I’m going to replace my stair treads because they’re starting to rot and are hard to keep paint on them. The old treads are 5/4x12x7′ and are either doug fir or yellow pine, although I don’t remember that far back. The stringers are in very good shape(P.T. wood). I was considering using a 5/4×6 and leaving an air gap where the treads sit on the stringers. I was also going to use P.T 5/4×6 but was afraid of all the moisture in them. We have Home Depot and Lowe’s here and their P.T. lumber just looks like it came from the hold of a sunkin ship. I know I’ll have to find a “REAL” lumber yard to find treads seven feet long. I wrote “BREAKTIME” before and only received one reply. It was all about moisture and the levels in my lumber. Can’t I buy lumber at a moisture level that will let me prime and paint and do this project in a few days? Any help you can give will be appreciated.
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Replies
One of the reasons your stringers are in such good shape is they were covered from the elements by the 12" tread. I do however find it odd that the treads are rotting and the stringers are intact.
Chech the bottom of the stringers with a knife or an ice pick for rot and replace if you find any.
Using a couple of 6" boards in place of 12" treads is pretty standard on decks. If you are from a wet area (eastcoast/ westcoast) cover tread cut on the stringer with a 2½" strip of tarpaper or 90lb roofing felt before nailing the 6" boards.
The old PT lumber recommended painting after one year. I dopn't know about the new PT lumber called ACQ but the old stuff was said to have a wax coating.
Gord
If you want to paint anyway, try using fir, redwood, or mahogany. It'll have a much lower moisture content then PT right out of the yard and any of those species will do just fine in the weather, especially with the paint job you're going to do.
If you're stringers really are still in fine shape, you could apply a heavy coat of primer to the tops before you install the new treads. Sometimes on exterior wood that isn't directly exposed (visually) I'll seal up the grain with a coat of whatever exterior wood glue I have in the truck. Usually Titebond II. You could also put down a little strip of self adhering membrane like I&W shield or Vycor or something on top of the stringers instead of the glue.