BCAB 1982 - Alternative solution for the alteration of an existing house to add a second dwelling unit

Alternative solution for the alteration of an existing house to add a second dwelling unit

Project Description

The project is the design of a renovation and addition to an existing four-storey, single-family dwelling to add a second dwelling unit.  The building permit for the existing house was issued in 1980.

The existing house is located on a steeply sloping site and has four floor levels, stepping up the hillside.  The top three levels contain residential living areas and the bottom level contains a partially covered parking area.  The house is not sprinklered.  It is proposed that the parking level be renovated, extended, and converted into a second dwelling unit.

An alternative solution is proposed to address the number of storeys in building height and the inclusion of the second dwelling unit.

Applicable Code requirements (BCBC 2024)

Sentence 1.1.1.2.(1), 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).)

Sentence 1.2.1.1.(1), Division A, Compliance with this Code

(1) Compliance with this Code shall be achieved by

(a) complying with the applicable acceptable solutions in Division B (see Note A-1.2.1.1.(1)(a)), or

(b) except as required by Sentence (3), using alternative solutions, accepted by the authority having jurisdiction under Section 2.3 of Division C, that will achieve at least the minimum level of performance required by Division B in the areas defined by the objectives and functional statements attributed to the applicable acceptable solutions (see Note A-1.2.1.1.(1)(b)).

Sentence 1.4.1.2.(1), Division A, Defined Terms

Building height (in storeys) means the number of storeys contained between the roof and the floor of the first storey.

Decision being appealed (Local Authority’s position)

The existing building is three storeys plus carport below.  Adding a fourth storey containing a second residential suite decreases the level of life safety below that which already exists.

A four-storey residential building requires sprinklers throughout and the mitigating features in the proposed alternative solution do not provide an equivalent level of safety.  Also, the alternative solution does not address an exit exposure issue.

Appellant's position

Alteration and extension of the parking level does not add a fourth storey to an existing three-storey building.  Rather, the existing parking level is, by definition, the first storey and the existing building is four storeys in building height.

The alternative solution provides analysis to demonstrate that the addition of a secondary suite to this existing four-storey single family dwelling will not reduce the level of fire and life safety of the building.

The measures proposed in the alternative solution will more than offset the risk inherent in the addition of a second dwelling unit.  The alternative solution will achieve at least the minimum level of performance inherent to an existing Part 9 single family dwelling with a new secondary suite.

Appeal Board Decision #1982

The Board varies the decision of the local authority.

It is the determination of the Board that the measures proposed in the alternative solution proposal can be accepted provided that any exit exposure condition is addressed to the satisfaction of the local authority. 

Reason for decision

The Board notes that when the building was constructed in 1980 the Code’s method of determining grade, and the resulting determination of the first storey and the building height, was different than the determination of grade in the current Code.  The current BC Fire Code 2024 makes note of the change, stating, in part, that “The National Building Code of Canada 1990 introduced changes to the method of determining building height.”

Under the current Code and its method of determining average grade, the building is four storeys in building height and the conversion of the lowest level from parking to residential use does not change the building height.

The inclusion of a second dwelling unit increases the fire and life safety risk in the building and the mitigating features in the alternative solution address these risks.

Don Pedde
Chair, Building Code Appeal Board

Dated:  September 18, 2025