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

TECHNICAL
PERFORMANCE
External Fabric
300mm cavity wall consisting of an external
brickwork skin, 100m cavity fully filled with
100mm mineral wool insulation and an internal
skin of 100mm ultra lightweight aggregate
blocks, finished using standard plasterboard
on dabs. U-value of 0.28W/m 2 K
Roof
Pitched timber truss, concrete interlocking
tiles, 400mm mineral wool insulation laid
in two layers with the first of 200mm laid
between ceiling joists with second layer
of 200mm laid at 90 degrees to first over
ceiling joists. U-value of 0.17W/m 2 K
Floor
100mm concrete slab over a layer of
120mm urethane insulation. U-value
of 0.15W/m 2 K
Doors and Windows
SCHEME
IMPLEMENTATION
The design of the completed units is typical
of newer homes in the surrounding area,
with only the photovoltaic cells installed on
some of the rented units presenting any
less-than-usual external features on the
development. The low energy merits of the
housing were considered a very desirable
attribute for this development, and the
photovoltaic cells were installed to address
fuel poverty issues.
The developer was keen to demonstrate
that achieving Code Level 3 did not require
significant changes to its standard housing
types. Minimal changes to the super structure
of the building were required and primarily
achieved through higher levels of insulation
in the roof and the inclusion of a heat recovery
exhaust air heating and hot water system.
Training was provided by the supplier of the
heat recovery exhaust air heating and hot
water system for local plumbers in order
to effectively install the system.
The development during construction
Double glazed uPVC windows and doors.
U-value of 1.8W/m 2 K
Air-permeability
The target was 7m 3 /h@50pa which was
achieved by all units during the final air
permeability tests, with a small number
of units achieving improvements on this.
CASE STUDY 5 | CODE FOR SUSTAINABLE HOMES | 13