Rise of Mass Timber Building in BC Prompts Need for Guidelines

Engineers and Geoscientists BC and the Architectural Institute of British Columbia (AIBC) have published new guidelines to clarify the expectations for professional practice for architects and engineers designing mass timber buildings up to 12 stories. 

The Joint Professional Practice Guidelines - Encapsulated Mass Timber Construction up to 12 Storeys cover minimum qualifications, professional practice, roles and responsibilities, and quality assurance for encapsulated mass timber construction projects. 

The BC government recently implemented changes to the BC Building and Fire Codes to allow construction of mass timber buildings up to 12 storeys ahead of other jurisdictions as a result of the growth in innovative wood engineering and architecture that has recently seen a rise in the province. To support further growth, and to ensure the safe design and construction of taller mass timber buildings, the guidelines were developed to help firms with less experience to benefit from having a basic understanding and best practices of mass timber construction in order to avoid some of the pitfalls of this relatively new way of constructing buildings.

While the building code covers the requirements, the guidelines are a means to supplement the code with more practical considerations. The guidelines identify issues to be taken into consideration, provide sources of information, and even give design options when providing architectural, building enclosure, fire protection, acoustical, structural, mechanical, and electrical design services. 

The guidelines are a result of great discussions and collaborations among professionals and engineers from a variety of disciplines and background. 

Timber Construction Poses Unique Challenges to Building Noise & Acoustics

RWDI's acoustics team provided the acoustical and noise mediation section in the guidelines.  Sound interacts with nearly every building component in some way. For mass timber construction, it is even more important to consider acoustic requirements in the early stages of design, because Mass Timber does not perform well acoustically due to its low density and stiffness. The main acoustical challenges in ecapsulated mass timber construction (EMTC) arise when the mass timber is used as a finish material (i.e. exposed wood).

Exposed wood may lead to several acoustical issues. Wood is a hard, sound-reflective surface, and when exposed as a ceiling in a commercial building will result in reverberant, noisy spaces that are not suitable for office use, due to poor speech privacy and intelligibility.  

The acoustical considerations covered in the guidelines help mitigate common issues and noise risks with timber buildings including: room acoustics, sound isolation, impact/footfall sound insulation, building services noise and vibration control, floor vibration, and exterior to interior noise control.