A Step-by-Step for Trimming Stairs
Utility stairs are transformed into a squeak-free finished staircase with straightforward carpentry and easy-to-source parts.
Synopsis: Trim carpenter Gary Striegler details the process of turning a set of builder’s utility stairs into a finished, squeak-free staircase through judicious use of glue and shims.
I think anyone who’s worked on a new multistory construction project would agree that having a set of sturdy, functional stairs makes finishing the build easier. On the houses I work on, the framer builds stairs from stringers and treads cut from 2x12s as soon as possible in order to move material and workers between floors safely and efficiently without risking damage to an expensive finished staircase. When the house gets to the finish carpentry stage, I replace the temporary 2x12s with hardwood treads and cut and fit paint-grade plywood risers and MDF skirtboards to match the site conditions. The enjoyable six- to eight-hour project turns a scuffed and paint-spattered utility stair into an attractive finished staircase.
If you want to save time and avoid redoing work later, it’s important to verify the finished flooring at the top and bottom of the stairs before cutting and installing the 2×12 stringers and temporary treads. You can shim treads and trim stringers to compensate for a change in flooring height from what was planned, but it’s faster and easier to get it right from the start. If miscommunication or a change of mind leads to a different floor thickness, you may need to adjust the stringers for a safe and code-compliant stair with risers that are all within a 1⁄4 in. or less.
Start with the skirtboards
The stairs I work on all have painted skirtboards, which I make out of 16 ft. by 15 1⁄4-in. MDF shelving boards ripped to 13 1⁄2 in. wide. Our framers always leave a space between the outside stringers and the walls for the skirtboards to drop into. Most of the stairs we build are quite long, so I have to splice the skirtboards. Besides allowing you to work with a smaller, shorter section, another advantage of working with a multipiece skirt is that it’s easier to work out the transition details at the top and bottom of the stairs.
When a section of skirt is all prepped, another crew member and I set it in place. The extra hands help keep the long board from breaking, and the extra set of eyes helps to line up the skirt with the layout marks.
I fasten most of the parts with a 15-ga. finish nailer. The thicker nails hold the parts better than smaller nails. I fasten treads with screws and construction adhesive, because I don’t want callbacks related to squeaks. My painter fills the nail and screw holes in the painted parts with color-matched putty after the sealer, before applying the top coats of finish. Once the screw holes are filled, sanded, and given a light stain, they virtually vanish. I used to countersink and plug each hole, but that process is a lot of work and in the end, the screw locations are more obvious.
Transforming a well-built construction stair into a finished stair keeps my life simple; all the drywall can be completed at the same time, and I don’t have to come up with a plan to get a large factory stair into the house and then protect it. Plus, the electrician can complete all the rough wiring for things like staircase tread lights at once, without having to make a special trip after the stairs are installed.
The skirtboards are made from 3⁄4-in. MDF, which is dimensionally stable and routs cleanly. I cut dadoes in the skirtboards that accept the treads and hide their ends. To make up the total length of these stairs, two skirt sections are needed. I find it easier to connect the top one after the bottom one has been fastened to the wall. Biscuits keep the two pieces aligned at the splice.
Treads and risers are installed from the bottom to the top, which allows you to glue and nail each riser to the back edge of the tread below it. This stair has white oak treads with risers ripped from cabinet-grade pine plywood, which is more stable and less expensive than solid wood.
—Gary Striegler owns Craftsman Builders in Fayetteville, Ark., a company specializing in millwork and interior details. Photos by Roe Osborn.
From Fine Homebuilding #315
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