BCAB 1974 - Application of code requirements to the change in occupancy of an existing building

Application of code requirements to the change in occupancy of an existing building

Project Description

The project is the renovation of an existing accessory building on a residential property to change the major occupancy and to convert it into a dwelling unit.

The building is one storey high and about 60 m² in area.  It was designed and constructed under the BCBC 2018 to accommodate eventual conversion to a dwelling unit.  It contains in-floor heating, electrical rough-ins for a cooktop and oven, smoke alarm(s), and finished plumbing for a kitchen and bathroom.

Applicable Code requirements (BCBC 2024)

Sentence 1.1.1.1.(1), Division A, Application of this Code (excerpt)

(1) This Code applies to any one or more of the following:

(c) a change in occupancy of any building,

(d) an alteration of any building,

(i) all parts of any building that are affected by a change in occupancy . . .

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).)

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, or when an enforcement authority decrees that a building or class of buildings be altered for reasons of public safety.  It is not intended that the British Columbia Building Code be used to enforce the retrospective application of new requirements to existing buildings or existing portions of relocated buildings, unless specifically required by local regulations or bylaws.  For example, although the British Columbia Fire Code could be interpreted to require the installation of fire alarm, standpipe and hose, and automatic sprinkler systems in an existing building for which there were no requirements at the time of construction, it is not intended (sic) that the British Columbia Fire Code be applied in this manner to these buildings unless the authority having jurisdiction has determined that there is an inherent threat to occupant safety and has issued an order to eliminate the unsafe condition, or where substantial changes or additions are being made to an existing building or the occupancy has been changed.  (See also Note A-1.1.1.1.(1) of Division A of the British Columbia Fire Code.)

Relocated buildings that have been in use in another location for a number of years can be considered as existing buildings, in part, and the same analytical process can be applied as for existing buildings.  It should be noted, however, that a change in occupancy may affect some requirements (e.g. loads and fire separations) and relocation to an area with different wind, snow or earthquake loads will require the application of current code requirements.  Depending on the construction of the building and the changes in load, structural modifications may be required.  Similarly, parts of a relocated or existing building that are reconstructed, such as foundations and basements, or parts being modified are required to be built to current codes.

Whatever the reason, Code application to existing or relocated buildings requires careful consideration of the level of safety needed for that building.  This consideration involves an analytical process similar to that required to assess alternative design proposals for new construction.  See Clause 1.2.1.1.(1)(b) for information on achieving compliance with the Code using alternative solutions.

In developing Code requirements for new buildings, consideration has been given to the cost they impose on a design in relation to the perceived benefits in terms of safety.  The former is definable; the latter difficult to establish on a quantitative basis.  In applying the Code requirements to an existing building, the benefits derived are the same as in new buildings.  On the other hand, the increased cost of implementing in an existing building a design solution that would normally be intended for a new building may be prohibitive.

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.

Decision being appealed (Local Authority’s position)

The building must be upgraded to comply with BCBC 2024 provisions related to a dwelling unit.  Those requirements are identified as

• increase size of the property’s water service pipe from NPS ¾” to NPS 1” as the property now includes two dwelling units as per Sentence 2.6.3.4.(5), Division B, Book II, Plumbing Systems,
• provide protection from soil gas ingress, as per Sentence 9.13.4.2.(2), Division B, and
• determine required capacity of heating and cooling appliances in accordance with CSA F280 as per Sentence 9.33.5.1.(1), Division B, and provide heating and cooling as per Sentences 9.33.2.1.(1) and (2), Division B.

Appellant's position

The building was constructed under the BCBC 2018 and would have been constructed as a dwelling unit had the local zoning bylaw permitted an accessory dwelling unit on the site.  In anticipation of a zoning change (which has recently occurred), the building was constructed as an accessory building (storage) with provisions to undertake the conversion to a dwelling unit under separate permit when the zoning changed.  The building was constructed with the change of occupancy in mind and no alterations to the existing construction are necessary or proposed.

The Building Code states explicitly that it is not intended that it be used to enforce retrospective application of requirements added in new editions to existing buildings.

A previous appeal decision (BCAB 1857) confirmed that where the Code changes over the course of a project constructed in phases, the edition that applied at the first building permit remains the applicable edition.  On the basis that the building was constructed with provisions for the conversion to a dwelling unit this can be viewed in the same way, as construction of a dwelling unit under two building permits.

Renovations to change occupancy, or major occupancy, are common in existing buildings and Division A of the Code requires that an assessment of whether the building is suitable for the proposed occupancy be made.  On the basis that the building was constructed specifically to accommodate conversion to a dwelling unit, it is suitable for use as a dwelling unit.

That the Code changed between the original construction and the conversion does not preclude the change of occupancy and the Code does not retroactively apply requirements that are in the 2024 edition that were not in the 2018 edition.

Appeal Board Decision #1974

The Board varies the decision of the local authority.

It is the determination of the Board that current Code requirements for protection from soil gas and for heating and cooling provisions apply to this change of occupancy.

The change of occupancy has no bearing on the required private water service pipe size.  The required private water pipe size, as is determined by the cumulative fixture unit load, is the same whether some of the fixtures are located within a storage building (existing) or within a dwelling unit (new).

Reason for decision

Current Code requirements do not apply retroactively to existing buildings unless the building is being modified.  In this case of a change of occupancy, the current Code requirements related to a dwelling unit apply.

However, the change of occupancy is occurring in an existing building.  The degree to which those applicable Code requirements 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.  That judgement could be applied in this case, and the current Code requirements satisfied, to a greater or lesser degree, by means of agreed-upon solutions related to soil gas ingress as well as heating and cooling.

In this case, a building was constructed and occupied, and then modified to accommodate a different use.  This is not considered to be a single phased project regulated by the earliest applicable Code.

Don Pedde
Chair, Building Code Appeal Board

Dated:  July 3, 2025