Fire Performance Ratings

BRANCH OPINION

Article 9.23.7.2.
Levelling of sill plate and gaskets

ISSUE: Acceptance of a gasket plate between the top of the foundation wall and the sill plate.

In the 1997 Ontario Building Code (OBC), changes were made to the written requirements in Article 9.23.7.2. Levelling of Sill Plates. These changes did not make reference to "an acceptable gasket plate" as an option that was permitted in the previous code. The 1990 OBC permitted the junction between the foundation and the sill plate to be sealed with "an acceptable gasket plate" before being compressed as one of the options. Although the gasket plate is not referred to in the 1997 OBC, it is the opinion of the Housing Development and Buildings Branch that it would be acceptable as an alternative to a layer of mineral wool not less than 25 mm (1 in) thick.

1990 Ontario Building Code Requirements: ⁽¹⁾

Article 9.23.7.2. Levelling of Sill Plates

Except as permitted in Sentence (2) sill plates shall be levelled by setting them on a full bed of mortar.
Where the top of the foundation is level, sill plates referred to in Sentence (1) may be laid directly on the foundation provided the junction between the foundation and the sill plate is caulked or sealed with an acceptable gasket or a layer of mineral wool not less than 25 mm (1 in) thick before being compressed.

1997 Ontario Building Code Requirements ⁽¹⁾
Article 9.23.7.2. Levelling of Sill Plates

Sill plates shall be levelled by setting them on a full bed of mortar, except that where the top of the foundation is level, they may be laid directly on the foundation provided the junction between the foundation and the sill plate is caulked or the sill plate is placed on a layer of mineral wool not less than 25 mm thick before being compressed.

⁽¹⁾ This information is provided for convenience only. For accurate reference, recourse should be had to the official volumes(Regulations).

Under the Ontario Building Code Act, the local Municipality is the authority having jurisdiction and they are responsible for enforcing the Ontario Building Code Act and its regulations.

Ali Arlani, P.Eng. April 20, 2001
Manager - Code Development and Training Section

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