Expert: Jamie Yocono - 4/11/2009

Question
I am building custom floating stairs out of douglas fir (2+" x 12" x 36" true) which will be supported from beneath with a 1/4" steel plate 4" x 18" affixed to 4" square tubing.  Which direction should my rings run for maximum stability?

Answer
Hi Adrienne,

There has been much discussion about the concept you mentioned -- what is the correct way to orient the rings when working with wood.

Many woodworkers believe that the wood cups in the direction opposite the annual rings. So when they are gluing up large panels of wood, they tend to alternate the direction of the rings. The common thought is that this practice will even out the surface of your panel. And while it's true to some extent, more and more woodworkers are now simply gluing up panels without consideration for the rings; their main concern is for grain and color aesthetics.  They want the most attractive panel possible, regardless of the directions of the rings.

So while everyone used to alternate the rings, the truth is - many woodworkers have rejected that way of thinking.

What's the correct answer?  I consulted the "bible" for the answer to your question. That would be "Understanding Wood" by R. Bruce Hoadley. The photographs in his book certainly show that wood tends to cup in the opposite direction of the rings.

So the bigger question is - if your wood is going to move with seasonal changes, would you rather have a crown on your stair tread, or would you rather have two high edges, on the front and back of the tread?

If I were making these treads, I would probably bring the wood into the home, let it acclimate as long as possible, to see if it moves. If it does, indeed move, I  would consider flattening the treads on a planer, to get them true again. And then I would run them with the rings cupped up, so that any movement would create a small crown on the top of the treads. My reason for this is that our feet are amazingly sensitive, they can detect small differences in flooring. I think if your treads have two high edges on the treads, as opposed to a small crown, you could trip on those high spots. It's amazing how our feet find little imperfections like that.

Hope this helps,

Jamie Yocono
Wood It Is! Custom Cabinetry
Las Vegas, NV
www.wooditis.com