A Passive Solar Self Build

The house was designed by their architect son, David, and built mainly on a DIY basis, with John doing most of the carpentry whilst Joan undertook the landscaping. The property is built following the passive solar house design; built over three levels and including a partial basement to make the most of the sloping site.

Over time the couple began to find it increasingly difficult to take care of so much land, however, and decided to try and build a more manageable house - something which they had discussed over a number of years. Their son David is an architect, and company director of architectural practice The Genesis Design Studio, and John and Joan asked if he would design them a new home in the garden which would be suitable for their retirement.

David Barnes applied for planning permission to build two houses to the rear of his parents' property, but this application was initially refused because the Local Authority did not support backland development at the time. "We had to go through the appeal process," says David, who finally won the appeal in 1999. "One house was built, and permission exists to build a second house in the future - although my parents currently use this plot as a lawn."

The new house has been designed to exploit the slight slope of the ground and the southern aspect. A partial basement was built to maximise and overcome the sloping site, and the mass of the brick and block building helps to control daily and seasonal temperature swings.

Built over three levels, the house appears to be a small single storey bungalow from the entrance, with only a few small square windows punched into the masonry to avoid directly overlooking the Barnes' previous home. The rear of the house faces south, and has extensive glazing to make the most of the views and passive solar gain from the sun. Patio doors open onto a balcony at ground floor level, with all habitable rooms arranged on the south and fully glazed.

A two storey high conservatory is also incorporated on the southern side of the house, and door openings into this space allow warmth from the sun to work its way up into each level of the main building, with automatic temperature and rain-sensitive opening vents in the conservatory to prevent overheating. A Velux window above the back staircase also draws warm air up and out of the building to cool it when necessary.

Ground floor living rooms benefit from the wall of glass and a full length balcony, part of which is external, with a central section contained inside the conservatory. John and Joan use the basement conservatory as a sun-lounge, which is overlooked by an internal balcony where they can sit and eat breakfast.

"On the whole we managed to agree about most things, although David would have liked us to keep the ground floor living space totally open plan," says John, "but we decided to separate the sitting room from the kitchen and dining areas to allow us to use the rooms independently."

The three bedrooms and two bathrooms utilise the full shape of the roof, and have high sloping ceilings and exposed glulam (glued laminate) beams, with a strip of Velux windows which reach down to the floor - affording views south across the Wiltshire Downs.

When the Barnes had built their previous house they lived on site in a caravan, and John had undertaken all of the building work - even making the doors and windows in his workshop. This time, however, he and Joan were able to stay in their own home while the build progressed.

The basement level has been constructed with a pre-cast concrete beam and block floor, and the external cavity walls were built with a dense blockwork inner skin, 103mm of Ibstock's Chailey Hamsey stock facing bricks and a 150mm cavity, fully insulated with Rockwool cavity wall batts. Unusual black glazed interlocking clay pantiles were chosen to complement the grey concrete tiled roof of the existing house, and the windows are a combination of internal softwood and low maintenance aluminium on the outside, built in accordance with David's details with low emissivity, argon-filled glazing.

"We intended to employ builders and subcontractors to build the house for us, but it didn't quite turn out as planned," says John Barnes. "Our son-in-law did most of the brickwork, but by the time we got up to roof level the builders were scratching their heads over how to bolt glulam beams together. We were getting frustrated by the lack of progress and, as I'm a qualified joiner, I decided to help them out. From there on I became more and more involved, and ended upon doing quite a lot of the internal carpentry myself as well."

The Barnes' house is highly insulated and has a solar panel to assist with heating the hot water, which is expected to reduce costs by around 50%. Zoned underfloor heating is used throughout, which allows lower water temperatures in the heating circuits and suits low condensing boilers. Rainwater is collected from the roof in an underground garden chamber to be filtered and recycled for toilets, the washing machine and garden watering, saving the couple a significant amount on their bills.

Ventilation is achieved by a continuous ventilation system with heat recovery which, as well as preventing heat loss, also substantially reduces draughts and moisture content. This improves air quality which, coupled with the use of tiled and laminate flooring, reduces the occurrence of house dust mites which could trigger Joan's asthma.

"John has always been keen on new technology, and wanted to introduce as many energy-saving devices as possible," she says. "Some had to be discounted because they were too costly, but we may add photovoltaic panels and possibly a wind turbine in the future."

Internally, the house has been painted white with modern fixtures and finishes. The striking three storey timber staircase has open treads with glass balustrades, and is lit by the small square windows and from above by triangular glazing in an artificial vent over the stairwell, lined internally with shelves to display Joan's collection of plates.

John fitted the kitchen cupboards and built units in the sitting room to accommodate his newly purchased plasma screen TV. He also made the bathroom units, with wall-hung toilets and inset sinks, and chose lever taps for ease of use and a corner bath with a built-in seat in the main bathroom.

"We started out wanting a smaller, more manageable property for our retirement but have actually ended up with a larger house than before," he says. "The layout allows us a certain amount of flexibility, and although we currently use the basement level as an office and workshop with a conservatory sun-room, this could easily become bedrooms or a self-contained unit depending on our needs in the future. I'm no spring chicken - although I do still feel like one occasionally - but our self-build project was certainly an interesting challenge at my time of life."

Further reading:

• Alternative Heating Sources for Self Build Homes
• An Eco Self Build in Devon
• A Super Insulated Self Build