A chara, – It was reassuring to see coverage of wood-frame construction, its benefits and the bureaucratic and cultural challenges it faces in Ireland in Sylvia Thompson’s article (“Can timber-framed homes using Irish timber be part of solution to reduce carbon emissions?”, Science & Climate, May 4th). There are two important details that deserve to be added to her account, in my opinion.
In the article, Des O’Toole says that “48 per cent of all new scheme homes are timber-framed”. This does not, however, account for the fact that the vast majority, if not entirety, of these homes have a masonry outer leaf. As such, they are only 50 per cent wood-frame, and remain a proportionally greater carbon culprit than a true wood-frame house, ie a single-leaf, all-wood envelope construction as is standard in North America, Scandinavia, and Oceania, climates variously wetter, harsher and more extreme than our temperate Irish climate. If we are truly dedicated to using wood-frame to decarbonise the built environment, there should be no such half measures, and wood-frame advocates and detractors alike must take their cues from the world stage when it comes to whole-envelope design.
Later, Marion Jammet of the Irish Green Building Council mentions the lower human- and material-resource intensivity of wood-frame construction. She attributes this, however, to the fact that “most of it is built off site”.
While there are benefits to factory-based wood frame manufacture, the lower human- and material-resource intensivity of the product is equal whether it is manufactured on-site or off-site. There are two main issues with relying on factory-based manufacture. For one, factories themselves require large amounts of capital and carbon emissions to construct in the first place, costs which must then be carried by the customer and the environment respectively. For another, there are vast numbers of site tradespeople in the country suitable for reskilling in wood-frame construction; they wouldn’t all fit in, or even suit, factories. With on-site wood frame construction (the norm in North America and Scandinavia), each site becomes its own zero-cost factory. Exposure to the elements poses no real issue; contrary to popular belief, a wood frame under construction can wet completely and dry completely with no consequences.
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In summary, there is still ground to be made in the Irish approach to wood-frame construction. All-wood envelopes and thinking outside the factory box are a good start. – Is mise,
JACK HANAFIN,
Blackwater,
Co Wexford.
