BCAB #1448 - Design of Stair Treads and Landings, Clauses 3.3.1.15.(2)(d) and 3.3.1.15.(12)(d)

November 19, 1997

BCAB #1448

Re: Design of Stair Treads and Landings, Clauses 3.3.1.15.(2)(d) and 3.3.1.15.(12)(d)

Project Description

The stair under appeal is in a single dwelling unit. The front edge of the treads is a convex curve with the centre of the nosing 31/4 inches beyond the ends. The stair turns through 90 degrees and consists of three sets of 3 parallel treads separated by two roughly triangular landings or winders which turn through 45 degrees each.

Reason for Appeal

Clause 3.3.1.15.(2)(d) requires the front edge of treads to be at right angles to the direction of travel. Clause 3.3.1.15.(12)(d) permits landings within a single dwelling unit to comply with Article 9.8.4.1. which states that landings shall be at least as wide and as long as the width of the stair in which they occur but need not exceed 1100 mm in length.

Appellant's Position

The appellant contends the stair design meets the requirements of the code. They have been accepted across Canada and in the U.S. and the curved edge complies with an illustration taken from a guide to the Alberta Building Code.

Building Official's Position

The building official maintains the curved front edge violates the requirement that the front edge of the tread be at right angles to the direction of travel. Appeals #1375, #1214 and # 1063 dealt with this issue and support the interpretation. The landings do not comply with Article 9.8.4.1. and cannot be considered as winders because they do not comply with the minimum run at the narrow end as stipulated in Clause 3.3.1.15.(5)(e).

Appeal Board Decision #1448

It is the determination of the Board that the stair design does not conform to code requirements. The path of travel is at right angles to the front edge of the tread only at the centre of the tread. This is considered an infraction but is not as significant as the design of the landings. The landings do not conform to Article 9.8.4.1. and they cannot be considered as winders because they do not comply with Sentence 3.3.1.15.(5)(e).

George R. Humphrey, Chair