Cross Laminated Timber – The Basics

Commonly referred to as ‘CLT’, this type of timber construction is making waves in the property industry for all the right reasons.

From timber.net.au:

CLT is fabricated by bonding together timber boards with structural adhesives to produce a solid timber panel with each layer of the panel alternating between longitudinal and transverse lamellae.

clt house

Couldn’t locate the ultimate source of this, but props to the architect anyway.

There are two attributes of CLT that I find most appealing;

  1. The ability to use small timber dimensions to build up large components, meaning we can more quickly turn over timber plantings and capture more carbon, and
  2. The ability to pre-fabricate entire building components up to some significant dimensions.

There are a range of advantages with CLT that are making it increasingly attractive to mainstream developers, such as;

  • Integrated structure and fabric, allowing dematerialisation and significantly faster construction;
  • Off-site pre-fabrication of elements, allowing high quality control, educed site time and minimised wastage [and watch how automated pre-fabrication will evolve with BIM and robots], and increased safety;
  • High thermal and sound insulation – the fibrous nature of timber combined with the cross lamination contribute to good insulation values;
  • Good fire resistance – contrary to intuition solid timber performs well in fire; once it’s charred it takes some time to burn, doesn’t deform in heat and often retains structural integrity after a fire;
  • Sustainably sourced timber and carbon sequestration.
olpererhutte_mkp-bauingenieure6

Hermann Kaufmann’s Olpererhütte in the Austrian Alps. Remote sites helped stimulate the development of CLT technology in Austria. Nice view.

A good site to visit is Lend Lease’s CLT site [and I’m not plugging them – it’s just credit where credit is due], which provides an overview of CLT, additional benefits from a developer-builder’s perspective, and some good links to more sites related to CLT.

forte herald

Lend Lease’s Forte apartments, tallest timber living in the world. .

I’m curious now as to the uptake of CLT in residential construction. Maybe the greatest challenge is for us to make timber homes more desirable than brick veneer – arguably the worst possible construction choice for the Australian climate.

Keep an eye on this CLT construction: given its high carbon sequestration and displacement of other high-emissions materials such as concrete and steel, it might be the surest pathway to zero carbon buildings.

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