LEITRIM SCHOOLHOUSE
CASE STUDY
It’s warm, it’s quiet and the air quality is perfect.
S
eán Breathnach’s deep retrofit of a 19th century schoolhouse offers an insight into what might be done with Ireland’s extensive stock of empty stone-built buildings. Working almost singlehandedly, Seán converted a drab ruin into a high comfort home, which is beautiful both inside and out. He estimates that the entire project, including the purchase of the site, cost about €95,000 (though he stresses this is a rough estimate). When Breathnach returned to Ireland from Canada in 2017, the carpenter and newly qualified passive house designer had a very clear idea of what he wanted to do: find a small, dilapidated structure in the west of Ireland and bring it up to Enerphit standard (the passive house retrofit standard). He found the perfect candidate in a schoolhouse perched at the top of a hill in north Leitrim. “It dated from 1870, and it was very cheap, which was great because my budget was tiny. I got it for €33,000,” he says. “What made it perfect was the fact that somebody had already started renovating it around
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2006. They’d cleared out all the old fixtures and fittings. They also re-roofed it, put on new skylights and replaced the lintels in the stone walls.” The most surprising thing about the building was that it was bone dry inside. “The first time I walked in with a friend who lived up there, we couldn’t believe how dry it was. You’d expect everything to be covered in mould. But the roof was sound, and all the windows were broken, so there was plenty of air circulating through it.” In addition, well-draining soil and the elevated location meant that moisture tended to fall away from the site. Breathnach had left Ireland for Canada in 2006, served an apprenticeship as a carpenter and in time became an expert in post and beam construction – what’s known simply as ‘timber framing’ in Canada. He subsequently developed an interest in alternative building systems like straw bale and other natural materials. “The problem was that these projects could be very badly detailed. The concept could be great, but the detailing, particularly in relation to airtightness, tended to be quite poor,” he says. It was in order to redress this deficiency that Breathnach began researching the passive house standard, and ended up taking a passive designer course in Vancouver in 2017, the same year he decided to return to Ireland. Because the Leitrim schoolhouse was technically derelict, he was granted a planning exemption and was cleared to begin work. The school’s outhouse hadn’t formed any part of the aborted 2006 refurbishment and was effectively a shell: four walls but no roof. Breathnach rebuilt the walls of the outhouse, put on a roof, insulated it and moved in. This tiny (nine square metre) building would be
his home for the coming months as he began work on the schoolhouse itself. The plan was to build a new house inside the shell of the old building; a box-within-abox. The exterior walls function as a cladding material, then you have a 40 mm air gap and the interior shell is built out from there, beginning with a weather membrane and 40 mm Gutex woodfibre insulation, while 150 mm of cellulose in the stud takes care of the bulk of the insulation. “Because this kind of build is rare, it’s difficult to know exactly how big that air gap between the stone and interior shell should be, or how many ventilation holes you need,” he says. When insulating internally, there is always a greater risk of creating a dew point for condensation, where the temperature drops suddenly between the new insulation and the old wall. So, Bob Ryan of Earth Cycle Technologies was hired to run a WUFI condensation analysis, which confirmed the integrity of the build-up. In addition, Breathnach, who is studying civil engineering in Sligo IT, plans to conduct a full moisture assessment of the walls as part of his final year dissertation. He also deliberately avoided using concrete as much as possible to reduce the embodied carbon of the build. There is no concrete slab, for example, and instead the beams are supported with a combination of small concrete pads and Mannok Aircrete thermal blocks. Breathnach was able to complete the build with very little help. “You’d be surprised how much you can do on your own if you’re used to it,” he says. “I didn’t have any concrete pours, those pads were small, and it turned out that there was no roofing required at all, which was amazing. I upgraded the glass in the skylights, but that could be done from the inside. In terms of other