Wide Solid Wood Stair Treads

Relief cuts on the underside of a wide stair tread can reduce the risk of cupping in service. April 4, 2011

Question
We have a staircase for a customer and they want it in beech. We are going to be buying the balustrade but were planning on making the treads and risers in house. I have a couple thousand feet of beech (KD) that has been sitting in the shop for quite some time. The customer had asked about one piece treads which I resisted however going through this material we have several very nice boards in the 12"-16" width range. My gut feeling is that it’s asking for trouble running one piece but I have never used beech for treads and was hoping for some input. My original plan had been to glue up narrow pieces like a conventional tread.

Forum Responses
(Architectural Woodworking Forum)
From contributor Z:
I have used relief cuts in the back of solid treads to enable flattening and remove tension. Add to that gluing with construction adhesive and nailing. If the beech has been stored for years and you have many wide boards that remain flat then that’s a good sign.

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From contributor M:
One thing to check would be the relative humidity difference between your shop and the jobsite. What has remained flat in your shop could move in a different environment.

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From contributor J:
Also, look at the ring orientation on those boards. Wide planks tend to be flatsawn, which is more prone to cup than rift or quartersawn.

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From contributor I:
Ditto the relief cuts on the back. Be aggressive, and put a bunch of saw cuts better than half way through the tread, then glue and screw them down. There was a stair company that did work for us that bragged on their one piece solid treads, problem was every single one of them cupped without fail when not relief cut. His installer ran a Skilsaw down them on the jobsite because he couldn't get the shop to do it.