Our Timber Engineering Division specialises in hybrid structures, often combining the use of green (freshly felled) timber, engineered panel systems, glue laminated members and steel connections. Green timber has a lower embodied energy than glue laminated beams so where appropriate we promote its use. The Douglas fir frame at Loch Lomond is a cutting edge timber structure combining post and beam construction with pre-fabricated floor and roof panels and a site built skin. Because of the large open plan spaces this highly engineered hybrid structure needed to take loadings way beyond the norm.
Post and beam structures readily withstand dead loading (i.e. the weight of the structure itself) but they require bracing to resist imposed loading such as the force of wind. However the architect was keen to avoid the use of diagonal bracing found in most post and beam buildings. Initially consultant engineers tried to use a conventional studded wall system but this proved impractical because of the high forces.
Carpenter Oak & Woodland in collaboration with a number of specialist companies, developed a solution, unique in the UK, using pre-fabricated wall panels with a central vertical ply sheet with top and bottom flanges (essentially a very tall I beam) with vertical ribs at regular intervals to provide rigidity. A final diaphragm skin was applied on site. These panels were used intermittently down the length of the building and across it to provide ‘buttressing’.
Further bracing was achieved with the unique floor beams which comprised of two vertical panels with top and bottom flanges creating an I box section rather than the conventional I beam.
The HQ is the largest ‘green’ timber building in the UK. It uses the largest sections of green timber in the UK with the biggest posts measuring a massive 650mm x 600mm x 6.2m long. Timber is the only sustainable material available for use as a structural space frame for a building
The frame comprises 160 cubic metres of timber weighing in at 80 tonnes. All the timber was sourced from Scotland and the borders. It took 3000 man hours to fabricate in our Angus yard and 3300 to erect on site.