Plywood desktop strength

[Barry]

I am planning a built-in desk, plywood (3/4") with a plastic laminated top and solid wood edging. The top will be fully supported along the back and one side, and one leg to support the open side. The dimensions are rougly 33" x 84". I have seen other discusions here about plywood bending and support requirements(ribs,) but not for this case, where it is fully unsupported along only one edge (a long one.) With minimal weight requirements(I don't plan on putting any lead curios on the desk,) will I see much bending in a typical sheet of plywood? Any help much appreciated. Barry

[Traves W. Coppock]

On 31 Dec 2003 00:54:11 -0800, handy [e-mail] (Barry) Crawled out of the shop and said. . .:

yep. its gonna sag over time,,,and not much of it at that.

[Jeff Cochran]

Screw a length of angle iron about 8" in from the front edge, that will give you all the support you'll need. Assuming you're not standing on it. :)

Jeff

[roger]

If you insist on plywood, you'd be better off if you incorporated it into a torsion box frame with more supports than you're planning. If you don't lnow what a torsion box is, ask Jeeves or do a google on it. This forum dosn't have space to fully explain it--ya need a diagram or picture. Roger OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

[Ian Dodd]

I recently finished a custom built-in desk of 3/4" baltic birch plywood for my home office. I have a horseshoe shaped alcove that is

11' wide at it's open side with five facets, none of them the same size or any of the angles symmetrical. The desk is about linear 28' varying in width from 15" to 36". I spaced korbels of double thick ply (1.5") about every 18" that support the top. Between the korbels I also have a single thickness of ply running vertically (behind which I hide all power and computer cables) about 8" in from the wall. The top is bicuit jointed to the korbels and ribs. In one corner is my computer's 19" CRT monitor. In the other is my wife's computer (an all-in-one CPU/monitor). Before I loaded it up, I stood on the desk (200 lbs.) to see how it would flex. Out of curiousity I put a straight edge on the top every once in a while to see if there is any deflection. So far, nothing (3 months). Hope this helps.