Staircases near you

Riser height is measured vertically between the leading edges of adjacent treads, and tread depth horizontally between the vertical planes of the foremost projection of adjacent treads. Those definitions matter, because they are why a nosing that projects further on one step than another changes the measured tread depth even though the structure underneath is identical.

The adopted numbers are a state question. Cheney, Washington, publishing the 2021 IRC it enforces, states that stair treads are to be a minimum of 10 inches deep with a maximum riser of 7 3/4 inches and that risers must not vary in height by more than 3/8 inch in a run of stair. Connecticut's published excerpt of the residential code portion of its state building code sets the maximum riser height at 8 1/4 inches and the minimum tread depth at 9 inches, with the same 3/8 inch limits on variation in both riser and tread. A stair legal in Hartford would fail in Cheney. This is not a detail to take from a website; it is a call to your building department.

Connecticut also shows how much remodeling turns on the exceptions a state writes in. Its published text allows a maximum riser height of 9 inches and a minimum tread depth of 8 inches for existing or replacement stairs serving an existing unfinished attic or basement being converted to habitable space, where the pitch cannot be reduced because of existing construction. If you are finishing an attic and the existing stair is steeper than a new one would be allowed to be, that exception may be the difference between a project that works and one that does not. Whether your state adopted anything similar is the first question to ask.

The shape of a stair is chosen by the floor plan more than by taste, and each shape has its own rules. A straight run is the cheapest to build and the most demanding of floor area. An L-shaped or U-shaped stair with a landing breaks the run into two flights and fits a smaller footprint, at the cost of the landing's own floor space.

Winders are the wedge-shaped treads used to turn a stair without a landing, and the code measures them along a walkline. The walkline across winder treads is defined as running concentric to the curved direction of travel and located 12 inches from the side where the treads are narrower. Connecticut's published text requires winder treads to be at least 10 inches deep measured at the walkline and at least 6 inches deep at any point within the clear width of the stair, with the largest winder tread depth at the walkline not exceeding the smallest by more than 3/8 inch. Consistently shaped winders are allowed within the same flight as rectangular treads and do not have to match them within 3/8 inch.

Spiral stairs are treated as a special stairway with their own dimensions. As published in that adopted text, a spiral stairway is permitted provided the minimum width at and below the handrail is 26 inches and the walkline radius is not greater than 24 1/2 inches, each tread is at least 6 3/4 inches deep at the walkline, all treads are identical, the rise is no more than 9 1/2 inches, and a minimum headroom of 6 feet 6 inches is provided. Those numbers are why a spiral fits where nothing else will and why almost nobody enjoys carrying furniture up one.

Three dimensions constrain the space around a stair as much as the treads constrain the stair itself. First, landings: there must be a floor or landing at the top and bottom of each stairway, with one published exception, that a floor or landing is not required at the top of an interior flight, including stairs in an enclosed garage, provided a door does not swing over the stairs.

Second, total rise. A flight of stairs may not have a vertical rise larger than 147 inches between floor levels or landings. In a house with a very tall floor-to-floor dimension, that forces an intermediate landing whether or not the plan wanted one.

Third, headroom. The minimum headroom in all parts of the stairway must be not less than 6 feet 8 inches, measured vertically from the sloped plane adjoining the tread nosing, or from the floor surface of a landing. There are two published exceptions worth knowing: where the nosings of treads at the side of a flight extend under the edge of the floor opening the stair passes through, that opening may project horizontally into the required headroom a maximum of 4 3/4 inches; and in Connecticut's adopted text, existing or replacement stairs serving an existing unfinished attic or basement being converted to habitable space may have 6 feet 4 inches of headroom. The walking surface of treads and landings also has a limit: no steeper than one inch of fall in 48 inches, which is a 2 percent slope.

The stringer is the sloped member that carries everything. Understanding which type you have explains most of what can and cannot be changed later.

New or rebuilt stairs are permitted work in almost every American jurisdiction, because the stair is a structural element and a means of egress at the same time. Expect the inspector to measure risers and treads individually rather than take an average, and expect the geometry to be checked before the finish covers it.

Width is measured in two places and people are often surprised by the second. Stairways must be not less than 36 inches in clear width at all points above the permitted handrail height and below the required headroom height; handrails must not project more than 4.5 inches on either side; and the minimum clear width at and below handrail height, including treads and landings, must be not less than 31.5 inches where a handrail is on one side and 27 inches where handrails are on both sides. Connecticut's published exception for existing or replacement stairs serving an attic or basement being converted to habitable space lowers those to 32 inches, 28 inches and 24 inches respectively, with handrails projecting no more than 4 inches. There is also an allowance of not less than 20 inches of clear passage width where a stairway chairlift or platform lift is installed in a dwelling.

Lighting is a code requirement too, not a design choice. The residential code requires that all stairs be provided with illumination, which in practice means a light that reaches the treads and landings and a switch at each level of a flight. It is the most commonly overlooked item on an otherwise finished stair project.

Stairs are priced by the riser and by the complexity of the geometry, and geometry is what separates two quotes. What moves an American quote is the number of risers, whether the flight is straight or has a landing, winders or a curve, whether it is open on one or both sides, whether the stringers are cut or housed, the species and grade of treads and risers, whether the floor opening has to be reframed, whether headroom or width forces structural work, how much of the existing stair is being reused, whether handrails and guards are in this contract, the finish, and the permit and inspections. Ask for a per-riser figure and a separate line for any structural work.

LokalMatch is only the introduction. You describe the stair once: how many steps, whether it is new or a rebuild, the shape you want, what is above and below it, and the age of the house. Stair builders, carpenters and general contractors covering your area receive the request, and the ones interested contact you directly. Pros pay for the requests they receive, which is how it is funded, and homeowners use it free. LokalMatch does not build stairs, does not set or suggest prices, and does not vet, rank or recommend the contractors who respond, so verifying licensing, insurance and the permit plan, and confirming that the adopted code numbers were checked with your building department, stays with you.