Mass Engineered Timber (MET) is a building material comprising engineered wood products with improved structural integrity. This includes:
- Cross Laminated Timber (CLT)– Layers of wood are stacked cross-wise and bonded with structural adhesives. It is predominantly used for walls, floors and roofs.
- Glued Laminated Timber (Glulam)– Produced in a similar fashion but with the grain aligned in the same direction. It is predominantly used for columns, beams and truss elements.
Why use MET
- Improved productivity– As MET is prefabricated offsite, it can achieve up to 35% in time savings at the project level.
- Better construction environment– Less dust and noise as most work is completed offsite.
- Improved quality control– Highly precise and automated manufacturing processes results in high quality finishing.
- Environmental sustainability– MET is harvested from sustainably managed forests, and MET buildings have lower carbon footprint and net carbon emissions compared to steel or concrete buildings
What to consider when using MET
- Early contractor involvement– Developers/project managers should engage the MET specialist and main contractor during the design stage of the project. This way, the specialist can communicate his recommendations to the main contractor before actual construction begins.
- Site/project management– Time and manpower savings can be gained from good site and project management. This includes adopting best practices for shipping, transportation, delivery, storage, protection, lifting and handling, and site installation.
- Maintenance, replacement and refurbishment– Regular maintenance checks are required for all buildings during their operational lifespan. For MET buildings, building owners should engage a Professional Engineer (PE) to check on areas such as moisture content, end grain, insect and fungi attack, UV treatment, corrosion, significant cracks, delamination and warpage, and deflection (for long span structures of more than 20m). For any replacement or renovation works, a Qualified Person should be consulted prior to commencement.
Compliance to regulations and acceptable solutions in Singapore
- Building Control Regulations 2003– All buildings and structures must comply with the objectives and performance requirements set out in the Fifth Schedule of the Building Control Regulations 2003. The prescribed objectives and requirements are deemed to be satisfied if the design and construction of a building complies with the acceptable solutions set out in the prevailing Approved Document issued by the Commissioner of Building Control.
- Eurocode SS EN 1995 (2018)– For timber structures, the acceptable solution would be in compliance with SS EN 1995 (2018) read with the relevant Singapore National Annexes. Timber structures must also comply with all requirements applicable to the construction of buildings.
- SCDF fire safety requirements– Timber buildings (similar to reinforced concrete or steel buildings) are to comply with the fire safety requirements stipulated by SCDF.
Figure 1: Types of Mass Engineered Timber