Expert: Jamie Yocono - 4/13/2008

Question
Hi,
I want to make a simple island for my kitchen to use as a stool seating area.  I intend to use ceramic tile as the top and it will be approx 34 x 44 in.  I'm concerned about the thickness of the plywood to use to avoid warping or sagging at the ends that leave leg room for sitting.  I have considered reinforcing these ends but I'm still left with the overall countertop's stability.  Should I create a "support frame" underneath?  How can I get a solid but not overly heavy top?  Should I use plywood or pressboard?

Sorry that I'm no carpenter, not even close.

Answer
Hi Ruby,

I'll try to help with your kitchen island questions, but it's a little difficult to give you a lot of help without seeing a drawing or having more information.

For something like that island that is going to need a fairly deep overhang, I would definitely use plywood, nor presswood. It's much stronger, with it's perpendicular grain orientation. I suggest using 3/4" plywood, possibly an exterior grade so that it will not be affected by moisture.  If your tile is fairly thin, you could use a double layer of plywood, which would make it very strong, and then glue the tile down to that 1 1/2" thick panel. But usually, you just use a single layer of the plywood, with a solid wood (or tile) edging to make it appear thicker. Counter tops are usually 1 1/2" thick.

There is a way to beef it up, so that it will not move or sag at all. I just answered a (sort of) similar question about supporting wood this past weekend, and I am going to cut and past part of that answer here to give you a suggestion about beefing up your island top.

Here it is:  Let me give you a quick lesson about wood and it's strength. Wood is stronger vertically (on it's skinny edge) than horizontally, on it's flat face. To get an idea of what I mean, lay a board flat on the ground, and  prop up each end by a brick or something that will raise it off the ground a couple of inches. Step in the middle of that board, and it will flex down and probably touch the ground where you're standing. But turn that board on it's 3/4" edge and try standing on it, and it won't flex. Wood is very strong vertically, but not flat. So when you attach an apron (or edging on a countertop)  attach it so that it's vertical, and your countertop won't sag at all.

So what I suggest is this - depending on your tile thickness, you want to use either a single or double layer of plywood.  Then - I recommend using a sold wood edging all the way around the edge of your 34" x 44" top, which will beef it up and keep it straight. This wood edging is usually 3/4" thick, so that means that the actual piece of plywood you're going to start with will be 1 1/2" less, all the way around.  I would probably glue and nail the wood to the plywood.

Another suggestion would be to use the solid wood edging as a way to create the recess where your tile sits. That means, let's say your tile is 1/4" thick. When attaching the wood to the plywood, have it sit slightly higher than 1/4" above the top of the plywood. Then, when the tile is glued into place, the edging and the tile are at the same height. That way, the solid wood edging is doing two things - providing some strength to keep the top flat, and also giving you an edge to grout into.

OK, I think that should help you enough to get you started. I recommend using good wood for the edging, like oak or maple or something pretty hard, as it will take some abuse over time. Don't use pine, it's too soft and will nick/dent easily.

Good luck, write back if you need more help or have more questions.  Hope this helps!

Jamie Yocono
Wood It Is! Custom Cabinetry
Las Vegas, NV
www.wooditis.com
My woodworking blog: www.wooditis.blogspot.com