# trim for simple built-in desk (edge moulding and plywood joint)



## RustyShackleford (Aug 8, 2013)

I am building a simple built-in desk, out of two sheets of big-box store hardwood (red oak) plywood, each about 33x77" (so the desk is 33x154" overall). It goes completely across one wall of the room, so the back edge and the two ends of the plywood butt up against the walls. There are gaps of up to 1/4" where the plywood meets the drywall, and a tiny crack where the two pieces of plywood abutt.









I am wondering how best to trim these gaps. Oak quarter-round shoe mould at the edges (or the kind that's sorta like quarter-round, except taller than it is wide) ? For the crack between the plywood, I was just going to use wood putty.


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## GeorgeC (Jul 30, 2008)

What is supporting this plywood over those 154 inches? That is more important than trim as a first problem.

gmc


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## RustyShackleford (Aug 8, 2013)

GeorgeC said:


> What is supporting this plywood over those 154 inches? That is more important than trim as a first problem.


Supported by cleats lagged into wall studs at ends and along back edge. Supported 4" back from the front edge by a 2x8 laid on its side, supported in the middle by a drawer stack.

Beam calculation gives about 1/4" deflection in center of un-supported span of 2x8, with 100lb point load (bigger guy than me leaning hard on elbows). I could stiffen it up with some steel angle or a 2x4, but 1/4" seems ok; but I guess that flex could affect whatever fill I use for that joint between the two pieces of plywood.

Maybe 4" is too much to cantilever the plywood off the front of the 2x8 too - I'm not sure how to figure that.


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## phaelax (Dec 24, 2018)

Instead of the quarter round, I'd go for a cove molding.
For the crack between the two sheets, can you rip the edges so you get a cleaner more flush joint?

I did a similar desk a few months ago 8' long. The back was against the wall and supported by a 2x4 underneath running the length of the wall secured by a couple lag screws into several studs. The two front corners of the desk I used black iron pipe. I haven't noticed any flex but my top is a butcher block countertop, so a bit thicker than plywood. It's not perfectly flush with my crooked wall, but I didn't use any trim. As far as appearance goes, it looks like a standalone desk.


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## RustyShackleford (Aug 8, 2013)

phaelax said:


> Instead of the quarter round, I'd go for a cove molding.
> For the crack between the two sheets, can you rip the edges so you get a cleaner more flush joint?
> 
> I did a similar desk a few months ago 8' long. The back was against the wall and supported by a 2x4 underneath running the length of the wall secured by a couple lag screws into several studs. The two front corners of the desk I used black iron pipe. I haven't noticed any flex but my top is a butcher block countertop, so a bit thicker than plywood. It's not perfectly flush with my crooked wall, but I didn't use any trim. As far as appearance goes, it looks like a standalone desk.


Finished this over a month ago, but thanks. The quarter-round looks ok. I did indeed get a very clean joint between the two sheets - just put a little putty in there, it's all good. 

Also, the electrically-controllable column, that makes part of it convertible into a standing desk, is awesome.









lift mechanism for adjustable-height desk


I hope this post is appropriate, mentioning a vendor ... I want to build a small desk (actually the short arm of the "L" for a larger desk) which can be easily adjusted for height, to be standing desk when raised, or adjoin the longer arm (to form an "L") when lowered. I came across this...




www.woodworkingtalk.com


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## firehawkmph (Apr 26, 2008)

Whenever I use plywood like that, I make the edging out of something a bit thicker and machine a dado on the back side so the plywood fits in the groove, not too tight, but without slop. I’ll leave it stick up above the plywood top about 3/16” and about the same below. Round the edges over so it’s not sharp and it works well to provide support for the edge and helps eliminate sag. For the seam in the middle, if you have the ability, I would cut a 45 degree angle on each piece and seam it together like that. If you do it right, some light sanding should give you a tight seam with no filler needed. 
Mike Hawkins


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