BCAB #1913

September 28, 2023

Re:  Building Height – Change of Occupancy

Project Description

The project is the change of use of an existing building.  The existing building was originally constructed in the 1970’s and is currently changing from a Group B occupancy to a Group A, Division 2 occupancy.

The building is of wood frame construction, is unsprinklered, and has a building area of approximately 411m².  The building is situated on a sloping site.  At one end of the building three storeys are visible.  The ground slopes up such that only two storeys are visible at the opposite end.  The lowest storey is partially in the ground.

Applicable Code requirements (BCBC 2018)

Sentence 1.4.1.2.(1), Division A, Defined Terms
Grade means the lowest of the average levels of finished ground adjoining each exterior wall of a building, except that localized depressions need not be considered in the determination of average levels of finished ground.
(See First storey and Note A-1.4.1.2.(1).)
First storey means the uppermost storey having its floor level not more than 2 m above grade.

Decision being appealed (Local Authority’s position)

The average level of the finished ground at the single exterior wall located lowest on the sloping site is grade for the purpose of determining the first storey and the building height.  Grade is approximately 2.4m below the floor level of the next storey above.  Therefore, the partially in-ground lowest storey is the first storey and the building is three storeys in building height.

Appellant's position

Grade is a calculation of average levels of finished ground at the perimeter of the partial bottom floor.  On that basis, grade is calculated to be 1.98m below the floor level of the next storey above.  The next storey above is the first storey and the building is two storeys in building height.

Appeal Board Decision #1913

The Board confirms the decision of the Local Authority.  It is the determination of the Board that based on the definitions of first storey and grade the building is three storeys in building height.  The Board acknowledges that building height is only one of the aspects to consider when determining the appropriate level of safety in a building undergoing a change of occupancy.

Reason for decision

The definition of grade stipulates that each exterior wall, rather than the average of multiple exterior walls, is used to establish grade.

Consideration of Sentence 1.1.1.2.(1), Division A, and Note A-1.1.1.2.(1), Division A, Application to Existing Buildings, is advisable and the “User’s Guide - NBC 1995, Fire Protection, Occupant Safety and Accessibility (Part 3)” provides a method for evaluating existing buildings.

Applicable Code requirements (BCBC 2018)

Article 1.1.1.1., Division A, Application of this Code
1) This Code applies to any one or more of the following:
a) the design and construction of a new building,
b) the occupancy of any building,
c) a change in occupancy of any building, . . .

Article 1.1.1.2., Division A, Application to Existing Buildings
1) Where a building is altered, rehabilitated, renovated or repaired, or there is a change in occupancy, the level of life safety and building performance shall not be decreased below a level that already exists. (See Note A-1.1.1.2.(1).)

Note A-1.1.1.2.(1), Division A, Application to Existing Buildings.
This Code is most often applied to existing or relocated buildings when an owner wishes to rehabilitate a building, change its use, or build an addition . . .

The successful application of Code requirements to existing construction becomes a matter of balancing the cost of implementing a requirement with the relative importance of that requirement to the overall Code objectives. The degree to which any particular requirement can be relaxed without affecting the intended level of safety of the Code requires considerable judgment on the part of both the designer and the authority having jurisdiction.

Don Pedde
Chair, Building Code Appeal Board