Staircase Sanding & Polishing

A staircase is quoted per tread rather than per square metre because it is not a floor, and pricing it as one badly misrepresents the work. A fifteen-tread flight might have four or five square metres of horizontal surface, and it will take most of a working day to sand properly. Almost none of that time is machine time. It is hand work, scraping and detail sanding, on surfaces that no floor machine can reach.

The tread itself is the easiest part. Risers — the vertical faces — are worked by hand or with a small detail sander, and the internal corner where the riser meets the tread behind it has to be scraped because nothing rotating fits into it. The bullnose, the rounded front edge of the tread, is the hardest single element to get right: it has to keep its profile, which means it cannot be sanded flat, and it takes the most wear of any surface in the house.

Stringers, the raked boards running up each side of the flight, are a separate exercise again. On an open-sided staircase the outer stringer is visible from below as well as above and needs finishing on both faces. On a closed string the joint where the tread meets the wall string is another hand-scraped internal corner. Add balusters, newel posts and a handrail and the surface area that needs attention is many times the horizontal figure.

Wear on a staircase is concentrated in a way it never is on a floor. Every person using the stairs steps in almost exactly the same place on every tread, which produces a worn strip through the centre of each one while the edges remain in original condition. That differential can be several millimetres on an old flight, and levelling it entirely would take the tread below its nosing line. Often the right answer is to reduce it rather than eliminate it.

Structural checks come before any sanding. Treads that flex underfoot, wedges that have worked loose in the housings, or a nosing that has split away are safety matters rather than finish matters, and they get addressed first. A staircase is the one part of a house where a floor finish problem can become an injury, so we are conservative about it and we will decline to simply coat over movement.

Coating a staircase is its own problem because the flight has to stay usable. Coating every tread at once seals off the upper floor for the duration of the cure, which most households cannot accommodate. The standard approach is alternate treads — every second tread coated, allowed to cure, then the remainder — so there is always a usable step. It doubles the coating stage and it is the only practical way to do it in an occupied house.

Slip resistance deserves a deliberate decision rather than a default. A high-gloss finish on a staircase is genuinely less safe than a satin or matte one, particularly in socks on a timber nosing. We recommend satin as a minimum and will discuss an anti-slip additive in the topcoat where there are young children or elderly users in the house. It is a small cost and it changes the risk profile.

Because the work is hand-intensive and the coating is staged, a staircase is quoted per tread at $20 to $35 depending on construction, timber and whether the flight is open or closed. Balusters, newel posts and handrails are quoted separately. We itemise all of it rather than absorbing a staircase into a floor rate, because it is a substantial piece of work that deserves to be visible on the quote.

Matching a staircase to the floor it lands on is worth testing rather than assuming. Stair timber is frequently a different species to the flooring — a Tasmanian Oak floor with a hardwood or even softwood flight is common in Peninsula homes — and the two will not sand to the same tone no matter how carefully the work is done. Where they need to read as one, a stain sampled on both surfaces at the same time is the only reliable way to get there, and it needs deciding before either is coated.