the design stage assessment report and confirmation of compliance including site records and visual inspections and audits. A successful post-construction assessment will result in the final code certificate being issued.

For more information and contact details of licensed code assessors, visit the BREEAM website at www.breeam.org/assessors/csh.jsp
Formulate a community-wide energy strategy

An effective energy strategy that combines efficiency with renewable sourcing is critical and should be considered at a community development level rather than individual house plot level. Allow the maximum south-facing surface area possible for mounting solar

hot water and photovoltaic arrays. Specify renewables systems on the basis of standard assessment procedure (SAP) outputs rather than manufacturers’ figures (which are not admissible for the SAP assessment). To gain the full benefits of energy saving systems, ensure they have been recognised via SAP Appendix Q.

Make airtightness integral to design and construction

Airtightness has been shown to be the key issue in achieving as-designed energy performance and should be integral to the design and construction processes from day one. The design should, for example, avoid penetrations in the air barrier rather than trying to seal around them.

Proper site supervision is vital for an effective airtight barrier, so ensure the site manager is fully briefed on the importance of airtightness. When using modern methods of construction, consider the order of assembly and ensure that problem areas are made airtight before they become inaccessible. Carry out air testing of the structure as early as possible for example, at the point the building becomes weather tight, before services are installed.

If the post-completion air testing falls short of the design target it may not be possible to achieve the target with remedial works.

Keep it simple

Simple design and detailing eases the construction process and makes achieving targets more likely. A simple design also offers a number of practical advantages for example, it can allow easy access to all areas of the building envelope should any remedial work be required.

Check the quality on site

Stringent on-site quality control and monitoring procedures are essential, along with the appropriate levels of skill and workmanship. On-site management of documentation is also important for one thing it helps a project to obtain material and considerate contractor points under the code.

Get down to the detail of thermal insulation

Architects must detail every area of the building, to ensure continuity of insulation and avoid any gaps in the dwelling’s thermal envelope.

Think about overheating

Consider at the design stage the risk of overheating in summer and, if necessary, adopt a cooling strategy to design out the problem (treat this as a separate issue to that of the ventilation system). For example, include materials that will store heat and use solar shades to prevent unwanted solar gain. This can also be achieved by avoiding highly glazed designs, which makes it easier to reach the heat loss parameter at level 6 of the code. However, this must be balanced with the need for good daylighting and view of the sky.

Remember sustainable landscaping and community facilities

Sustainable landscaping and the integration of community facilities are required under the code. Credits can be earned for sustainable drainage and surface water management, bio-filtration and bio-remediation systems, and waste recycling facilities. Water management and control is also extremely important, and credits can be gained by using rainwater harvesting, greywater recycling systems and flow control valves and taps within the house.

Design for smart technologies

Design for smart infrastructure and digital communication services. The wider use of smart technologies could revolutionise the management of buildings and the delivery of community services such as healthcare and education, but retrofitting is expensive and disruptive, and is likely to result in a communications system of lower quality than that in new build or major refurbishment.

Do it now and learn from itConsumer demand for green and sustainable homes is growing rapidly and the government’s Code for Sustainable Homes has set a serious challenge for housing providers. For your projects, aim to achieve level 3 now (and 4 where appropriate) and learn from it. Those acting now to combine sustainable design and construction, with affordable cost models, will have a competitive edge in the market.

For more information on the BRE Innovation Park or to arrange a visit, call 0845 223 2966, email innovationpark@bre.co.uk or go to www.bre.co.uk/innovationpark