NET ZERO TARGETS
DELIVERING LARGE-SCALE LOW-CARBON BUILDINGS
01 Christian Dimbleby, Associate, Architype, explains how timber is increasingly being used in education buildings to create low-carbon and healthy spaces for staff and students. At a time when climate change is at a critical level, the construction industry is faced with intense speculation as to its approach when reducing environmental impact in new buildings. It is essential that architects and others involved in designing the built environment tackle this challenge head on. When it comes to ensuring net zero carbon buildings, timber plays a key role. What do we mean when we say lowcarbon design or ‘net zero carbon buildings’? The UK Green Building Council splits the definition up into two sections – construction and operational energy. This is an important distinction, as currently UK Building Regulations only focus on operational energy
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through Part L requirements, which themselves are nowhere near stringent enough. Although approximately 28% of global carbon dioxide emissions come from building operations, a further 11% comes from building material and construction often referred to as ‘embodied carbon’ or, as a recent trend has defined it, ‘upfront emissions’. When you look at the impact of new construction over the next 30 years to 2050, the role of building materials is significantly more important than building operations by up to nine times the emissions. Timber is a low-carbon material: it is a natural product, needs minimal processing and refinement to make into a usable building material, and can lock up carbon in the building through ‘carbon sequestration’ – which is why it is sometimes thought of as carbon negative. But, even if this last aspect is not accounted for, timber still has significantly lower embodied carbon than alternative building materials, such as concrete, steel, brick or blockwork.
STRUCTURALTIMBERMAGAZINE.CO.UK
At Architype we have developed a detailing strategy using timber to ensure that building designs achieve the highest thermal performance on education projects. The system uses deep timber I-joists or Larsen trusses on the outside of the timber frame or cross laminated timber (CLT) structure, which can then be filled with cellulose (recycled newspaper) to form an envelope with no thermal bridges and minimal temperature loss/ gain through the envelope. These requirements reduce heating demand by 90% compared to typical newbuild schools and help to meet the Passivhaus standard, which ultimately aims to minimise operational energy. Timber also has many other environmental benefits besides lowering carbon. The research into biophilia has shown that being surrounded by nature can benefit health and wellbeing. It can provide great aesthetics and being surrounded by the beauty of nature and natural materials puts us at ease, lowering stress levels and other wellbeing indictors. This is essential in educational buildings,
