Stairs and railings, by the same crew that lays the floor.

The rules, with the article numbers

What the Ontario Building Code actually says about a stair.

Rise, run, tread depth, guard height and the gap between spindles are set by Ontario Regulation 332/12, the Building Code, and the numbers are public. They are quoted below with the article they come from, so you can check any quote against the regulation itself. We are flooring installers, not your building department: these are the figures a stair is measured against, not permission to change one.

• Rise and run, for a stair inside a house

  Table 9.8.4.1 of the Code sets private stairs at a maximum rise of 200 mm and a minimum of 125 mm, with a run between 255 mm and 355 mm.[4] The rise is "measured as the vertical nosing-to-nosing distance".[4] At least one stair between floor levels in a dwelling unit must be at least 860 mm wide.[4]

• The 5 mm rule, and why it decides a stair job

  This is the article that matters most when hardwood goes onto an existing staircase. Risers must be of uniform height in a flight, with a maximum tolerance of 5 mm between adjacent treads or landings and 10 mm between the tallest and shortest riser in the flight.[4] Runs carry the same 5 mm tolerance between adjacent treads.[4]

  Cladding treads adds thickness. Add it to every tread and the risers in the middle stay equal, but the top and bottom risers change by whatever the new floor above and below adds. That is exactly where a stair drifts out of the 5 mm tolerance, and it is why the stair gets measured with the floor, not after it. Max's take: this is the single most common thing a cheap stair quote ignores, and you feel it underfoot on the bottom step for the next twenty years.

• Tread depth, which is the nosing

  The Code puts the depth of a rectangular tread at not less than its run and not more than its run plus 25 mm.[4] That 25 mm is the overhang the national flooring guidelines tell installers to check the local code for.[1] A thicker nosing profile than the old one changes that number, which is another reason a tread is not simply a board.

• Guards and spindles

  Guards inside a dwelling unit, other than on a spiral stair, must be at least 900 mm high.[4] Openings through a guard must "prevent the passage of a spherical object having a diameter of 100 mm".[4] That is the number that decides spindle spacing, and it is why iron balusters sit where they do. The Code also requires that no member, attachment or opening between 140 mm and 900 mm above the walking surface will facilitate climbing, which is what rules out a horizontal ladder-style rail.[4] Handrails are set at 865 mm to 1 070 mm high.[4]

• Hamilton names railings as a permit job

  Quoting the Code is not the same as clearing a job. The City of Hamilton's list of projects that require a building permit includes, in its words, "replacement of interior railings/guards", while its list of projects that do not includes "installing minor millwork, cabinetry, and flooring such as carpet, laminate or hardwood".[3] That covers Waterdown, Dundas, Ancaster, Stoney Creek and Binbrook as well as the old city; the Building Division is at 905-546-2720. Burlington, Oakville and Grimsby each publish their own guidance, quoted on the service area pages. Refacing a tread does not change a stair's geometry. Changing a stair or a guard does, and then the answer is the building department's, not ours.