| CASE
STUDY |
Denby Dale
Passivhaus |
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“We wanted to build a PassivHaus using
British construction techniques, with, as far as possible,
materials you could find in any local builder’s yard."
Bill Butcher, Project
Leader
- First UK Passivhaus to be built with
cavity wall construction.
- One of the first certified Passivhaus
homes in the UK
- Minimal heating - using 90% less
energy for space heating than the UK average
- £141K basic build costs for a 118m2
three-bed detached house
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LOCATION |
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West
Yorkshire |
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PRODUCTS USED |
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CLIENT |
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Green Building Company / Green Building
Store |
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MAJOR CONTRACTOR |
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Bill
Butcher - Green Building Company |
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KI PROJECT MANAGER |
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Matthew
Prowse |
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COMPLETION DATE |
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February
2010 |
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CHALLENGE
An ambitious project, and one of the first certified PassivHaus
homes in the UK - the Denby Dale PassivHaus in West Yorkshire, had
to to use 90% less energy for space heating than the average UK
dwelling – with a space heating need of only 15 kWh/m2/ year. The
three bedroom property is the first UK Passivhaus to be built in a
traditional style using cavity wall construction and had to be
built to a tight budget of £141,000.
SOLUTION
“We decided to go down the cavity wall path and arrived at the
design for several reasons including: planning restrictions,
thermal store, cost, and maybe most important of all,
buildability,” explains Bill Butcher, Project Leader.
Excellent performing insulation is obviously fundamental to
Passivhaus construction and the Denby Dale house has 300mm
Earthwool DriTherm 32 Ultimate cavity slabs in the walls, 500mm
Earthwool® CarbonZero Loft Roll 44 in the roof void (both of which
incorporate ECOSE® Technology) along with 225mm of high-performing
Polyfoam® Floorboard Standard insulation in the floor.
“We’re fully filling the cavity with glass mineral wool
insulation for the walls above ground, because it helps minimise
air movement in the cavity and offers greater flexibility, fitting
snugly around the ties, openings and imperfections of the masonry
surface.” comments Bill Butcher.
Economics, performance, availability, ease of fitting and
reducing thermal bypass were all among the benefits of the Knauf
Insulation products chosen.
BENEFITS
Glass mineral wool was specified over rigid insulation to ensure
a tight thermal fit. Earthwool DriTherm Cavity Slabs are flexible
enough to eliminate air gaps and prevent heat loss due to their
inherent ability to knit together at joints between the slabs. If
rigid insulation is used and fitted badly with too many gaps, air
movement around and between the insulation boards is increased,
which can drastically reduce its insulation value.
Earthwool DriTherm Cavity Slabs are BBA Certified for all
exposure zones and formally guaranteed for 50 years to prevent the
transmission of liquid water from the outer masonry leaf to the
inner masonry leaf.
In addition to its thermal performance glass mineral wool also
has other sustainable features. In manufacture it uses a high
content of recycled glass bottles and requires less overall energy
consumption than some alternative products, resulting in less
carbon emissions. In addition, it can be recycled at the end of a
building’s life and has zero GWP and zero ODP. ECOSE Technology
further extends these established green credentials as it is
manufactured with 70% less energy than traditional binders and the
products contain no dyes or added formaldehyde – providing the
ideal solution to the eco-friendly house.
Images courtesy of Green Building Store
