An Energy-efficient Contemporary Self-build

"The global recession and banking crisis had us seriously considering moth - balling the half-finished build and staring into the financial abyss,” says Don McLean, describing the tribulations of his and wife Lorna’s self-build project. Looking at the finished house – a fine example of low-impact contemporary design in the heart of a posh Glasgow suburb – it’s difficult to imagine that anything remotely unsettling could have happened along the way, for this appears to be a master class in good planning. There’s a big part of Don, though, that is just glad the whole thing has been completed.

“We had been making plans to build for a while, and when we saw a pretty sorry, run-down timber bungalow with what might best be described as an ‘unusual’ two storey rear extension, on the market, we decided to go for it,” explains Don. “We wanted to stay in the area, which is perfect for us — close to the city but on the edge of the countryside. We knew full well that we would be able to demolish it and build something in its place, and managed to purchase the property. We had a house just down the road and, thanks to BuildStore’s Accelerator mortgage, we could stay in it while building this one.”

So far, so straightforward. Don, an architect, came up with ambitious plans for a contemporary home on the sloping site that, in addition to being a beacon for cutting-edge design, would also be a standard-bearer for energy efficiency. “There were many constraints with the site – not least its size, its sloping nature and the fact that any development would have to take into account the needs of its neighbours – but I happen to think that constraints actually bring out the best in house design, and I think the end result proves it.”

Fast forward to autumn 2008 and, with work halfway through on site, the global credit crisis hits, and while bankers are being turfed out of offices in Canary Wharf, of more pressing concern to these Glaswegian self-builders is the turmoil in the mortgage markets. “Our lender, TMB, got sold to Birmingham Midshires,” Don explains, “which didn’t seem initially too concerning, until we received a letter saying that they were reviewing all of their development business, and when we needed an extra facility (something we’d previously agreed wouldn’t be a problem) said that they would be happy to help — at 9%.”

Don gives an edgy laugh now but it’s easy to imagine the kind of effect that news can have on a project. “It was simple — we had to beg, borrow and steal all the money we could lay our hands on,” he says. “It added immeasurably to the stress of the entire affair, but luckily we managed to keep things moving.”

And it’s a good job they did, because the house that Don and Lorna have built is really an example of how modern homes should be built. First of all, it is completely site-specific. The plot slopes upwards from the front and levels off to the rear, and so the design features a semi-basement garage space coupled with an upside-down floorplan arrangement, so that the open plan living space (kitchen, dining and living) upstairs can make the most of the views of the city to the south and the hills to the (rear) north.

Secondly, the house looks great — in complete contrast to what was there before and, it has to be said, a shining light in a neighbourhood of pleasant but modestly designed homes. Its clear modern lines are clad in a mix of cedar (varnished three times) and self-coloured Sto render, while the shallow-pitched roof, clad in terne-coated stainless steel, enables the maximum internal volume to be used. Cleverly, whilst it feels like a large house (it’s 220m²) it doesn’t overpower its neighbours in any way.

Thirdly, and most importantly, it performs incredibly well. This has to be the greenest house in Glasgow. Don and Lorna chose insulated concrete formwork (ICF) from Beco Wallform for the structure of the walls, because it’s fast, heavily insulated and provides a much better basis for creating an airtight construction. “The ICF is also intended to increase longevity,” Don continues, “thus reducing the site’s ongoing carbon footprint.” What’s more, in addition to the incredibly low external wall U-value ICF enjoys (0.19 — just over half the current Building Regulations requirement), it enables the house to benefit from solid concrete intermediate floors, which help it to store energy from all that south-facing glazing. The roof overhangs to the south to provide shading in summer (when the sun is higher) and, when the sun is lower in the winter months, passive solar gain.

Don and Lorna opted for an air-source heat pump – Mitsubishi’s Ecodan HW140, which kicks out between 5-14kW at a (manufacturer’s claimed) average Coefficient of Performance of 3.16 (i.e. for every 1kW of input energy, it outputs 3.16kW) – to provide their water and space (underfloor) heating. It sits in their garden (it churns away pretty silently) and cost a little under £4,000, taking into account a 30% grant. They don’t have a boiler but they do have an immersion heater for backup (“we haven’t used it yet,” says Don), with the heat pump feeding a large 250- litre thermal store. Likewise, the house has been built with airtightness at the forefront of their minds — even the Scan 50 woodburning stove (“again, it’s rarely on, but it does provide a nice focus,” says Lorna) has been provided with its own fresh air source direct from outside, to prevent draughts being induced and drawn through the house.

If it all sounds like boy’s toys, well, to an extent, that’s fair game — but it’s also true that these days a house is measured not just by the way it looks as much as the way it performs. And this house performs brilliantly. “It’s 30% bigger than our old house,” explains Don, “and whereas our old bills totalled £200 a month, now we’re paying £125 a month.” Taking into account the size differential, that’s a saving of £1,620 a year. If you assume a conventional boiler might cost £1,200, offsetting that £4,000 initial outlay down to £2,800, that means a payback of less than two years.

The result is a real victory for the determination of a couple of self-builders. Design finesse is everywhere, from overhead natural lighting in the kitchen to the 90° angle of the roof (giving the rear wall its unusual appearance), but this is clearly a successful family home (so successful that adult children are now coming back to live) and, in particular, the top floor space feels a world apart from its suburban surroundings. A modern eco home that pushes the boundaries to overcome a credit crunch — if ever a house sums up self-build in 2009, this is surely it.

ABOVE: Don and Lorna bought this timber frame bungalow (TOP LEFT) with a view to replacing it with something more contemporary. Demolition took just one morning. Their new home is built using insulated concrete formwork (ICF) from Beco Wallform.

Further reading:

• View a short video about this award-winning home
• A Low-Impact Eco House
• An Eco House Built for £60,000

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