BCAB #1845

May 1, 2020

Re: Spatial Separation Calculations for Houses

Project Description

The projects are side by side attached residential townhouses designed under Part 9 of the BC Building Code. There are no dwelling units above another dwelling unit. On the first storey, each townhouse dwelling unit incorporates a storage garage. The storage garages have opaque, (no glazing) overhead garage doors to accommodate vehicular access to the garage.

Applicable Code Requirements

There is agreement between parties involved that Sentence 9.10.15.4.(1) of Division B of the British Columbia Building Code 2018 is applicable.

9.10.15.4. Glazed Openings in Exposing Building Face

1) Except as provided in Sentence (6), the maximum aggregate area of glazed openings in an exposing building face shall

a) conform to Table 9.10.15.4.,

b) conform to Subsection 3.2.3., or

c) where the limiting distance is not less than 1.2 m, be equal to or less than the limiting       distance squared.

Decision being Appealed (Local Authority’s Position)

The local authority has determined that the opaque (unglazed) overhead garage door(s) must be taken into account in the calculations for spatial separation requirements as they are unprotected openings.

Appellant's Position

The appellant has chosen to apply Clause 9.10.15.4.(1)(a), and maintains that only glazed openings are applicable for spatial separation in these building’s as designed and that the subject opaque (no glazing) overhead garage doors need not be considered.

Appeal Board Decision #1845

It is the determination of the Board that the opaque (no glazing) overhead garage doors need not be considered in the spatial separation for these buildings when considering the application of Sentence 9.10.15.4.(1).

Reason for Decision

• Subsection 9.10.15. makes no direct reference to the defined term of unprotected openings, and only references glazed openings.
• The Board takes further guidance from the NBC 2015 Part 9 User's Guide, indicating:

9.10.15.4. Glazed Openings in Exposing Building Face

“Maximum Permitted Aggregate Area of Glazed Openings: The limits that are placed on the openings in exposing building faces of houses apply only to glazed openings such as windows, sliding doors and hinged doors with glazing. The area of glazed opening is measured to the rough opening of the window or door, not just to the edge of the glazing.

The maximum permitted aggregate area of glazed openings can be determined using NBC Table 9.10.15.4., NBC Subsection 3.2.3., or by calculating the area that is equal to or less than the limiting distance squared, where the limiting distance is not less than 1.2 m (3 ft. 11 in.) Where the tables in Part 3 are used, the limits for unprotected openings apply to glazed openings.”

Lyle Kuhnert

Chair, Building Code Appeal Board