In addition, manufacturing wood products, such as glulam and CLT, requires significantly less energy than producing other building materials. Together with responsible logging and regrowth in forests, building with timber allows for the maintenance of a healthy atmosphere and planet.
Architectural Expression
Building with visually exposed timber allows for the creation of beautiful, unique interior and exterior designs that truly make a statement. Timber offers a built-in richness and elegance that can elevate any building project, creating a pleasing and attractive environment for occupants. Light weight wood's low density and high strength-to-weight ratio results in timber structures that weigh significantly less than their steel and concrete counterparts. These weight savings are particularly advantageous on sites with poor soils and in locations with high seismic loads (which are proportional to mass).
Timber is also a natural choice for the construction of additional floors to existing buildings, minimizing the need to reinforce foundations.
Construction
Building with timber offers the advantage of speed during construction. Since panelized and modular timber elements are manufactured off-site, a mass timber building can be constructed up to 20%-30% faster than a steel building or cast-in-place concrete building and with a much smaller crew of workers on site.
Waste management is also simplified with timber, both in the manufacturing process and on-site, due to the level of prefabrication, eliminating the need to cut elements on-site. For this same reason, construction sites are quieter and safer than when building with traditional materials.
What Are the Challenges?
Construction
Construction costs depend greatly on project requirements. Mass timber buildings are often cost-competitive when all factors, including construction time, are considered. Early coordination is also necessary when working with prefabricated timber elements. For example, locations and sizes of openings for mechanical and electrical services must be fully detailed in advance.
All Entuitive projects are prepared using a BIM platform, allowing close coordination with other disciplines before releasing construction documents.
Supply Chain & Pricing
As products are not yet standardized in the mass timber industry, early engagement of the timber trade in the design process is preferred. Entuitive’s specialists can assist with the assessment and selection of a timber supplier.
Approvals
North American codes typically allow a height of up to six storeys for mass timber buildings. However, Entuitive can assist with the alternate approvals process for taller structures. The 2021 International Building Code will allow certain mass timber buildings up to 18 storeys.
Insurance
The cost of insurance during timber construction is generally higher than construction with traditional materials. Engaging insurers early in the process to help accurately assess risks, particularly for mass timber structures that are less prone to construction fires than light wood frame buildings, can help control insurance costs.
Acoustics & Vibration
Timber structures are lighter and more prone to vibrations and the transmission of airborne and impact sounds. As such, careful design for the control of vibrations and appropriate acoustic isolation measures are required for timber projects.
Fire
Mass timber behaves very differently than light wood frame buildings when exposed to fire. Large timber elements develop a char layer that insulates the wood beneath. Mass timber elements can therefore be engineered to achieve fire-resistance ratings by accounting for this char layer during design, allowing the timber to be left exposed. These elements can also be encapsulated in drywall or a similar material to achieve the required fire-resistance rating if the exposed timber aesthetic is not critical to the project.
Entuitive offers specialized, performance-based fire engineering services that explore advanced engineering solutions for our clients, including pedestrian and evacuation modelling. We take a holistic approach, applying fire modelling, structural fire engineering, and evacuation modelling to demonstrate the performance of timber buildings to clients and building officials.
Moisture
Wood is a natural material that absorbs and releases moisture with changes in the environment. Effective weather protection during construction, when the variation in moisture content is most severe, ensures that dimensional changes do not exceed allowable tolerances, and that finishes, such as roofing membranes, can be properly installed.