BCAB #1936 - Required Width of Stair Below Handrails

September 10, 2024

Re:  Required Width of Stair Below Handrails

Project Description

The project is the construction of a second storey addition to an existing single-family residence.

A new, single flight stair has been constructed to connect the floor area of the addition to the existing main floor.  The width of the stair above the handrail (i.e., at shoulder height) measured between finished wall surfaces, is 890 mm.

The handrail projects into the width of the stair such that the stair width between the wall and the handrail is 800 mm.

Inset wall construction below the handrail also projects into the width of the stair such that the stair width below the handrail, between walls, (i.e., at waist height and below) is also 800 mm.

The general configuration of the stair is as illustrated below:

Applicable Code requirements (BCBC 2018)

Sentence 9.8.2.1.(4), Division B, Stair Width

(4) At least one stair between each floor level within a dwelling unit, and exterior stairs serving a single dwelling unit except required exit stairs, shall have a width of not less than 860 mm.

Sentence 9.8.7.6.(1), Division B, Projections into Stairs and Ramps

(1) Handrails and constructions below handrails, including handrail supports and stair stringers, shall not project more than 100 mm into the required width of a stair or ramp.  (See Articles 9.8.2.1. and 9.8.5.2.)

Decision being appealed (Local Authority’s position)

The lower portion of the wall, located below the handrail, which is a contiguous, integral, and structural element of the building is not considered to be a projection.  The Code permission to project 100 mm into the required width of the stair does not apply to the wall construction below the handrail.

Appellant's position

The width of the stair below the handrail is permitted to be 760 mm.  BC Building Code Interpretation Committee, File No: 98-0098, interprets similar language found in Part 3 of the 1998 BC Building Code.

The inset wall below the handrail, at the top of which is the narrow shelf upon which the handrail is mounted, is a “handrail support”.

The constructed width of the stair below the handrail is 800 mm and complies with the Code.

Appeal Board Decision #1936

The Board reverses the decision of the local authority.

The required width of the stair is 860 mm.

The handrail and the inset wall below the handrail are considered to be “handrails and constructions below handrails” and are permitted to project not more than 100 mm into the required width of the stair.

The general configuration of this interpretation is as illustrated below:

Reason for decision

The head note for Article 9.8.7.6., Division B, includes the word “projections”.  However, the BC Interpretation Act [1] stipulates that a head note “is not part of an enactment” (i.e., not part of the Code) and “must be considered to have been added editorially for convenience or reference only”.

For that reason, the question should not be “is the inset wall a ‘projection’ ”?  Rather, the question becomes “is the inset wall ‘constructions below handrails’ ”?  The Board concludes that it is.

Certain elements may project into the required width of the stair.  The Board interprets that when a stair is wider than the required width, the projection of elements is measured from vertical planes representing the required width, not from the actual width.

The Board notes that File No: 98-0098, prepared by the BC Building Code Interpretation Committee and referenced by the Appellant, interprets Part 3 of the 1998 Code rather than Part 9 as applies in this case.  The Part 3 wording in that edition of the Code included the “on each side” wording that was subsequently removed in the 2018 edition of the Code.

Don Pedde
Chair, Building Code Appeal Board