Regulations Part L and F 2010
improvement
With Parts L and F 2010 of the Building Regulations due to
be implemented next autumn, designers and developers need
to be planning now for new-build homes. Alex Hole offers a
rundown of the key improvements that will be needed
N
ext year all new houses will have to be built its larger envelope. A house with mainly south-facing
to a much higher level of energy efficiency windows will also benefit from solar gain, even in winter,
– but what does this mean in practice, and but a designer must bear in mind that too many south-
what will they look like? Parts L and F of the facing windows in a highly insulated, air-tight house can
Building Regulations are going through the first of three lead to overheating issues in the summer months.
significant step-changes en route to making all new This balance is very important. However, summer
houses carbon-neutral by 2016. overheating can be reduced by incorporating
The first stage, planned for October 2010, will see a overhanging shades to block out the high summer sun.
requirement for a 25 per cent improvement in energy Deciduous trees also act as a natural summer shading
efficiency, compared with the current Part L. Midland system, but allow sunlight through in the winter when
Energy Services has been investigating the effect this the leaves have fallen.
will have on the design and specification of new homes Following this, consideration should be given to
to meet next year’s proposed changes, and the findings the thermal envelope – and, next year, higher levels of
make interesting reading. insulation in floors, walls and roofs will be necessary.
SAP (Standard Assessment Procedure) will still Perhaps up to 400mm of roof insulation, wider and
be used to assess all new dwellings, although it is fully filled cavities and the use of the highest performing
being updated to better reflect the true performance thermal blocks will become more common. Blocks that
of the home. In practice, houses will have to increase are laid with thin joints will also help to reach the 25 per
insulation in walls, floors and roofs, incorporate higher cent efficiency improvement, as will highly insulated
performing windows, be built more air-tight and often timber framed houses. Thermal bridging could also
include renewable technologies such as solar panels or be reduced by using Accredited Construction Details
mechanical ventilation and heat recovery systems.
For some time now it has been a mandatory requirement
Alliance
It is likely that
of the Code for Sustainable Homes (CSH) to achieve a
25 per cent improvement in carbon emissions to meet
Homes
the proposed
Level 3, but next year it will be required for all new homes.
Good
changes next This does not mean that all new houses will have to be
year will require
assessed under CSH (a common misconception) – just
developers to
that Building Regulations is coming in line with Level 3
of the Energy (Ene1) part of CSH.
actually prove The starting point is to design energy efficiency into
they have
the new home by keeping the external surface area to a
reduced thermal
minimum and orientating the property so the building
benefits from passive solar gain. An ‘H’ shaped property,
bridging for example, would lose out to a square building due to New homes are due to come under the sustainability code.
48 CIBSE Journal November 2009 www.cibsejournal.com
CIBSEnov09 pp48-49 new homes.indd 48 22/10/09 17:15:31
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