Wood Strength Question

Hey y’all, my friend wants me to build him a desk and I’m a little unsure if the materials he asked for will be strong enough for what he had in mind. His design has a 6’ x 2.5’ x 1.25" main table top in a herringbone pattern. He wants it to be made out of walnut (.5in thick) with a plywood backing (.75in), but I’m not sure that it will be strong enough. The design lacks any support in the middle, so it’s just the tabletop spanning 6 x 2.5.

If anyone has any advice, it would be greatly appreciated!

Do you have any drawings, plans or sketches?

They haven’t sent me anything like that. As far as I can tell the desk legs are made from some decently thick steel and are going to support the wood portion on three sides, leaving just the front edge unsupported.

Sounds like a good use for angled steel or C channel. This is not the most elegant execution, but I like this guy and he does demonstrate the flex difference nicely – How To STRENGTHEN WOOD WITH STEEL! (Make Your Wood Projects Stronger With METAL/STEEL...#1 Trick!) - YouTube

C channel recessed into the wood, would probably be your best bet.

Is there a reason why it has to be 1/2" walnut? As in your friend already has it in that thickness? If not, you would have to make it that thick because at a minimum if you get it S4S it comes 3/4" thick. I say keep it at 3/4" along with the thickness of the plywood and the stifness of the glue once is cured should give you a nice 11/2 thickness which puts you right at the minimum limit of span/thickness ratio. If you use a 3/4" or thicker board on the edge (to cover the plywood) will also increase your strength to prevent it from sagging on the front edge. No matter what you use, metal or otherwise, you have some added steps/work. I think your biggest problem is going to be to keep it flat (not sure what you are using to adhere walnut to plywood).

There isn’t a reason for it to only be a 1/2" walnut or to have plywood at all. It was just something that was requested and it seemed to me like it wouldn’t be possible for the amount of weight it would need to hold. Based on the responses here, it seems like the general consensus is that it won’t.

Thanks for all the input, y’all. I’m going to send him some recommendations and see what he wants to do.