I am planning to build an 8 ft long by 2 feet wide built in desktop for my son’s room. As a general rule, should I go with 3/4 inch plywood thickness or double it up to 1 1/2 inch as the desktop will extend for 8ft? Thanks.
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What will the span be? If only supported at each end, then you definately need more than 3/4".
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Thanks guys, I am planning on supporting it with cleats on the back and sides, and legs in the front.
That's still a major span for a desk top. Maybe run a 2x4 12" back from the front edge of the desk as a "floor joist" for the ply, supported on each end. Or some kind of knee brace. "Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I've got a 10' post formed lam counter (no backsplash/bullnose front) cut down to 26-1/2" with drawer sets at either end and a center console for the printer/paper.
The two openings are 32" wide and have no flex, and are cleated at the back. Computer sits in the middle.
OK, with legs in front you can get the span down to less than 42" in the center oppenning and be fine with 3/4" play and an underlamination. Make up the top by cutting it to fit the space, take it out to the workspace, then glue and clamp a 1x4 flat on the underside so the 1x4 is flush with the front edge of the ply. Do this in succh a way that you are creating a slight crown up of about 1/4" . After the glue has kicked, you can install the top in place and add a piece of trim to coiver the endgrain of the ply. Making that piece 1-1/2" will cover both and add to the strength and appearance.
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Thanks to everyone who replied. You guys are the best. I have a lot of great advice, and will let you know how it turns out!
Are you talking about spanning 8" without any legs or cabinet/drawers in between?
Usually anything spanning more than 4' requires a serious bracket, something like an L attached to a wall stud. For the top, I would think 3/4" plus 3/4"+ laminate ?
Mike
Trust in God, but row away from the rocks.
how about a 1x2 or larger biscuit joined or nailed to the face to stiffen it up and give the thickened edge appearance?
Cleats on both sides and the back secured to framing. Big piece of angle iron across the front that attaches to the side cleats. Cover angle iron with apron. MDF is a nicer desktop then plywood whether it's painted or covered in a wood veneer. I'd make it 1 1/2" solid thick.
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FYI, you could get enough rough edged 8/4 oak to make up the table for about $150 and I'll bet that would span the distance without any frontal support. It would take a little time to massage it into a finished piece, but by the time you add up what it takes to cut the ply and add a leg you're cost in personal time is racking up.
Cheers
PS. You could also separate the 3/4 ply with 2x4's on the sides and span the distance no problem with no legs on the front.
Beer was created so carpenters wouldn't rule the world.
You could do a 3/4" top but just have room for a stretcher(s) underneath like you would build a table. Do it as a recessed decorative front and one in the back where it really doesn't get in the way.
8' is too a long way to not have anything underneath, even if the ply is doubled up. You're going to have sag in no time.
Maybe you want to build a torsion box with a web of straight hardwood and a 3/8" skin. Build it up to maybe 2".
That's how hollow core doors are made except with cardboard.
I'm with you Jer...
torsion box all the way.even doubled 3/4 ply is gonna sag over 8'..
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I have Transcended the need for Pants....oooohhhhmmmmmm......
For full freespan of eight feet you want at least 1-1/2", maybe 2" depending what sort of wood
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