9.8.4.1.

(1) Except as provided in Sentence (2), risers shall have uniform height in any one flight with a maximum tolerance of,

(a) 6 mm between adjacent treads or landings, and

(b) 6 mm between the tallest and shortest risers in a flight.

(2) Except for required exit stairs, where the top or bottom riser in a stair adjoins a sloping finished walking surface such as a garage floor, driveway or sidewalk, the height of the riser across the stair shall vary by not more than 1 in 12.

(3) Treads shall have uniform run and tread depth, with a maximum tolerance of,

(a) 6 mm between adjacent treads, and

(b) 6 mm between the deepest and shallowest runs and treads in a flight.

(4) Where angled treads or winders are incorporated into a stair, the treads in all sets of angled treads or winders within a flight shall turn in the same direction.

(5) Cross-slope of treads shall not exceed 1 in 100.