The Ontario Building Code | General
11.4.3.1. General
(1) Where the performance level of an existing buildingis reduced under Subsection 11.4.2., compensating constructionshall be carried out in accordance with this Subsection.
(2) Except as provided in Sentence (3), compensating constructionrequired under this Subsection applies to the part of the buildingbeing altered and shall include,
(a) fire separations, with the required fire-resistance ratings, separating the part being altered from the floor areas immediately above and below and from the immediate adjacent areas, and
(b) access to exits and exits from the building, where the alteration adversely affects the exit system of the building.
(3) Compensating construction required under this Subsection applies to the existing building systems that are adversely affected by the proposed construction.
In Plain Language
Where a renovation reduces an existing building's performance level, compensating construction is required, as set out in this article, generally including upgraded fire separations for the altered part of the building, offsetting the reduced safety margin.
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.