NSBRC - Clive Spencer

Clive Spencer - Case Study

Could you tell us any interesting facts or remarkable features about your project?

The aim of the project was to produce a healthy, uplifting and highly sustainable new home, but this process had to start with the removal of the old bungalow, which we had established was beyond economic repair. We wanted to recycle as much as possible, so we started by salvaging and selling the wood burner, wrought iron railings, hot water cylinder, all other metal and wiring, polycarbonate roofing from the carport, all roof tiles and even the walk in bath. Unfortunately we could not salvage the period kitchen, as it had been badly damaged by damp and rats. We de-nailed as much timber as possible for sale and the timber that was not suitable for this process was taken away by a local wood recycling company. The UPVC windows and doors were deglazed and recycled too. The standing walls, which were almost all concrete block, were crushed and used as hardcore for the new house and driveway. None was removed from site. No excavated soil or stone was removed either and as a bonus we now have quite an impressive rockery, which is a haven for wildlife. We ended up using two skips, mostly to remove a relatively small amount of plasterboard from the ceilings and for the rubber membrane and compressed straw roof board that had been used on a large flat roof extension.

The new house was constructed with a timber frame. The primary insulating materials used in the walls and roof were Warmcel, which is a Natureplus certified product composed of recycled newspaper, and Pavatex insulation board, made from untreated compressed wood fibre sourced from sawmill offcuts and chippings. Fermacel was used throughout the interior, instead of plasterboard, which not only has better eco credentials, being made from recycled gypsum and recycled cellulose, but also offers better fire protection, an improved acoustic performance, has greater strength and a higher thermal mass, which is an important quality in a lightweight timber frame construction. We kept the house carpet free to efficiently use the thermal mass provided in the floor structure too. Space heating and hot water are provided by an air source heat pump and internal ventilation uses a mechanical heat recovery system with metal ductwork, which avoids the use of plastic and has no issues with off-gassing. To keep the internal environment as healthy as possible, all paints are eco water based and emulsions are derived from clay, both of which are breathable and free from any nasties. The first floor balcony was constructed of galvanised steel and designed as a free standing structure that was bolted to the house, this avoided the use of any cantilevered components that would lead to thermal bridging.

We were keen to not use MDF in the house, so a plywood kitchen appealed to us. We scanned the country for suppliers, but realised we could cut down the road miles and save money, by getting a local carpenter to make it for us. We have a 3500l rainwater harvesting tank, which was primarily incorporated to irrigate our two allotments, although it has also been routed into the house and can be used to flush toilets. A photovoltaic array was installed on the flat roof, although I am still waiting for battery technology to improve and prices to fall before installing one. All appliances and lighting are rated at A+ or better and we do not have a tumble dryer, as the laundry room has drying racks.

After taking advice from a number of people with experience of Passivhaus buildings, I decided not to install underfloor heating, but instead used radiators. They are relatively large, to compensate for the air source heat pumps lower flow temperature, but we have been extremely happy with the responsiveness they provide and as all surfaces in the house are within a degree or two of each other, floors never feel cold.

During the design phase, we were advised that the Passivhaus Planning Package (PHPP) had highlighted a risk of overheating, so we incorporated an external blind on the largest east facing window, as overhead shading is relatively ineffectual on east and west facing elevations, whilst an oversailing roof detail was used to shade the south facing clerestory windows. Another measure that was taken to protect against overheating was the inclusion of effective ventilation, with most windows having the option to open. The problem of overheating highlights the importance of using the PHPP in the design process and we have been very appreciative of the features that have been incorporated to address the issue. The more obvious solution of reducing the glazed area was something we wanted to avoid, because of the far reaching views we are lucky to enjoy.

The self binding gravel for the driveway avoided using higher embodied carbon alternatives and although we were advised that it may have some drawbacks when used in conjunction with vehicular traffic, we have been very pleased with our choice. Another area where we wanted to make carbon savings was by furnishing the house with as many secondhand items as possible. Conveniently we had chosen a midcentury theme and although it probably did take longer than buying new, eventually we were able to find the majority of the items we wanted on the secondhand market.

Our data collection has shown, compared to the UK average dwelling, we are using 88% less energy for heating, 75% less total primary energy, whilst water consumption is more than 50% lower. Our final airtightness test result was 0.3 air changes per hour, twice as good as that demanded for Passivhaus certification. Monitoring over a 12 month period has also shown the house to be carbon neutral (excluding plug loads) and energy use for heating, per square metre of treated floor area, is within the figure required for a Passivhaus.

Floorplans & Elevations

Clive's Experience at the Centre

How many times have you visited The National Self Build and Renovation Centre before?

I have been to the NSBRC at least 10 times.

What would you say is the most helpful feature or resource at the NSBRC?
Having a large permanent display of exhibitors is very helpful, but I found the courses and workshops most useful.

Did you use any exhibitors at the NSBRC? If so, who?

Green Building Store, Internorm, Warmcel and Vastern Timber.

What did you enjoy most about your visit to the NSBRC?

The aspect that I enjoyed the most, was being able to meet so many helpful and knowledgable people, especially those involved in the training courses and shows.

Would you recommend the NSBRC to a friend, and if so, what aspects of the Centre would you recommend and why?

I have found having an understanding of the building process to be extremely useful and because the NSBRC is such a good place to acquire information, using any or all of the options mentioned above, I would recommend it to anyone without hesitation.

Clive's Self Build Journey

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

With the current concern for the deteriorating state of the planet, my inspiration for the project was to construct a new home with a low ecological footprint. As Passivhaus is the world’s leading standard in energy efficient construction, it seemed obvious to build to this standard. After contacting Warm, one of the countries leading Passivhaus certifiers, a Bristol based Passivhaus designer was recommended, who happen to work with a local construction company with experience building to the standard I wanted and in the process, had achieved some of the most airtight structures in the country. Due to this level of expertise and the fact that the designer was going to be using the PHPP during the design process, I decided to forgo certification. This decision was very carefully considered, as Passivhaus certification ensures that a building performs as designed and with many people promising to construct using Passivhaus principles, but not necessarily committing to the very rigorous requirements Passivhaus calls for, there is much scope for performance shortfalls and overheating.

What was the cost & size of the land?

The cost of the structurally compromised 1930s bungalow, with no heating or hot water and major damp problems, sitting on 0.5 of an acre, was £365K.

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

I spent 12 months monitoring a number of property search engines, as well as numerous auction companies. Eventually I found my current site on an auction website.

For others currently searching for plots, I would recommend widening your search parameters as much as possible. Even though my only real requirements were a good outlook, in an area that covered southern England, it still took a considerable amount of time and effort to find a suitable plot.

Did you have any issues getting your planning permission granted or with building control? If so – why was this?

Wiltshire planning and building control were both helpful and supportive. The small number of issues that needed addressing were with the local community, either directly, or through the parish council. I have found this to be a very grey area and one that needs careful consideration as to how much influence you allow it to have on your project.

I think the fact that I was proposing an unusual design of house made it more controversial for some local residents, but at the same time, the fact that a lot of the motivation for that design was to do with sustainability and high levels of energy performance, may have made it more appealing to planning.

Why did you choose your method of construction?

Timber frame offers a low embodied carbon and sustainable construction method. Even though it increased the cost, we opted for a stick build timber frame, rather than panellised construction, as restricted access prohibited very large vehicles accessing the site.

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

Most of the project management was carried out by our main contractor, although I did take on a number of elements, which I managed myself.

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

During the design stage, it became necessary to increase our preferred budget. For the house itself we settled on approximately £2500/m², excluding the kitchen and a few other elements that I took on myself. The carport, garden studio, landscaping and planting were all additional costs.

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

The increase in budget was partly because of rising material and overhead costs, but was also necessary in order to achieve the high performance targets I wanted for the house and to maintain the use of durable, high quality materials, rather than resorting to cheaper, inferior products.

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

As most of the VAT was dealt with by the main contractor, we only claimed back approximately £1000 of VAT. The figure was also low because the majority of the products I sources were zero rated for VAT, as a result of our new home status.

Our claim was dealt with quickly and was very straightforward, but I would recommend that those undertaking a self build read the gov.uk website guidelines before the start of the project, so that you know what is eligible and what is exempt.

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

Having completed three self builds over the last 25 years, I have learnt that there will always be stressful moments and this project was no exception.

We had the initial dilemma over the budget, there were a few hiccups with the construction itself, mostly caused by one supplier and one subcontractor, but they were all overcome, although I found the time this took to be a particularly stressful element. The global pandemic and Brexit were other factors that complicated the process, but we consider ourselves fortunate to have successfully come through the process in spite of them. I would also add that we were very grateful to have chosen a tenacious main contractor.

The advice I would give to others would be to be meticulous in your planning, keep good records, but above all be well informed about the process. The NSBRC is a good resource to help you achieve this. Hopefully you will then have an informed opinion about aspects of the build you are concerned about and feel confident to highlight them.

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

Apart from being able to sit in a house that has been designed to our exact needs, the most enjoyable part of the project for me was working with all the people who made it possible.

What is one of your favourite features about your project?

If I had to choose one aspect of the project to be a favourite, it would have to be that the house falls into the top few percent of dwellings globally, in terms of ongoing energy usage. The fact that it is also a very uplifting and healthy environment with a captivating view are wonderful bonuses.

How did you tailor your home to suit your lifestyle?

One thing we wanted to achieve was a future proof home, particular as the sloping site lent itself to an inverted living arrangement, with living accommodation on the first floor and direct access from street level.

We achieved this by including one bedroom with an ensuite on the first floor and ensuring there was wheelchair access to all rooms and the balcony on this floor. I wanted to keep the house relatively compact, not only as there are only two of us in residence, but also to avoid the waste of energy associated with a larger floor area. We do however have a large number of family members and friends who come to visit and we wanted to include a number of additional rooms, one for my partners alternative therapy practice, a lounge area that was directly accessible to the garden and a home cinema. We addressed the problem partly by reducing circulation space to a minimum, but mostly we achieved it by having rooms with more than one function. The office doubles as a treatment room and bedroom two has seating for use as a reception room, with direct access to the garden, all the necessary infrastructure incorporated for a cinema, and a sofa bed when we need a guest bedroom. We are both keen cooks and the bespoke kitchen is something we are extremely pleased with, as is the inclusion of a pantry, a feature that we would now not want to be without.

The main motivation for purchasing the plot is the far reaching view it has to the east. To make the most of this view and to overcome the issue of access to the outside at first floor level, which is an important requirement for us, we included a balcony. The last item that I wanted to include was a laundry with drying racks. I read that when an MVHR system is installed in a house, the fact that the air is extracted from wet rooms, such as laundries, means clothes can be very effectively dried, with none of the normal concerns of mould and poor air quality. It works brilliantly!

Is there a possibility you would ever undertake another project in the future?

Never say never. The category of Passivhaus Premium, which produces far more energy than the house can use, has already been created and with the worsening situation the planet is predicted to experience, it has to be a target to strive for.

If so, is there anything you would do differently?

If I were to build again, I would look for an alternative to concrete foundations, investigate recycled steel, modular offsite construction and look into the use of highly sustainable building materials, such as clay, cob and straw. I would also want the house to be carbon neutral and a net producer of energy.

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

Other than the obvious advice of not changing your mind on the specification during the construction stage, my top tips would be to include a Mechanical Ventilation and Heat Recovery system (MVHR) into any new home and to go for a fabric first approach. It is so important to get the main structure of your house built to the best possible standard, rather than trying to make up for deficiencies with lots of green technology. Also, prioritise getting details right that cannot be easily changed or upgraded at a later date.

If you are building a very high performance home, especially if you are not intending having it Passivhaus certified, I would advise using experienced contractors with a proven track record and insist that your designer or architect uses the PHPP during the design process. Ignoring problems such as overheating will definitely be something you will regret. With every planning policy update moving closer to Passivhaus, it increasingly makes sense to build to this standard. If like us, you decide to go in this direction, I would suggest you seriously consider certification. We were fortunate that our contractor delivered the performance standards we had hoped for, but to help ensure you reach them, certification overcomes the problem of performance shortfall.

Finally, I would recommend you resist the urge to install a wood burner into a very high performing home or Passivhaus. MVHRs are brilliant at recovering heat from the extracted air, but not so effective at moving large amounts of heat from one area to another. You will end up with one very hot room, not a warm house.

Clive Spencer

Clive Spencer - Case Study

Floorplans & Elevations

Clive's Experience at the Centre

Fact file

Clive's Self Build Journey