Code for sustainable homes: case studies volume 2 - Gov.uk

For simplicity, this case study focuses on
the construction and technical specifications
(including sustainability features) for the Code
Level 3 and 6 units. However, the sections on
scheme implementation and lessons learnt
include information on all five units. The
technical specifications for all the units
are available on the Miller Homes website:
www.millerhomes.co.uk/millerzero/
CONSTRUCTION AND
BUILD SYSTEM
Despite the near identical appearance of the
units, different construction and build systems
were used on all the units. This included thin
joint masonry for the Code Level 3 and 4 homes,
structural insulted panels (SIPs) on the Code
Level 5 home and storey height aircrete panels
for the Code Level 6 home. The specific
construction and build systems for the Code
Level 3 and Code Level 6 homes are described
in more detail below:
Code Level 6: The new build unit has been
constructed using storey height aircrete panels
and 200mm of external wall insulation. The
internal walls have been finished using wet
plaster to improve airtightness. The whole unit
has been externally rendered and in some
places cedar cladding has been used.
The floors were constructed 300mm thick
aircrete pre-cast flooring system with 110mm
thick urethane insulation and a screed finish.
The unit has underfloor heating with the
pipework laid in the screed finish. The first floor
also has under floor heating within joist void.
The mono- pitched roof was constructed using
timber joists, with 280mm rigid urethane
insulation with low emissivity foil insulation laid
in three layers, as well an insulating plasterboard
layer to the internal side of the roof construction.
Biomass boiler supplying the Code Level 5
and 6 homes
Code Level 3: The new build unit has been
constructed using thin joint masonry walls
containing a 90mm cavity which has been
injected with glass mineral wool insulation,
with the internal walls finished using standard
plasterboard on dabs. The whole unit has been
externally rendered and in some places cedar
cladding has been used.
The floors were constructed using beam
and block pre-cast floor system, covered by a
100mm thick polystyrene insulating board with
a screed finish. The mono-pitched roof was
constructed using timber joists, with 160mm
rigid urethane insulation with low emissivity
foil laid in two layers in order to achieve the
required U-value.
36 | CODE FOR SUSTAINABLE HOMES | CASE STUDY 8