LVL in Surrey

In 2015 the Cranleigh School in Surrey celebrated its 150th anniversary. Cranleigh opened in September 1865 as a school for the sons of local farmers but evolved into a co-educational boarding school, "a thriving community of more than 600 boys and girls," per the school. That same sesquicentennial year Allies and Morrison were hired to redevelop a disused squash court and expand it into new teaching facilities and cafe. The recently completed expansion follows the gable forms of the historic brick buildings on campus but departs from them with its wood facades, which hint at the LVL structure inside.

Jack Stephenson, architect at Allies and Morrison, describes the decision to use wood: "Timber is used extensively in this project and is inherent in its design concept. The structural timber is exposed to view throughout, providing maintenance-free soffits that give character and warmth to the building’s spaces." That warmth is expressed in the finished photography of the spaces beneath the wood gable roofs.

The specific laminated veneer lumber used at Cranleigh is Kerto LVL, an "incredibly strong and dimensionally stable" product that "is produced from 3mm thick, rotary-peeled softwood veneers that are glued together to form a continuous b​illet [then] cut to length and sawn into LVL beams, planks or panels," per Metsä Wood. To achieve longer spans, the architects and engineers opted for Kerto-Ripa, "an enhanced system" that glues Kerto LVL S-beams & Kerto LVL Q-panels to achieve spans up to 20 meters.

According to a case study on the project at Metsä Wood, "Floor panels were constructed using 37mm thick Kerto LVL Q-panels as deck and 73x358mm Kerto LVL S-beams as ribs. The roof panels were constructed with 25 mm Q-panels and 45x300 mm S-beams." 

Visit Metsä Wood's website for additional technical information on the installation of their Kerto LVL product at Cranleigh School.