BCAB #1490 - Tapered and Straight Treads in Same Stair, Sentences 188.8.131.52.(1), 184.108.40.206.(1) & 220.127.116.11.(1)
August 17, 1999
Re: Tapered and Straight Treads in Same Stair, Sentences 18.104.22.168.(1), 22.214.171.124.(1) & 126.96.36.199.(1)
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 188.8.131.52.(1) and have a uniform run at the centre of 259 mm.
Reason for Appeal
Sentence 184.108.40.206.(1) states that "Treads … shall have a uniform … run in any one flight."
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 220.127.116.11.(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