The project was funded under Sustainable Energy Ireland’s (SEI) House of Tomorrow programme, the scheme for promoting greener practises within the building trade. Grant aid of up to €8,000 per unit is dependent on the degree to which the house exceeds building regulations and incorporates innovative technologies.
This is the first time Heneghan took a sustainable approach to a multiple housing development. “We would have built a lot of houses in north Mayo over the last ten years,” he says, “and in the last five, we built a couple of houses that would have had geothermal or solar. I became interested in it and started looking at the idea of doing maybe a small estate.” The twenty-seven timber frame houses combine individual geothermal heat-pumps with solar panels for space and water heating. High spec windows, doors and insulation work with a mix of underfloor heating and outsized radiators to deliver and conserve heat. All architecturally designed, the houses incorporate a number of features which work to minimise heat loss.
Though a convert to the sustainable approach himself, Tom Heneghan admits that it wouldn’t be particularly fashionable in his neck of the woods. “I’d always go to Plan Expo,” he says, “and over the last ten years you’re seeing more and more systems…The first years you’d maybe get one guy there with solar panels and one guy there with a heat-pump. You’d nearly pass them by and say what the hell is he doing here? But as it went on, up to maybe five years ago, there were five or six different companies doing the same type of thing. You’d read the literature and see that these systems were over the world.” Change however doesn’t happen overnight. “The timber frame house, we had never done that before. We’re in out the wilds here of west Mayo. People would question a timber frame house, so even that was a kind of a leap forward.” But over the past twelve months, the combination of SEI’s Greener Homes scheme, the energy crisis and rising public awareness means Heneghan has less explaining to do when it comes to showcasing the development to the house-buying public.
Architect Jim Drew of Vincent Hannon & Associates explains that before planning began, the team sat down with SEI to work out how the development could achieve the 40% above regulations required to qualify for the maximum House of Tomorrow grant. Besides establishing target U values for all external surfaces, design imperatives were also considered. “We made sure doors didn’t open direct to the outside air.” Drew explains. “From the hallway, you had a porch and the porch to the rear was achieved via the utility room; the utility room had a door going outside and a door going into the kitchen.” Given the nature of the site, planning for passive solar gains proved difficult. “The sites are to some extent linear from the main road, so we had to comply with the planning requirements in terms of the roads…We were limited on the orientation, but what we had to ensure obviously is that we had solar panels on the south elevation which meant that we had the solar panels on the front of the houses.” Though planners prefer to see panels to the rear, many local authorities are becoming accommodating if that isn’t practical.
Mike Cruickshank of ScotFrame provided the timber frame. “What we supplied was 45mm by 140mm external timber frame walls which are insulated with 150mm mineral wool quilt.” In the roofspace, two layers of 150mm mineral wool were crosslaid, giving a total insulation depth of 300mm. As an additional thermal and sound insulation measure, 100mm of mineral wool were also inserted into internal walls. The timber itself is Scandinavian timber carcassing. “It’s a standard that’s used by most timber frame companies.” Cruickshank explains. “The only difference is we tend to use 45mm timbers rather than 38mm timber for our walls. It just gives you a better fix for your plasterboard so you tend to get less popping on nails and also it gives you approximately 18% more timber in external walls.” The company also supplies a breathable roofing felt which removes the need for ventilation in the attic spaces.
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