Today’s timber construction does not simply work with “wood”, but with engineered timber products. They are made from wood industrially, by grading, drying, finger-jointing and gluing. The result is stronger, more uniform and more dimensionally stable than ordinary sawn timber – these products have made today’s multi-storey timber buildings possible. Below we give an overview of the most important ones; each has its own page with its build-up, technical data, common sizes and uses.
Why are engineered timber products better?
- More uniform. The natural irregularities of timber are evened out, so their strength can be specified more precisely and the design is more reliable.
- More dimensionally stable. Dried and glued, they swell and shrink less than solid timber.
- Larger and stronger. Finger-jointing and gluing allow longer elements, larger spans and higher load-bearing capacity.
- Certified quality. In the EU, only products with proven fitness for use may be installed: their properties are set out in European product standards or European Technical Assessments (ETA).
What all timber products have in common
- Good thermal insulators. The thermal conductivity of softwoods is 0.13 W/mK – that of brick is 0.44, of concrete 1.8.
- Predictable in fire. Timber and most wood-based materials have reaction-to-fire class D-s2, d0; the fire resistance of the load-bearing structure can be calculated from the charring rate.
- They store carbon. One cubic metre of softwood stores about 215–222 kg of carbon – equivalent to about 800 kg of carbon dioxide.