The Moonstone Project: “To design and build Britain's leading ...

The Moonstone Project: “To design and build Britain’s leading autonomous Eco-house”

Before the work began
Description of the brief that was given to the builder:
To design and build an architecturally outstanding Cotswold contemporary positive energy Eco-home in harmony with its setting in an Area of Outstanding Natural Beauty (AONB).
The house is not to be connected to mains water, gas or any fossil fuels, mains foul or storm water services making it fully autonomous
Were there any special issues that had to be taken into consideration ?
The site was in an AONB area and the Planners insisted on a modern 21st Century design .
The previous owners had failed for 8 consecutive years trying to get planning permission for a property on this AONB site.
The planners insisted on a distinctive linear building cut into the hillside.
The building had to be designed to have heating only from a renewable source.
During the construction phase all building waste where practical was to be recycled on site.
A third of the building was to be underground
Who drew up the plans ?
Roderick James Architects were involved in the concept design. Centurion Western made extensive use of a 3-D modelling package called ArchiCAD to make further submissions
to the Planning Committee in order to achieve approval to build.

During the work
When was the project started ?
Design, drawings and full Planning submission with successful outcome was from July 2003 to August 2004. Project was unable to commence due to Planning restrictions until March 2005.
Construction started March 2005 and was completed in February 2009
Construction Started: March 2005
When was the project completed ?
February 2009
Were any special / unusual materials or building systems used ?
To be the best Eco house in the Country, innovative and often untried technologies had to be used in its construction.
The whole building now has levels of insulation 65% better than the very Best German Eco standard of the Passiv Haus—U values of the walls of 0.06 w/m 2 K cf. 0.15 w/m 2 K.
Full commercial quarrying equipment was brought in to excavate and process all 12,000 tonnes of Cotswold stone material on site. All this material was recycled in the battered wall construction or for hardcore for the
driveways. The only building waste removed from site was in three 8 cubic yard skips.
A Canadian ICF (Insulated Concrete Formwork) was used with water proof concrete—to provide a water proof underground basement and water proof tanking to a third of the building which was
underground.
Large Hanson 200mm and 300mm thick 7m long x 1.2m wide floor panels had to be craned into position.
Highly insulated triple glazed windows with a U value = 0.7 w/m 2 K were imported from Germany
Walls were constructed with a 1m thick Cotswold stone battered wall with a 3 degree pitch with super insulation of 400mm of extruded polystyrene to totally fill the cavities. All ground floors were built on 300mm of heavy
duty insulation
The inner wall was treated with a epoxy tanking materials and the full height of the walls dressed with a 4mm neoprene jacket to create an air and water tight structure.
Eight bore holes and a further 1 1 /2 miles of 40mm pipe was buried around the property t o provide heating to the 12Kw Ground source heat pump.
A 44 square metre arrangement of flat plate solar thermal panels provide the house with 85% of its hot water and heating requirements.
All drinking and other water requirements are met by an on site spring
Rain water is collected from the roofs and discharged via pipe work hidden in the walls and used to fill reflection and infinity pools at the extremities of the building
A two tier vertical reed bed was constructed to process all waste water on site—to drinking quality standard.
An Aquatron worm biogester unit composts all solid wastes from toilets and waste food and is then re-used as compost
The house was the first domestic property in the UK to use Rehau Earth pipes installed 3 metres below ground. Via this pipe work incoming air is ducted through 6 lengths of 50m underground Earth pipes pre-warming the
air in the winter months and cooling it in the summer months.
A full mechanical heat recovery system, filters and purifies all incoming air into the property and recovers wasted heat from the kitchen, bathrooms, tumble dryer and Aquatron bio-gester.
The house is illuminated with LED lighting saving an additional 60% over normal energy efficient lighting.
A CLIPSAL lighting and automation system was fitted into the house, with PIR’s switching lights on and off when necessary and all lighting circuits are set on timers with occupancy detection to save
further electricity. All light switches are fully programmable with SMART phone control; lights can be remotely turned on and off. The house can be monitored fully from remote internet sites.
A Schluter super thin 25mm screed underfloor heating system, provides rapid heating comparable with traditional radiators and traditional underfloor systems. The very thin Supa flow liquid screed only needs an input temperature
of 35 degrees to reach a room temperature of 21 degrees, making it perfect for the small Ground source heat pump.
Two 1500 litre stratified hot water thermal storage cylinders have multiple inputs allowing for easily connection of solar thermal, ground source heat pumps and other renewable energies.
The 3000 litre hot water storage covers the house for approximately 7 days, with any short fall being met by the Ground source heat pump.

During the work
How well were any problems and/or changes to the initial brief dealt with ? Please provide examples:
Planning Permission.
Despite a 12 month consultation period with the local Planning team, and initial 100% acceptance for our ideas, a change in personnel of the planning team, meant after 12 months they rejected our scheme.
The architect was unwilling to submit the scheme without written planning officer approval, therefore Centurion Western invested heavily in a 3D modelling architectural software providing detailed images of the
proposed property showing life like wall finishes and 3D models with DVD production showing animations of the proposed dwelling. The builder supported the customer at the planning committee meeting
contributing to final committee approval for the plans.
Over coming a very steep site;
The building site is perched on a steep hillside in the Cotswolds AONB area. Careful demolition and on-site crushing of existing industrial buildings were completed prior to the excavation 11 metres below ground into
the rock face to create the underground section of the house. The builders then had to create a wide temporary driveway down to this level for the plant including a 60tonne crane, and over 120 concrete wagons
Minimise waste and recycle, where possible, all materials on site.
We were keen that the building process should be as green as possible asking for materials and suppliers to be sourced within a 30 mile radius from site minimising the carbon foot print of the property. 12,000 tonnes
of excavated stone were re-used in the large 1 metre thick battered stone walls and the driveways and landscaping around the house. Crushing and sorting machinery was brought in to produce different sizes of
aggregates for different uses on site. Large ready mixed self coloured mortar silo’s were brought in to accurately produce a consistent mix and colour for the stone walls and minimise waste materials associated with
piles of bulk sand.
Extreme weather conditions and break-ins. 2007 Gloucester floods
The build experienced extreme flooding in the summer of 2007 —with May through to August being a complete wash out, and the nearby stream water level rising by 2 1/2 metres. November through to January was
regularly impacted by heavy snow falls. In 2005, flooding in New Orleans (USA) resulted in a 40% increase in the cost of raw zinc material for the extensive curved roof curved roof.
CWL offered costs savings in other areas to offset the unexpected increased costs. Four break-ins on site , the first within just 2 months of commencing works and resulting in over £50,000 worth of damage and theft
to machinery and equipment on site. The first theft—caused a 10 week set back as all the specification drawings and CAD models were stolen resulting in having to go back to the drawing board.
Being an innovative build.
As an experimental house using new and untested technologies with little application in the UK the builder regularly faced new challenges and worked hard to forge relationships with local and European suppliers. This
attention to detail in many areas (e.g. LED lighting system, waterproofing, triple glazing system, ceiling features, solar, heat pumps and reed beds) enabled the builder to successfully integrate a range of high tech systems
to function effectively to create a true example of a passive house. The builder was innovative in dealing with challenges and managing potential conflicts of systems on site in a timely manner. He also challenged
suppliers with potential installation issues prior to arrival on site to reduce delay and cost to the project.

Overall satisfaction
Which aspect of the work delighted you the most ?
The overall finishing—the details that most people never see. The battered Cotswold stone walling looks stunning. The 5mm shadow gaps, in the ceiling are a detail that never ceases
to make me smile. I’m delighted that all our human waste is managed on site by worms and reeds, that we create our own hot water and have rarely needed the underfloor heating on
(even in extreme temperatures of minus 13 degrees - winter 2010).
What was the most difficult aspect of the build ?
The glass box design and installation.
Huge glass windows crane and winds
Please provide examples of courtesy and considerations shown by the builder and their team during the project:
The builder was highly supportive throughout the build stepping in to support us in the initial planning stages when our architect abandoned us at the first sniff of defeat. The builder advised
us on eco products and went to great lengths to expand his own knowledge on existing products. The builder was excellent at managing site visitors whilst focusing on build aims
and timescales. He coped with extensive involvement from the client and managed our expectations and our amendments to the brief in a diplomatic but open fashion.
The builder and his team implemented a courteous builder policy.
In no more than 250 words please state why you think your builder should be “Master Builder of the Year 2010”
Centurion Western Ltd took on a hugely ambitious project —to build the best UK example of a PassivHaus. We believe they have achieved this, unlike many examples of eco houses
Moonstone is truly innovative and the eco features work in harmony with each other. There has been no need to retrofit boilers or radiators—the brief has been met.
To achieve this Centurion Western embarked on a huge learning curve with regard to innovative eco products whilst maintaining sensitivity to cost and practicalities of a family house.
They took on a lead role from planning to completion. The result is a property of 15,500 square feet of floor area (approx. the same size as 20 average 3 bedroom houses) that has a
heat loss equivalent to less than half a standard three bedroom house. Typically a normal house has a heat loss of 55 kWh/m 2 /year, a German PassivHaus has a heat loss of 15kWh/m 2 /
year and we have achieved 6.6kWh/m 2 /year.
The innovative approach to this project attracted the attention of the media with the result that Discovery TV channel has filmed the whole build process and intends to transmit 4 halfhour
programmes solely devoted to the construction of this state-of-the-art eco house.

Moonstone Room and Floor layouts
Second floor: Lounge, bar and first floor office & roof terraces
House is arranged over 7 floors—with two floors underground
Basement level: Cinema, games room and Aquatron worm biogester
First Floor: Kitchen, dining room, Grand hall, garage & Oak pod
Ground Floor: Bedrooms, library, Sauna & steam room, Swimming pool, Guest wing

Property is optimized for Passive solar gain - facing due South with large over hanging roofs for solar shading in the
summer months, while the low winter sun penetrates the glazing and heats the huge thermal mass of the house.

All glazing is triple glazed, argon filled with U=0.7w/m2k Curved zinc roofs achieve U=0.10 w/m2k Underground basement achieves U=0.07 w/m2k All Cotswold stone was quarried on site with additional stone coming from a quarry only 6 miles away.
Moonstone has an internal floor area of 1550 square metres arranged over 7 floors (the size of 20 average 3 bedroom houses), with a third of the building underground.
Total Heat loss for property is just 6.6Kw less than half a modern 3 bedroom house.

44 square metres of TiSun flat plate solar collectors, provide 3000 litres of hot water storage to two innovative stratified Proclean water tanks. From early March to mid-November 2009, all hot water came from these panels- no
additional heating was required. Other DHW heating comes from a NIBE heatpump connected to eight 70m deep boreholes and four slinky trenches with an additional 1.4Km of solar collecting pipe work.
NO FOSSIL FUELS ARE CONSUMED ON OR OFF-SITE.

Site excavations and recycling / processing of 12,000 tonnes of quarried Cotswold stone and basement floor slab

Basement construction with Quadlock walls
Ground floor beam installation

Water proof tanking to underground walls
Structural steel framework to upper floors

Triple glazed windows and curtain walling.

Curved zinc roof cladding

Stone wall cladding and insulation

Oak frame installation

Cedar cladding

Superstructure completion

Ground source heat collectors: 1.5km of slinkies & 8No. 60m deep
Underground ventilation earth pipes and insulation of underground pool and

Stone slip cladding and gabion baskets
Underfloor heating & superflow liquid screed
500m of Schluter underfloor heating pipes laid on top of a Bekotec heating system uses just a 25mm thick screed cf. a conventional
70mm screed. This results in a very responsive heating system similar to a traditional radiator system. Input water is only at 34 degrees
hence is optimised to work perfectly with a Heatpump.

Winter 2010: minus 13 degrees 18 inches of snow and still no need for heating

Landscaping & planting of wild flower meadows

The Moonstone Project