French beech – a new opportunity in wood housing

Abstract

Hardwood housing especially from beech is one item of possible added value products based on solid wood and / or wood reconstituted in Europe. However, design of structures requires structural product with a certified strength according to regulatory framework of CE marking. French beech forest occupies about 1.4 Mha lead mainly in regular high forests and coppices with standards with an annual volume of harvested wood (1 million m3) for a sawn timber estimated at 400000 m3. FCBA has launched since in 2011 a study to characterize the French beech as a raw material and its structural bonding. To qualify French beech species as solid wood, a national representative sampling was performed to collect 2400 lumbers (6 French areas, 21 stands, 99 trees, 3 cross-sections) and to establish visual grading rule (NF B 52 001-1 2017) for assessment in D40-D24 or D35-D18. A new table of strength classes of European hardwood (EN 338) will be proposed according to experimental results. Grading machine could be done for D50 with a good yield (38-47%). A general work plan has been developed to reach requirements for beech glulam in two steps. Firstly, the compatibility of different type I adhesives technology was studied by the way of lab tests usually performed in the field of common adhesives approval (EN 302-2). On the other hand, full scale tests according to EN 14080 have been done to characterize glulam beams (58 beams - GL32h) with verification of finger joint performance. French beech data could be merged with other hardwood data to develop a GLT CE marking standard as EN 14080 part 2 specifically devoted to hardwoods. The construction market in the future could provide an important alternative for French beech, particularly in the form of reconstituted products.