transfer through the insulating layer, was
essential and the Lime Green Warmshell
system, which uses wood fibre board as
the insulation layer and lime render as a
weather-proofer, was judged to fit the bill.
When insulating externally, the thicker the
insulating layer, the warmer the house will
be. The cost of fixing the insulation boards
and applying the lime render is the same
no matter how thick the boards and so the
owner chose a board thickness of 160 mm
as a suitable compromise between cost
and benefit.
For the Warmshell system at Houlston
Manor, wood-fibre insulation boards were
fixed directly to the brickwork externally
after excavating down around the sides of
the house at ground level to ensure that
there were no cold areas at the internal
floor level – a precaution taken as the
house had different floor levels internally.
The house eaves were also extended
to ensure that the roof had significant
overhang over the insulation board and
lime render.
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The wood-fibre insulation boards were
then covered by two coats of lime render
– a basecoat (with reinforcing fibreglass
mesh) and decorative finishing coat.
The benefits
Houlston Manor is now secure, warm and
weather-proof for decades to come. In the
first three months following the Warmshell
installation (October-December 2015)
the property used 2800kWh for heating,
compared to 6821 kWh in the exact same
period the previous year. This represents
an incredible 59% reduction in energy
costs! As the original brick walls dry out
and warm up over time, the owners expect
to see even greater energy cost savings.
The owner’s family have changed and
improved the aesthetic appearance of
the house – far from the first time this has
happened in its history – but, importantly,
the Manor is now ‘fit for purpose’ for the
21st century and beyond, a warm and cosy
family home that will last for many more
generations to come.