Using Ungraded Lumber for Construction
Obtaining a building permit under the Ontario Building Code with ungraded lumber specified can be difficult
Ungraded sawn lumber has been used as a construction material in North America since it was first colonized. Timbers, logs, and lumber were a valuable commodity from the settlements of the new world. These materials were used regularly in construction. Following the construction boom after the Second World War, building codes required more controls of the quality of lumber used for light framed construction. This ensured that engineering and construction standards could be maintained to meet safety requirements. After the introduction of building codes, the National Lumber Grading Authority (NLGA) was created in the 1970s to maintain lumber grading rules and standards.
Lumber grading and the requirement to use graded lumber in prescriptive construction is a relatively new code requirement. An issue arises when the general population wants to use locally sourced and ungraded lumber for their construction project. It is not possible to get lumber graded outside of a manufacturing facility due to limitations of NLGA and the availability of certified lumber graders. To the general population they see countless old buildings constructed from locally sourced lumber that was ungraded, but their project cannot proceed in a similar way.
When it comes to the use of ungraded lumber in construction and obtaining a building permit it usually involves multiple parties including the property owner, general contractor, design engineer and chief building official. The main parties involve the design engineer and the chief building official and generally they review the acceptable solutions under the building code at the permitting stage of a project.
Most structural engineers are familiar with the CSA design codes required for wood engineering. The design codes and the building code require the use of graded lumber to adhere to the acceptable solutions provisions of the building code. An engineer knowledgeable in the engineering design of wood and lumber grading can use engineering first principles to meet the objectives and functional statements of the building code. To obtain a permit the engineer can demonstrate building code compliance through performance based structural engineering and alternative solutions. Ultimately, it is up to the CBO to decide on whether the use of ungraded lumber meets building code requirements. This has been achieved by engineers using acceptable solutions and a letter or by using alternative solutions and performance-based design.
The use of ungraded lumber can be used in construction provide an engineer completes a performance-based design and grades the lumber. It can be a challenge to obtain a permit when ungraded lumber is specified as CBOs are unfamiliar with code compliance other than acceptable solutions. The alternative solutions compliance path will require an understanding of the building code objectives and functional statements. An experienced engineer will also be required to prepare performance-based design documentation and general reviews to visually grade the lumber.
For design engineers that want to specify locally sourced and ungraded lumber for construction projects they should prepare the alternative solutions compliance path prior to submitting for permit. This will inform the CBO that other than an acceptable solutions approach will be used by the design engineer to ensure building code compliance. To ensure code compliance is met, the engineer will need to be knowledgeable in engineering design in wood and provide general review and field services to visually grade the lumber.