Eco-houses
Another 'staple' of the practice has been one-off private houses. Some are self-built, others self-commissioned, contractor-built.
Each has its own brief, constraints and opportunities, and we use our experience and skills to draw out from the client:
• what they really want
• what they really need
and, finally
•. what they can really afford
These were all designed to the client's brief and budget
Introduction
A 164m2 house, commissioned autumn 2005, completed summer 2007.
The initial brief was for an accessible eco-house, and was designed in line with the AECB* silver standard, which stresses the importance of highly efficient building fabric over ʻhigh techʼ add-ons. Solar hot water was incorporated, and Photo-Voltaic panels added in 2010. The result is low energy use, compared to national averages, particularly for heating:
Eco-design features
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passive solar design
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avoiding over-heating
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minimal ʻthermal bridgingʼ through the fabric
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super insulated roof
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super insulated walls
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super insulated ground floor
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high performance joinery
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high airtightness level
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mechanical ventilation
glazed south-facing lounge
canopy to bay window
by careful detailing
+ site-work
300mm insulation
250mm insulation
150mm insulation
by Nordan, Gloucester dependent on build quality central without heat recovery
Construction Details
ROOF [as designed*]
• natural slate + battens
• 350mm I-beam rafters
• 350mm insulation
• air control layer
# [*some details changed on site]
Other design features
The briefʼs excellent accessibility was guided by the ʻLifetimes homesʼ* standard. The wheelchair lift is unusual, but shows how a new house can be made 100% accessible at modest additional cost.
It also called for good natural light, and views of the existing gardens.
Materials
Conventional materials were chosen both for: client preference, historic town location, buildability by conventional builders, and the low proportion of the buildingʼs lifetime energy use comprised by the embodied energy of the materials [±10%], compared to the energy in use [± 90% ].
* see www.simon-brown.com for explanation / details
FIRST FLOOR
• ʻEco-joistsʼ to enable ducting
• central ventilation system
• conventional flooring+ plaster
WALLS
• plaster +self-coloured render
• concrete block cavity wall
• 250mm full-filled cavity
GR. FLOOR
laminate wood flooring
underfloor heating
super-insulation
concrete beam + block
conventional foundations
Lessons from the build
Overall, eco-design thinking has moved on since Ty Gwyn was designed, e.g: the welsh government adoption of Code for Sustainable Homes level 3*
and the spread of the superior, more rigorous German Passivhaus* standard.
The following lessons are shared for mutual learning:
-
procurement from committed eco-builders is vital...
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work must not proceed until overall cost is established...
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design instead to the now tried and tested Passivhaus standard...
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achieve excellent airtightness through careful site work + supervision...
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use better high performance windows next time...
Conclusions
Using ʻleading edgeʼ thinking in 2005, then compromised by contractual issues, the resulting house is a light, attractive, warm, comfortable, accessible, energy efficient + pleasant home.
Doing it again, both designer and client would, inevitably, change some things, but the house saves substantial money and CO2, with no compromise to comfort or accessibility.
To discuss any similar new-build or refurbishment project with no obligation, contact Simon Brown as below.
