Sustainable school building made of wood

Kerto-Ripa Floor and Roof Elements

The three-storey building has a grid of 2.20 x 6.60 meters. The roof and floor elements of the building are so-called Kerto-Ripa Box elements, where Kerto LVL S-beams act as ribs and the upper and lower panels are made of Kerto LVL Q-panels. The longest floor span is 6.5 meters and depending on the span, upper and lower panels have a thickness of 27 or 39mm, with supporting ribs of 45/69x300mm. The floor elements are equipped with 100mm Knauf Naturoll 0.32 insulation. The roof and the first-floor structure meet a 30-minute fire resistance requirement, while the second floor has a 60-minute rating.

De Groot Vroomshoop suggested using to Kerto wooden box elements to eliminate shear forces from the floor elements, considering cost implications.

The architect specifically wanted to leave the structure visible. As a result, the wooden post and beam structure, the undersides of the Kerto LVL floor elements and the steel corner brackets used to support the elements have been left exposed. De Groot Vroomshoop has engineered, prefabricated, and assembled the entire wooden supporting structure, including the wooden floor and roof elements. They have been involved in this project from the design stage.

Auditorium Tribune

The seating area in the auditorium, a total of 100m², is also constructed using Kerto LVL. The steps are made of 39mm thick Kerto LVL Q panels, and the substructure is built with Kerto LVL S-beams. Gerko from Harlingen engineered the stands, fully (CNC) prefabricated them, and also took care of the installation. Due to the high level of prefabrication and extensive experience, the strong structure was realized with minimized construction time.  

Sustainability

Sustainability and circularity were fundamental considerations throughout the design and construction phases. All building materials are designed to be easily disassembled and reused in the future, documented using Madaster's material passport. The building's heating and cooling are provided by a Ground Source Heat Pump (GSHP) system designed and installed by Spie. The presence of 9.000 solar panels on the roofs generates electricity, making eco-conscious choices. By incorporating Kerto-Ripa elements into this hybrid wooden construction, a highly material-efficient wood product with a remarkably low CO₂ footprint was used. About 165 m³ of Kerto LVL and 110 m³ of laminated spruce wood were utilized, storing precisely 200 tons of CO₂, according to Metsä Wood's Carbon Storage Calculator. Kerto LVL, a premium laminated veneer lumber, is 2.5 times stronger than standard lumber, 1.5 times stronger than structural plywood, highly durable, rigid, lightweight, and PEFC certified, used in various construction applications. 

Kerto-Ripa elements are structurally bonded floor and roof elements based on Kerto LVL, manufactured under controlled conditions, enabling structural calculations for distributing forces within the element.