Building tall in timber has been enjoying a renaissance in Europe and North America since the 1990s. Today, medium- to high-rise rise apartments and offices are being built in engineered – or mass – wood, mainly glulam and cross laminated timber (CLT). Mass wood buildings are now exceeding 80m in Europe, but in Ireland, our building regulations restrict the height of timber buildings to 10m.
Countries including Canada, the US, Germany, Austria, Sweden, Netherlands and Norway are creating a revolution in building tall in mass wood, which is playing a major role in decarbonising the construction sector.
Further expansion of mass wood construction is forecast because of changes to building codes. Meanwhile, Irish building regulations continue to ignore European and international advances made in mass wood buildings, especially in relation to fire.
A number of Irish and international experts discussed the opportunities and barriers facing wood construction in Ireland at the recent ‘Build with Wood – Pathway to Net Zero’ seminar in the Coillte’s Visitor Centre, Avondale Forest Park.
The seminar, supported by the Department of Agriculture, Food and the Marine (DAFM), Coillte, and Enterprise Ireland, explored issues such as the removal of barriers to timber usage in both timber frame housing and medium- to high-rise apartment and office construction.
The exposed glulam 25m Sitka spruce beams – the longest in the world according to Imelda Hurley CEO Coillte – in the Avondale Visitor Centre illustrates the enormous potential of home-grown timber in mass wood construction in Ireland.
Timber demand will continue to increase as “the World Bank forecasts a quadrupling of global wood fibre demand by 2050,” said Hurley.
“Globally, construction and the building sector represent 38% of the world’s energy related carbon dioxide equivalent (CO2eq) emissions and reducing the carbon footprint of our future building stock is key to tackling climate change and achieving Ireland’s net zero ambitions,” she said.
There are opportunities for home-grown timber if Ireland is to build an estimated 50,000 homes a year, which will be required to meet housing demand, according to a recent report by Irish Institutional Property (IIP).
It’s likely that a shortage of timber won’t be a problem at least up until 2035, when annual timber supply is forecast to increase to 7.9m m3 on the island from 4.5m m3 at present.
Achieving greater market share for timber in housing was outlined by Minister of State Pippa Hackett, who said she will be discussing this in an upcoming meeting with Minister for Housing Darragh O’Brien.
“Building with wood reduces our dependency on fossil-based materials at a time when we need to do everything we can to reduce our greenhouse gas emissions,” she said.
Timber frame construction
While the conference focused on mass wood, increased use of sawn wood in timber frame housing is likely to be the medium-term goal, as Ireland lags well behind Europe in the timber frame market.
Timber frame as a Modern Methods of Construction (MMC) is the most sustainable building medium, according to Heber McMahon, director of sales at Cygnum Building Offsite, the Macroom-based timber frame processing company. The theme of McMahon’s presentation was ‘Building, faster, more efficiently and more sustainably in timber frame’.
MMC timber frame construction places strong emphasis on the use of technology in a factory-controlled environment. This provides a product “within one millimetre accuracy using CNC [Computer Numerical Control] equipment,” he said.
“This gets rid of waste and improves efficiency, safety and increases the speed of construction with low labour input,” he added.
“For example, a four-man crew can build four houses in four days.” While mass timber is ideal for medium to high rise buildings, McMahon said that timber frame is suitable for seven storey buildings, which is three storeys higher than the current building regulations allow.
The benefits of mass wood in displacing fossil-based material were outlined by Kelly Harrison, director of Whitby Wood Architects, in her presentation ‘Pathway to NetZero – The Sky is the Limit’.
“We need buildings with least embodied carbon and there is no viable alternative to wood at the moment,” she said. One of the attractions of wood is its flexibility, she claimed.
“In addition to building new projects in wood, we also use mass wood for its refurbishment potential in adding storeys to concrete buildings.” She outlined how a Whitby Wood project in Chelsea “added four storeys in mass wood using CLT and glulam on top of a two storey concrete building”.
Her company has been “breaking myths” such as timber’s vulnerability to fire, where “mass wood chars to protect itself”, a view shared by Dr Mila Duncheva, business development manager with Stora Enso Building. She outlined key turning points in Sweden’s fire regulation history.
“Sweden opted for a step-by-step performance-based regulation approach for timber rather than prescriptive legislation,” she said.
“Comparing the difference between the same buildings in steel, concrete or wood and seeing how they perform,” was part of the exercise.
“The aim should be to provide guidance that answers simple questions that everyone can understand, so there needs to be clarity regardless of the rules.”
This should be shared with the relevant regulatory and approval authorities in Ireland as a matter of priority
Jarrett Hutchinson, executive director of the Office of Mass Timber Implementation, British Columbia (BC) agreed with the step-by-step methodology, or in Canada, a province-by-province and a cross-government strategy.
As a result, schools and even fire stations are now building in mass wood. In BC, where Hutchinson played a major role in developing the province’s ‘Mass Timber Action Plan’, there are currently 313 mass timber projects, which is more than all of the US.
Des O’Toole, marketing and communications director at Forest Industries Ireland, who organised the conference, told the Irish Farmers Journal that the sector needs to learn from countries which have strong wood cultures.
“We need to update fire resistance standards and funding should be made available to collate all existing international large scale fire test evidence.
“This should be shared with the relevant regulatory and approval authorities in Ireland as a matter of priority,” he said.