The Ontario Building Code | Top Plates
9.23.11.3. Top Plates
(1) Except as permitted in Sentences (2) to (4), no fewer than two top plates shall be provided in loadbearing walls.
(2) A single top plate is permitted to be used in a section of a loadbearing wall containing a lintel provided the top plate forms a tie across the lintel.
(3) A single top plate is permitted to be used in loadbearingwalls where the concentrated loads from ceilings, floors and roofs are not more than 50 mm to one side of the supporting studs and in all non-loadbearing walls.
(4) The top plates need not be provided in a section of loadbearingwall containing a lintel provided the lintel is tied to the adjacent wall section with,
(a) not less than 75 mm by 150 mm by 0.91 mm thick galvanized steel, or
(b) 19 mm by 89 mm by 300 mm wood splice nailed to each wall section with at least three 63 mm nails.
In Plain Language
Top plates must meet the specific requirements set out in this article, addressing this member's role connecting stud tops and supporting the structure above.
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.