John Spittle - UK Representative, Wiehag
www.wiehag.com
Q: The proposed Part Z Building Regulation will focus minds on embodied and whole-life carbon across the built environment – is this a long overdue addition to construction and design thinking?
JS: Yes, and we hope this will provide consistent and science-based rules on calculating CO2 for each product and material.
Q: The debate surrounding structural timber and 18m usage is seemingly only a UK-only one. With tall timber flourishing internationally – is the UK approach likely to change any time soon?
JS: I don’t think the debate about using timber in tall buildings is only a UK one. What is perhaps different is how the debate is approached in different countries. WIEHAG operate around the globe, providing glulam components to larger and taller structures, so we can speak from experience, of how a science-based approach is used to address the many valid questions and concerns. For instance, for the 86m Ascent Block in Milwaukee, a three-hour fire test was carried out on the glulam elements, and the successful conclusion of this enabled the design to be approved. In the wake of the Grenfell disaster, it sometimes appears that the UK government is taking an unduly simplistic, media-pleasing approach to this subject such as the presumption that only non-combustible materials are safe to use in construction – these materials can fail in fire too! The UK has led the world for the last decade in pushing the boundaries with engineered timber products, but now seems intent on regressing back to traditional build, despite the climate emergency. Therefore, it’s hard to see ‘all timber’ high-rise structures happening in the UK soon, until the perceived issues of fire and insurance are properly addressed and resolved, or there is a radical change in government.
Q: Timber is a mainstay of housebuilding in Scotland – what can be done to raise the levels of structural understanding and use of timber in residential projects elsewhere in the UK?
JS: Education is one of the key factors. In the UK, most engineers are only trained on steel and concrete, so university’s need to offer more timber-based engineering courses. Getting more young people onto proper apprenticeships in trades such as timber erectors – this is also vital because a huge chunk of the ultra-experienced workforce will be retiring in the next few years. Educating insurers and ensuring timber frame dwellings are not penalised because of timber construction and educating the end user. For those who say they do not want a timber frame house, I always argue that people are happy with their houses having timber roofs, timber floors, timber internal walls and timber spandrel panels. So why not the inner skin of the outer walls?
The timber industry also needs to ramp up its lobbying of government to counter that of competing products. Apart from offering financial incentives for low carbon structures, the government could legislate that all its new social housing be built using offsite systems like timber frame or light gauge steel frame. This would enable the timber frame providers to invest and ramp up their capacity. Currently the unpredictable nature of the market prevents this. English housebuilders like traditional build because they can turn it on and off easily and at short notice, as demand quickly changes in this sector, using a vast bank of subbies and suppliers. But with timber frame they must commit on a longer-term basis to a smaller pool of providers. Perhaps the skill shortage on-site will help push them more to offsite systems?
