BCAB #1490 - Tapered and Straight Treads in Same Stair, Sentences 9.8.2.1.(1), 9.8.3.1.(1) & 9.8.5.2.(1)

August 17, 1999

BCAB #1490

Re: Tapered and Straight Treads in Same Stair, Sentences 9.8.2.1.(1), 9.8.3.1.(1) & 9.8.5.2.(1)

Project Description

The interior residential stair in question contains a combination of standard (straight) and tapered treads in one flight. The first three treads are straight with a uniform run of 229 mm. The remaining treads are tapered, comply with Sentence 9.8.5.2.(1) and have a uniform run at the centre of 259 mm.

Reason for Appeal

Sentence 9.8.2.1.(1) states that "Treads … shall have a uniform … run in any one flight."

Appellant's Position

The appellant contends that the stair design is safe and as the code does not define where the run is to be measured in a flight the combination of conforming straight and tapered treads should be permitted.

Building Official's Position

The building official wishes the Board to clarify the application of Sentence 9.8.2.1.(1) to a stair containing both straight and tapered treads. Is it the intent to prohibit such a stair?

Appeal Board Decision #1490

It is the determination of the Board that the run must be uniform for all treads in a flight and this can only occur if all treads are identical in shape. Therefore, tapered and straight treads cannot be combined in a flight of stairs without an intervening landing.

George R. Humphrey, Chair