Ten years after completion - a 2024 update

Ten years after completion a number of further imovements have been made to the house and surrounding land.  Here is a summary:

1. Heating: The large wood-fired boiler has been removed together with the large thermal store; both were purchased by other eco-enthusiasts. The heating is now generated by a Mitsubishi 11.2kW Ecodan heat pump couple to a 300L Solar Thermal Cylinder. The 'Melcloud' software controlling this is very easy to use and operates the units with almost no user input. The efficiency and heat generation is now so efficient that half of the solar thermal tubes had to be removed to avoid overheating in summer. These too went to an offgrid eco development near Oxford.

2.Energy use: To optimise the use of the PV generated energy from the barn roof, a Tesla Powerwall 2 battery has now been installed. Illogically installing this alone would have incurred VAT but installing at the same time as solar panels would be VAT free. We therefore added a further six 410W solar panels ( an additional capacity of around 2.5kW and enabling the installation to be VAT free. Over the last couple of months UK government have removed this requirement an batteries can now be added to existing solar VAT free. The excellent Tesla software controlling charging times enables the battery to be programmed to recharge at off-peak rates (just over 7p per kw from Inteilligent Octopus Go).

3. Testing v2h - bidirectional charging: Colemans Hill Farm is now a partner in a test programme for v2H - using the considerable spare capacity of an electric car to power the house (our Nissan Leaf has a 60kW battery and for quite a lot of the time is standing idle). This is also pretty automatic so the EV is programme to top up the battery during off-peak and if remained plugged in, will automatically take over supplying the house when the Powerwall is exhausted. Using the combination of the Powerwall and the Nissan battery enables the house to be heated with off-peak electricity on most days for a full 24hrs.

4. Growing vegetables:  two reclaimed greenhouses and a number of raised beds made from pallets, enables quite a lot of vegetables to be grown organically

5. Biodiversity:  Some of the original oak trees along the drive are now more than 10 metres high and a large area behind the house has been sown with native wildflower. The original pond has been enlarged (with a rubber liner) and this has attracted frogs, toads and newts together with mallards which have bred on site. Some control is required to dissaude a large Grey heron from using the pond as a free larder! Maturing hedges, wildflowers and more uncut grassland have increased the numbers of mice and voles which in turn has attracted nesting barn owls to the next boxes installed in the barn. In 2022 a pair produced 6 eggs but didn't seem to know what to do with them. In 2023 a different pair produced a late clutch of 4 eggs from which two youngsters survived to maturity. A new larger box has been put up in 2024 and we haope that one of these nesting pairs will be back in the Spring.

Three and a half years later - would we do this again?

Yes - three and a half years have passed, and the house has matured (and so have we!).
Were we to do this again, then quite a lot of things would be done differently. So some reflections ...

Too much emphasis in the design on appearance and it was left to us to research and implement all the environmental features - extremely efficient insulation, triple glazing, a passivehaus foundation and more, local labour, and as far as possible local sourced materials. It looks attractive but has more than 20 corners making it more expensive to build and much more difficult to make airtight.

The extra cost of including green energy and water technology was worthwhile - though today some of this would have been done differently. Taking advantage of government incentives to encourage the take up of renewable energy has been controversial and not well managed by government. Doubters said we would never recoup the money (£28,000 or so) spent to put 9.8kW of solar PV on the barn in 2011. In fact it paid for itself in 7 years and will almost certainly continue to produce an average of 9500 kW hrs of clean energy every year for at least another 25 years - probably more. More than 70,000 kW generated so far; less than 50,000 used with the rest exported to the grid. Now you could install the same 9.8kW for well under half the cost and in many cases would be cost effective without any subsidy. During the first year - a rather a cold one - the house needed what we regarded as an excessive amount of electricity from the grid.

The solar water heating provides virtually 'free' hot water for more than 6 months and valuable base-heating of the 800l thermal store for the rest of the year. Though widely regarded as one of the most efficient and effective solar installations - mainly in passive houses - it was failed by the nuclear expert the government sent in to inspect it and it took him well over an hour to find out how it worked. Why did it fail? Because some of the heat it generated from the sun was contributing to heating the house; it should only have been used to produce hot water. So the government grant withdrawn in favour of supporting less efficient installations.

Some final thoughts and tributes

The oak around the house is beginning to mellow and the surrounding landscape is slowly maturing. The grass - all sown from seed - is also improving, though thistles and docks are also doing well! We've planted another 15 trees - a mix of oak, ash and alder and sown wild flowers around the completed pond which is already attracting some gorgeous dragonflies and the occasional heron. The two rustic seats in the foreground were made from the old cypress taken down at the start of the build.  Our bird count is now in the low 20s with heron, barn owl, little owl (resident), sparrowhawk and woodpecker taking pride of place. Several insect 'hotels' are being well-used but are also supplying food for the woodpecker. 

The house is proving to be negative energy (no - the one announced yesterday on the BBC was not the first!). Last week the PV panels celebrated their 4th birthday and showed 39,170 kW on the meter - and have generated more each year (10,313 this year). We have used just under 26,000kW since we moved on site indicating a surplus of 13,000 kW which has gone back to the grid. From an economic standpoint the installation has already paid back well over half the initial cost in just four years. The potential for storing 'spare' solar generated electricity is developing fast and this is a technology we are watching with interest.

The solar thermal system is working well and provides all the hot water we need for around 7 months of the year and very useful base heat all-year round.  Even in mid winter the water in the thermal store rarely drops below 25 degrees C. Unfortunately the powers that be have decided that our system does not qualify for the Renewable Heat Incentive as some of the heat generated by the evacuated tubes helps to heat the house - not just the domestic hot water. Large thermal stores (ours is 800 litres) are widely recognised as the most efficient way of optimising solar heat but the regulations say that they must only contribute to hot water - not space heating. So if you are planning a new build, think carefully about using a thermal store. It may be the most efficient system, but OFGEM doesn't recognise this and you won't get any RHI payments.

Reclaiming the VAT was a time consuming process putting all the receipts in chronological order and making a matching spreadshett to meet VAT specifications. There are never enough hours in the day during the build but doing the VAT monthly as the build progressed would have made it much less arduous at the end. In my view HM Customs were prompt and fair despite what others have said.  

Our old VW Golf worked hard moving goods around during the build (still running on 100% biofuel) but we decided that at 15 yrs old it might prove expensive at the next MOT, so decided it was time to change using the VAT refund. We had been watching the development of the electric car market for some time and after much thought, decided that a plug-in hybrid would best suit our requirements. We found a demonstration Prius plug-in at an attractive price with only 1300 miles on the clock and have now run this for nearly a year. Technically it only does 16 miles on a charge and it would be nice if it did more like the Audio, VW and Mitsubishi which have arrived since.  However in practice I think it was a sensible choice. Most of the time we charge it for free from spare solar (charging time is just over an hour and a half) and on dark winter days, we charge at night on off-peak. We rarely get less than 80 mpg equivalent - even on long journeys - and the speedo is currently showing the last 750 miles at 142 mpg.

Winner - Best Sustainable Dwelling 2015

One pleasant surprise was to learn that our Building Control Inspector had recommended the house for a special award. On 17 April we were invited to an Awards lunch in Stratford and Colemans Hill Farm was announced as the winner of the best new sustainable dwelling 2015 - a fitting tribute to three years of very long days and some sleepless nights!

It is also a fitting tribute to all those who contributed to the build - some of whom went way beyond the usual service you would expect from contractors. 

A big thank you to:

Winchcombe Reclamation

who carefully removed the old farmhouse

Pete Tonks
for designing the new one

Jay Hubbard and Robin Vincent of English Brothers
for supplying the timber frame & their constant support

Phil of Eazylay Concrete at Admington

who delivered and poured seemingly endless cement, often out of hours

Jason Watts and the Forest of Dean 'hemcreters'

who installed the hemcrete under monsoon conditions

who installed the PV and solar thermal

Martin and Stuart Turville

who laid the bricks

Ben of JBM Scaffoldingfor erecting the scaffolding at short notice

Built Environment Technology
who installed the MVHR system

Elliot Atkinson and his friendly team from Black Pig

who glazed more than 50 fixed windows

Frank Horsfall of Calarel Ltd
who made the triple glazed oak doors and windows

John Devine
who painted them

Bernard Prickett Joinery

who made the oak staircases

Clint Parker
for the electrics

Solar-Sense UK
for the PV and solar heating system

Mario the Plumber

who meticulously laid the kitchen floor and bathroom tiles

Chris Hurley

who helped with the foundations and installed the wood stove

Martin Bennett, Head of Stratford District Council Building Control

for constantly monitoring the build and his helpful advice

Charlie and his team from Cotswold Green Energy

for the UFH, the plumbing and the EcoAngus boiler
and their marvellous support throughout the build

Steve and Debbie Savery (& son)

for their patience, impeccable carpentry and painting skills

Peter Boait of Exergy Devices

who generously designed and installed
the intelligent energy management system

and above all

Nigel Brookes

who after selling us his mobile home, ended up as our constant mentor
for his skills preparing the foundations, installing the passive slab

the complex drainage system, the rainwater harvesting, making the pond

and landscaping the entire site.

We could not have completed this build without him.

markandsonia@gmail.com  01386 438572  07776 036884

Mark Boulton  July 2015

Complete - well almost!

View from East side over wild pond - August 5 2014

After a further three months or so of seemingly endless "final" tasks we have (virtually) finished though more seeding and planting still remains to be done.

 

Following is a summary of the final aspects of the build.

With just two of us working a couple of days a week progress has been slow.  Because the land is on three levels a full length block wall needed to be constructed the full length of the house with associated drainage and then faced with bricks - many from the original farmhouse. 

Once this was complete the patio was built with steps to the upper garden and into the rear entrance and sun room.

This just left finishing the pond in the lower garden which appears to be holding water (the overflow rainwater from the underground tank together with the run off from the house) without the need for a lining. 

Sections from the foundations from the original farmhouse were used to make a path and some natural stone (thank you freecycle!) used for edging. A range of native aquatic plants and two toads and two frogs discovered under the Cotswold stone.

The last pile of topsoil saved when digging the foundations was used to landscape the area leading down to the pond which is now being planted with trees and shrubs.

Milestones

What was the final timeline?

February 2011 - Moved into old mobile home on site; preliminary site surveys take place boundaries established and fenced; designer working on plans

April/May 2011 - Pre-planning application presentation completed and submitted mid-May; preliminary drainage and levelling of site.  Solar PV installed on barn roof; veg plot fenced and recycled greenhouse erected

June 2011 - temporary wind turbine superceded by establishing grid connection - an interesting (and frustrating) experience over some months!

July/September 2011 - Planners slow to respond to application but after some intervention, eventually grant planning permission with 13 conditions 28 September

October/December 2011 - work on site to meet planning conditions including construction of bat loft in barn, selection of bricks & tiles, and levelling of site
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January 2012 - Conditions fulfilled and sent to SDC; demolition of old farmhouse and continued levelling of site

March/April 2012 - Footings dig to support brick walls; perimeter walls constructed and central core filled with old bricks ready for building passive slab. 

May 2012 - Structural polystyrene (ESP) arrives but turns out to be the wrong material; replacement material arrives within four days with Air Packs in Ireland pulling out all the stops. What an incredible service! Slab complete day before timber frame arrives 28 May

June 2012 - Wettest "summer" for years. Timber frame erected under challenging conditions

July 2012 - Hemcreters arrive from Forest of Dean to mix and pour hemcrete under continuing torrential rain

August/September 2012 - Outer (non-structural) brick walls started at the same time as tiling commences; first of the large oak trusses moved into place. Crane arrives at end of month for the two very large oak window frames. Sun room frames also require crane to move into position.  Oak porch uses man!

October 2012 - Cotswold Green Energy begin first fix plumbing; triple glazed windows arrive. Extensive reticel foam insulation through roof

December 2012 - Underfloor heating system laid out.  Solar thermal evacuated tubes installed with Sigma tank for heating. Electricians begin first fix and MHVR team compete mechanical heat ventilation system.  Small "Badger" Wood stove fitted and plasterers begin work
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January 2013 - Second fix electrics, plastering, plumbing and painting

March 2013 - Steve finishes oak staircases and carpets fitted upstairs;

May 2013 - Biopure septic tank installed and Nigel begins excavation for Stormsaver rainwater harvesting system

June/September 2013 - Finally moved in June whilst work continues and mobile home sold to young couple starting new build in Solihull

October 2013 - Lots more finishing work internally and landscaping/drainage externally.
Pair garage doors constructed from spare oak floorboards.  Bespoke Wattbox energy management system installed with energy used remotely monitored from Cheltenham 

November 2013 - Magnet ex-display kitchen and Everhot cooker installed
_____________________________________________________________________________

May/June 2014 - House finally officially signed off after completing air test; work continues on walling at rear and construction of patio

August 2014 - Work on the pond finally completed and formal date of completion 4 August 2014

It can't be six months

It doesn't seem possible we have not updated the blog for more than 6 months.  Just when you think you are almost finished there are still seemingly endless small (and not so small) tasks to be completed.  A bannister for the back stairs, tidying up hairline cracks which form as the timber frame settles, the last sections of oak cladding, doors for the workshop and the garage, a wood shed and a very long retaining wall on the south side. Add to this relocating the enormous heap of clay, spreading the topsoil and seeding the lawn areas and the last blog in May seems like yesterday.

Preparing the lower lawn area for seeding

But looking back we have made good progress. The house is 99% complete and the major landscaping done.  Now the rain has returned the pond and the wildlife area in the lower garden will probably have to wait until the spring.

Finishing the oak cladding on the rear of the garage

The following "point and shoot" photos will give some idea of the interior.  When time permits they will be updated with more professional images.

It can't possibly be six months

It scarcely seems possible that six months have passed since we last updated the blog. Yet for the whole of that period (apart from a 4 day break in September) we have continued to work every day on the build. Just when you think you are nearly there, you realise there is a still multitude of finishing touches still to do; many of them turn out to be significant tasks in their own right once you actually start to tackle them.

Preparing the lower garden area for seeding

The house itself is now 99% complete and the landscaping well underway - though I suspect it will be next Spring before we start the pond and the wildlife garden.  What follows are a series of "point and shoot images" just to give some idea of how the house looks inside. These will be replaced by more more professional images when we have more time.

Garage doors made from oak floor boards and spare timber left over from the build

Entrance hall with central staircase

Open plan living areas

Kitchen and adjacent sun room

Landing and ensuite

Studio room over garage

More to follow in due course

Too busy to blog!

Despite the silence we have been extremely busy - too busy to blog - so herewith an attempt to catch up.  With better weather and longer days we have been able to concentrate on installation of the septic and rainwater harvesting tanks, both of which involved a lot more digging and shifting soil.

After careful research we chose the BioPure 2 septic tank system from "We Build It Ltd" in Bridgnorth.  The tank is UK made (and reasonably local), has a 25 year guarantee, is low maintenance, consumes only just over 40w. The tank only needs emptying every 3-5 years  and the technical support is excellent.

The rainwater harvesting system is from Stormsaver - a company with a long experience of commercial installations which has more recently begun marketing domestic systems. We chose the German manufactured 5000 litre low profile Monsoon tank which has meant less digging backed up by their Eco Control system and the highly efficient 90w submersible pump.  

The company claims a high level of customer care and support and we think this is an under statement!  Over the last few days they have responded immediately to a host of our email queries, sent us the new colour installation manual updated just a couple of weeks ago and suggested we fit a couple of updated parts in the tank (they have a policy of continuing research and improvement) which they have sent out free of charge. The company is also active in raising money for charity and has donated more than £13,000 to WaterAid in the past couple of years.  Couldn't be a better choice!

The current spell of dry weather has enabled us to begin shifting the mountain of soil and to spread some of the top soil which was carefully saved during the original excavation of the site. With luck we should be able to able to connect the downpipes from the barn and begin excavation of the pond in the next couple of weeks. 

Peter from Exergy Devices has also been constantly tweaking his bespoke intelligent Energy Management System (controllable from his office in Cheltenham!) and this is now settling down and provides us with a daily supply of hot water above 50 degrees - all of it free over the last week when the tank has on occasion reached more than 65 degrees C.

More on this in the next blog.