The Ontario Building Code | Machine Stress Rated Lumber
9.3.2.3. Machine Stress Rated Lumber
(1) Machine stress rated lumber shall conform to the requirements of Subsection 4.3.1.
In Plain Language
Machine stress rated (MSR) lumber, graded by a mechanical process rather than visual inspection, must meet the requirements set out in this article.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.