What is the floor area of your project in sq ft or sq m? Do you have any floorplans you can provide?
Could you tell us any interesting facts or remarkable features about your project?
Our aim was to achieve energy neutral (in that we generate more energy than we use) and water neutral (in that we capture more water than we use) and keep waste to a minimum.
Fabric First – The whole building is wrapped with Rockwool dual-density external wall insulation. We have a double skin brick wall in the original building which is retained (so it acts as a thermal store) and which has cavity wall insulation and then outside that we have 110mm of Rockwool which is rendered with Baumit acrylic render. A similar level of insulation is under the floor with Hexatherm XChip and under the roof with 300mm glass fibre; the external shell is constructed as airtight as possible with Proctor Procheck Membranes throughout. All windows and doors are triple glazed.
Solar PVs – We have 26 Viridian in-roof solar panels – on SE and SW orientations so can generate a maximum of 6.75kW (which needed separate application to the grid – we just got in with the last tariff incentive so we receive FIT Payments). Since connection, we have generated an average of 25 KWh per day with a max of 40KWh per day and a minimum of 2kWh in a day. This is very similar to our projected generation estimates. We therefore planned for sufficient solar energy to power an electric car which we are in the process of purchasing, and in future we plan for a house battery. We have good records of our solar production and energy use; we have generated over 4.9 mega watt hours to date.
Heating/Hot water – We have an IBoost system which supplies all of our hot water from the PVs (we have retained the existing gas boiler but since the IBoost was installed we have only used the gas to boost hot water on one day). For space heating we have Thermaskirt Radiators, one section of skirting in each room, however the house is so well insulated that it held at 19 to 20 degrees C up to mid-October before any gas heating was needed. There are electric towel rails in each of the three bathrooms with timers and thermostats. We have the back up of a woodburning stove (which has direct air supply to preserve the air tightness and enable the MVHR to function correctly) and we have retained all the wood from the building works (an amazing amount of offcuts even on a relatively small build like ours) so that will fuel us for several years.
Ventilation – Titon MVHR (Mechanical Ventilation and Heat Recovery) with 120mm ducts serving every room – all the wet rooms and kitchen are extract points: all the bedrooms and living rooms have air supply points (in the kitchen we also have a recirculating extractor hood above the hob.) So the MVHR runs continuously – said to be 92% efficient in transferring the heat from the exhaust to the intake supply – though how you test that, I don’t know. MVHR can be boosted if necessary.
Waste, Embodied Energy and Recycling – We have been very mindful of material recycling. We elected to renovate and remodel rather than to demolish and rebuild, partly because the house we had purchased was, according to our structural engineer, structurally very sound and partly because to demolish would produce a great deal of demolition materials which could not be reused. The penalty for this decision is that we have paid VAT on all renovations which seems grossly unfair as well as costly. Even having made this decision we were very surprised at the amount of demolition materials and also waste associated with any building works. We were therefore determined to reuse or recycle all we could. We retained all the top soil from around the building which contributed to very substantial raised beds in the vegetable garden; we did muck-away any subsoil but all hardcore from demolition of garage, chimney and internal walls we retained and broke up to form the subbase for the drive; all timber we retained for reuse or the wood burner; all metals we took to the local National Metal Recycling NMR site 4 miles away: copper; lead; aluminium; cables; ferrous metals for which we received a total of £764; all cardboard/paper/painted timber (unsuitable for the wood burner) we took to the local recycling centre to get it into the correct streams. Therefore, we did not have any skips, apart from one small plasterboard skip, as plasterboard is not something that you can take to the recycling centre.
We purchased some second hand materials – most notably all the wood floors. We found it difficult to source any wood floors with reasonable environmental credentials as most solid hardwood flooring appears to come from France or much further afield: engineered wood floors have a mixed provenance and involve the use of various unpleasant glues. So we sought second hand and found a superb Canadian Maple floor from a Sports Centre only 5 miles away which was being demolished to make way for new housing. It took time to repair some of the tongue and groove before we could lay this, and then hours of sanding and treatment with ‘Junker’s’ lacquer – but we think it was worth it as we got enough to cover the whole of the downstairs. Serendipity had it that this floor was the very floor that we learned to dance on some 30 years ago – a nice story and emotional attachment for us. For the upstairs rooms we found a reclaimed engineered oak wood floor, without such a nice story, which we sanded off and treated with linseed oil – oil which was actually grown by a friend of ours, and the same oil we used to treat all the internal doors. For bathroom, shower and utility room floors we opted for marmoleum, a modern form of linoleum which is more environment friendly than vinyl because it also utilises linseed oil. Fortunately, we like the smell of linseed, and this natural oil is also a constituent of the rust red paint which gives the timber cladding of the extension its distinctive look. This is a Swedish paint called Falu Red which has been used very effectively in Sweden for several hundred years – anyone who has been to Sweden will recognise the unmistakable colour which finishes nearly every house in the Swedish countryside – its main constituents are a crushed biproduct of the Swedish copper mines mixed with linseed oil. We have also used environmentally friendly paints by ‘Earthborn’ throughout the interior.
We have a 3000-litre rainwater harvesting tank and all the downspouts from the slate roof run to a common sediment trap then to a filter and into the tank. The pump in the tank is triggered by a ‘rainwater harvesting’ unit which pumps on demand to a header tank which serves the three WCs and the washing machine. In addition, we have an outside rainwater tap which comes direct off the rainwater tank. We are keen gardeners and grow most of our own vegetables and water, in this very dry part of the world, is critical for successful growing (we are about 22 inches of rain per year in Manningtree – one of the driest parts of the country).
We have been involved in wildlife conservation most of our working lives, so we are incorporating wildlife features into our home where this is possible e.g. bat bricks, swift boxes, bat boxes.
In conclusion, we have tried hard to meet environmental credentials throughout. We have not succeeded in all areas and we are not going for Passivhaus or Enerphit status because there is a significant cost in registering for these standards. However, we have done our very best to reduce our carbon footprint at considerable expense both in terms of money and particularly time in sourcing the materials as best we can. We did have to compromise in many areas, for example, we would have preferred second hand Welsh slates for the roof but our experienced roofer advised against it partly because of wastage and partly cost, so we ended up with Spanish slates but at least they are from Europe rather than South America or China.
Experience at the Centre
How many times have you visited The National Self Build and Renovation Centre before?
How the Project Management Course helped us
I (John) came on the course run at the time by Mike Hardwick.
I already had some experience of running building projects through my work where I was involved in building several Visitor Centres - 11 different Centres, to be precise.
I therefore knew that my Project Management of our own project had to be tight - I chose to go on the NSBRC’s course to sharpen up my approach to Project Management and, even though I had significant experience, I found the course a very useful overview which reminded me of lots of things and raised several issues that I had not previously considered.
Having looked back on my notes, I would pick out the following as particularly helpful:
- It was useful that I went on the Project Management Course about the time we got planning permission, so we knew we were going to build but we had not gone through the process of selecting contractors.
- The course made me very conscious of the Mantra - ‘Cost, Quality and Time’ - many occasions we would research to get the Quality that we wanted, then have to compromise on Cost or not be able to get exactly what we wanted because the contractors were going to be ready for materials and we could not get what we wanted on Time - so again would need to compromise.
- The course meant we were not afraid to put our money where it mattered - external coverings; windows and doors; good quality slates; good flooring and stairs.
How the Heating your Home Course helped us
Caroline attended the Heating your Home course run by NSBRC Technical Expert David Hilton.
It was a very useful overview of all the options available for heating, ventilation and energy efficiency, including those that would be required in a very low energy refurbishment such as ours.
I was very ‘green’, in the inexperienced sense, about all these matters, at the same time as wanting to be as ‘green’ as possible, in the environmental sense. Attending this course during the early planning stage of our project helped us to consider and research all the available technologies and come to what we believe is the right solution for us.
We also met an expert at the NSBRC to discuss heating, and he demonstrated the concept of the micro-ASHP for water heating. We decided not to go for this as it seemed to conflict with the principles of operation of the MVHR – because it would divert warm air away from the heat exchanger.
What did you enjoy most about your visit to the NSBRC?
Talking to the Experts and the Exhibitors.
Would you recommend the NSBRC to a friend, and if so, what aspects of the Centre would you recommend?
We have recommended The National Self Build and Renovation Centre to several people contemplating a similar build to ours. We also took our Architect to NSBRC. We are at the point now where people want to come and see what we have done at our place – just as we went to see other Self Builders before we embarked on our Project.