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John & Caroline Hall

John & Caroline Hall's finished renovation / extension project

John and Caroline undertook a complete remodelling and extension of their home, aiming to achieve an energy and water neutral eco-home.  

Floor Plans

What is the floor area of your project in sq ft or sq m? Do you have any floorplans you can provide?


John and Caroline - elevations.JPG

John and Caroline - floorplans.JPG

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).

Other Points

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?

Five times.

What would you say is the most helpful feature or resource at the NSBRC?

The chance for quick meetings with experts at the National Self Build & Renovation Shows, the opportunities to see different products on display and the choice of various courses. John attended the one-day Project Management course and Caroline attended the one-day Heating your Home course.

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.


John and Caroline’s Renovation and Extension Journey

What first inspired you to undertake your project – what did you hope to achieve?

John worked in the Environment sector all his life, latterly in conservation as CEO of Essex Wildlife Trust. We became increasingly concerned about Climate Change and Global Heating and the impact that this was having on the conservation of habitats, species and the future of the planet. When we retired, it was time to stop talking about it and do – we reviewed much in our lifestyle and set out to reduce our footprint particularly in terms of energy and water use. We hoped to achieve a comfortable long-term home which would be energy neutral and water neutral (in that we aimed to capture more energy and more water than we used) and we wanted to minimise any building waste.


What was the cost of the land?

The existing house and land cost £320,000.


How did you find the land? Do you have any tips for others currently searching for a plot?

Our initial aim was to find a plot for a new-build eco-house. We wanted a plot which was large enough for growing all our own vegetables. John had grown vegetables for the table since he was a boy and wanted to continue partly for environmental reasons, and partly for the pleasure of growing good food. We despaired at Mangetout peas being flown in from Kenya or supermarket vegetables from Chile or wherever. However, large plots were often snapped up by builders for two or three houses so time and time again we would be outbid. We also had a fairly tight search area as we wanted to end up close to our two young grandchildren. In the end we gave up on the new build and chose a property with a substantial garden, in a great location close to our grandkids and a house that we knew we could make substantial changes to - without fear of Listed Building Status or other severe restrictions.


Did you have any issues getting your planning permission granted or with building control?

We did not have any major problems with the Planners. 

We were proposing to change a brick built house with a tile roof to render and slate and the Planners were keen that we retained the look of a brick plinth – we took that advice and were pleased in the end that we did so because, in our opinion, it provides a significant improvement to both the look and the functioning of the house.


Why did you choose your method of construction?

Fabric First was one of the key messages that we took away from NSBRC. We had to get the U values right on the whole of the envelope – the walls, the windows, the floors, the roof. Although the existing house had a double skin wall with cavity insulation, the cavity was narrow – after much research we settled for external wall Insulation because this achieved good U values, did not lead to loss of internal room space and the existing brick walls would work like a massive storage radiator, evening out any changes in temperature. We chose dual-density Rockwool as a better option than oil-based products like Celotex; and elected for a Baumit acrylic through-colour render. For the extension we chose timber-frame (our engineer advised that the existing foundations could take timber-frame for the extension but could not take the weight of brick and block). High levels of Rockwool insulation in the timber frame would achieve a similar U value to the rest of the house. The existing Crittall windows and doors had notoriously poor insulating properties – following wide ranging estimates we went for triple glazed aluminium frames with thermal breaks. For the existing ground floor, we aimed to get as much insulation in as possible – initially we tried to remove the screed but this proved impossible so we brought the floor levels up with Hexatherm XChip insulation. We planned for 26 in-roof Solar PV panels which actually form the weather surface of the roof and combined that with slates rather than tiles – partly for the look and mainly because of the total weight requirements on the existing roof trusses. We extended the roof trusses out to give the shading of south facing windows and also to accommodate the Solar PVs. 300mm of fibre-glass loft insulation completed the insulated envelope together with miles of tape to provide good airtightness.

We did consider such things as solar thermals, air source heat pumps, biomass boilers, underfloor heating – but elected for all PVs because, with good insulation, we did not need a great deal of space heating and it is best to concentrate on producing high grade electrical energy which has many uses, rather than low grade heat energy which has only one use – heating.


Did you use a project manager, or did you choose to self-project manage?

We self-project managed. We had excellent plans drawn up by our architect from which, given time, we could read off all the materials and we sourced these by competitive quotes. We employed all the contractors on day rates.


What was your budget and were you able to stick to it?

£250,000. We formed the budget with the help of a Quantity Surveyor and although we hoped to come in lower, his estimates were close to the actual costs.


If you didn’t stick to your budget, what was the main reason for the overspend?

We planned to convert the brick-built garage into the extension of the house. We were, however, advised by our engineer that the brick walls of the garage were not substantial enough to take the 2-storey extension, so we had to take down the garage and build up from the foundation with timber-frame.


What is the value of the property now?


We spent about £46,000 on the environmental features - rainwater harvesting system; mechanical ventilation and heat recovery system MVHR; external wall insulation; triple glazing throughout; Thermaskirt radiator system; 26 Solar PV System; Earthborn paints; fees for environmental consultation.

This is a significant cost to us, however, the running costs of the house are now very low because we have use of rainwater, we are well insulated and we have up to 6.75kW of solar power at our disposal – sufficient to power the house and fuel an electric car. Water, petrol, gas and electricity bills are greatly reduced. The pay back on most of these environmental features is between 8 and 15 years. We certainly hope to be here longer than that, so we consider this a reasonable financial investment as well as achieving our environmental aims.


Were you able to reclaim the VAT, and if so, how much were you able to reclaim?

We could not reclaim VAT – because this is a renovation project. We realised that to save the VAT we would need to demolish the existing building down to ground level; we considered this and it may have saved us money if we had done so, however, the existing building was sound and well-built according to our engineer and, on environmental grounds, we did not wish to generate the large amounts of waste that total demolition would cause. Like many others we consider that VAT on a project like this is very discouraging – if the Government were serious about the climate emergency, they would encourage homeowners to insulate and engage environmental features. VAT puts people off as does the fact that various incentives have been progressively removed such as: 5% VAT on Solar Panels and insulation has gone, Feed in Tariffs on electricity generation has gone, support for electric cars reduced etc. The Government talks about reducing emissions but is doing progressively less to encourage homeowners to improve the existing housing stock and less to encourage house builders to improve new housing stock. That needs to change in our view.


What aspects of the process did you find stressful – and do you have any tips on how to avoid the pitfalls you encountered?

Making sure that you get the right materials and equipment and that you can get it at the right time and at reasonable cost. Takes a lot of time to work it through if you have not done it before – make sure you set time aside.

Hitting major snags which could have stopped us or delayed us thus adding to the bill. For example, we hit a large underground concrete pad which was on the proposed route of services and drains – we tried to go through it with progressively larger jack hammers and eventually gave up and put services round it. There will be unforeseen snags, particularly underground – make sure you are prepared for this and flexible enough to adjust your plans.


What did you find most enjoyable about working on your project?

Keeping to our overall aims in terms of energy efficiency, water capture, reduction of waste etc.

Including personal touches which had meaning and personal attachment for us such as:

  • Finding a second-hand floor which was Canadian Maple and salvaged from a local Sports Centre. It took a long time to repair, lay and finish this tongue and groove flooring but we feel it was worth it because it met our environmental aims; we wanted wood floors but we were concerned about where the wood for new flooring had been sourced and the glues used in engineered-wood flooring so a second hand floor was ideal, and, to top it all this particular floor was the very floor on which we had first learned to dance.
  • Swedish Falu Red on the extension. Caroline’s Mum was brought up in Sweden therefore we have been to Sweden many times and have a passion for some of their style. All rural buildings in Sweden are timber clad and typically red and white. The distinctive red colour comes from a traditional treatment which is based on linseed oil with a crushed biproduct from the copper mines – Sweden has a long history in metal working. We sourced rough cut pine board and batten which was attached vertically and treated with Falu Red.
  • Linseed oil seems to feature quite a lot – not just in the Falu Red – we also treated all the doors and some of the floors with linseed oil (which was grown by a friend of ours). And we used Marmoleum on the bathroom and utility room floors – a form of linoleum which uses oil from linseed rather than fossil oils.
  • The windows are all triple glazed, but we have tried to retain some of the 1950s Crittall look by having the narrow frames and cross bars.
  • Minimising waste – we stripped and retained all the top soils for the veg garden; we retained all building rubble and smashed this up for hardcore for the drive; we retained all the wood from demolition and off cuts for re-use or to fuel the wood burner; we used recycled products, such as the flooring, and we recycled all the waste that we could (metal, cables, wood, glass, card & paper) therefore we only used one skip for the whole project – this for old plasterboard.
  • It was a very exciting day when we received our Energy Performance Certificate EPC which was confirmed at A* with a rating of 105, and our Air Tightness Test was measured at 3.7m3(h.m2) at 50 Pascals.  The EPC confirms that we have done a good job of insulating the property. Our Air Tightness was targeted at 4 (this is roughly on a scale of 0 to 15 where 15 means a very leaky, draughty house and 0 means Air Tight). 4 is quite a challenge for a renovation and more easily achieved with a new house. A Passivhaus would be below 1 and we now know how difficult that would be to achieve. When you are doing all this building work you may be conscious of needing to insulate well and make the building airtight but you don't actually know until you get your EPC and Air Tightness results - so we are pleased and relieved!

What is one of your favourite features about your project?

Our planning was very much function first, however we are both very pleased with the look of the house from the outside and the feel of the house from the inside. Local people call it the Swiss House – where actually it reflects traditional Swedish design.

John spends a lot of time in the utility cupboard checking on the performance of the solar panels, the Iboost, the MVHR and the rainwater capture system. Caroline is more often found musing on the Stairs because the stair well has come out particularly well, including an interior leaded window made for us by a friend.


How did you tailor your home to suit your lifestyle?

We hope this is our home for a long and happy retirement so we have tried to future proof as best we can. The ground floor is level throughout and the recycled maple floor runs through most of it – so we can dance anywhere in the house. The study and its adjacent cloak room can easily be turned in to a downstairs bedroom and ensuite should, in the distant future, one of us not be able to manage the stairs. The routes to front and back door are ramped with no steps – or they will be when we have finished the landscaping! The various environmental features are our effort to reduce our carbon footprint, something we are both passionate about, and we are keen for others to gain from our experience – so we have many visitors who are interested in what they can do to address the impacts of climate change. The Utility room is large to accommodate various environmental features and also to deal with produce from the garden. The house stands on a large plot, part of which is, or will be, vegetable beds to produce as much of our own food as possible. Sounds a bit like the hair-shirted good life but  we are not like that - we are not off-grid and we are very much part of the local community and we see changes of lifestyle as necessary if society is going to look after the planet. We therefore welcome a steady influx of local people who want to have a look to see what is of interest to them.


What would your top tip be for other NSBRC Visitors about to embark on their first self-build, renovation or home-improvement journey? 

Speak to other Self Builders who have actually done things that are similar to what you are planning and then change your plans so you embrace the hard lessons of their experience.

Hopefully you will have just as nice neighbours as we have, because good relations with your neighbours are supremely important – you are bound to make some noise or mud or have some deliveries at times that inconvenience your neighbours. Keeping them informed and getting on with them is crucial and both you and they will hopefully be able to make it work.

Choosing your contractors is critical. Price is of course important but more so are the skills of your main contractor or plumber or electrician or bricklayer or groundworker and their abilities to get on with each other. Yes, get competitive quotes for tasks or labour costs but meet with any proposed contractors, talk at length with them, go and see work they have done and talk to their clients wherever possible – only after that should you appoint them.