Q: I read (and kept) your column about how to restore a Victorian’s front staircase. I, too, own a Victorian house, in Oakland, Calif., with wooden stairs that need to be restored. Your article was very helpful, but I have a couple of questions about replacing them. What is the best new lumber to replace the old 2-by-12s? I would expect to paint them. Also, should I use wood screws to fasten the treads?
A: The rainy season is upon us. We strongly advise against installing new wooden steps until drier weather and warmer days arrive. If you install any kind of exterior wood during the winter it will absorb moisture. This increases the chance that the paint will fail when the wood shrinks in drier weather. Wait until spring. You’ll give the new treads and risers the best chance to withstand the inevitable expansion and contraction and hold the paint.
We doubt that your steps are original to the house. Someone in the past has replaced them with 2-by-12s that did not match the existing treads. Originally, the treads were probably 1 1/4 inches thick by about 11 inches wide. This is known as 5/4 stair stock. Stair treads are milled from clear vertical-grain Douglas fir. Doug fir treads are expensive, but in our view their strength and stability make them worth the money. We advise you to make the investment and go with the original look.
But if you want to use 2-by-12s, again Doug fir is the way to go. Buy “select” grade and go through the stack and choose the best boards. Look for vertical grain with close growth rings and no warping or checks. These are signs of stable boards. Once you’ve selected the boards, bring them home and stack them off the ground in a dry place with spacers between the boards for a couple of months. This will allow the wood to slowly dry, which reduces the risk of warping.
When spring arrives, install the new steps. First, make sure the stair framing is sound. If it’s not, make the necessary repairs.
Before you nail down the treads and risers, do a “Cadillac job” and prime them first. Prime each piece on all sides with two coats of a high-quality oil-based primer. It’s important to prime the side of the wood not exposed to the weather so that the wood absorbs and releases moisture evenly. This is called “back priming.”
Apply the first coat of primer and let it dry for a couple of days. Give it a light sanding with 150-grit sandpaper and apply the second coat. Let that dry for a couple of days and sand lightly again. The sanding will ensure a uniform finish when the finished paint is applied. During installation, when you cut the treads and risers, keep a coffee can with a little primer and a small brush nearby so that you can prime the cut ends of the boards before nailing.
Don’t use screws to attach the treads and risers. Screw heads are larger than finished nails and need to be counterbored and filled to get a uniform flat surface. We just don’t trust any of the fillers to remain in the holes.
Rather, use 16d finishing nails (three per tread) and construction adhesive. Drill the tread before nailing so that the nails go in easily and the wood doesn’t split. Pay attention to the end grain of each tread and riser. If the end grain forms a semicircle, known as “cupped,” place the wide part of the circle down.
A nice touch is to let the treads hang over the risers about an inch and apply a strip of cove molding where the riser and the tread join. It’s not much extra work and makes for a handsome step.
The final steps are to caulk all the seams with acrylic caulk, fill all the nail holes (we’ve found window glazing compound works best because it stays flexible) and finally, paint the steps. Two coats will do.