# homemade box beams



## fishhead

Has anyone here made and used homemade box beams?

I thought I saw some on a truck today so that's what reminded me of them.


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## texican

I've seen them... Nice facing wood, with structural elements inside, usually flakeboard.

I made a 6x10x30' beam for my first house...

Now, I'm making solid beams on the sawmill... found I can use the 'tops' of trees that normally would be left to rot in the woods and make some fantastic beams out of them. Been sawing this afternoon...


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## jwal10

Structural or decorative? I make a lot of decorative ones for ceiling beams from old barn boards and rough sawmill lumber stained....James

http://www.fauxwoodbeams.com/wood-b...ag=821341922&gclid=COqy1q6286wCFcYZQgodDB2dqg


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## fishhead

I was thinking structural.

They seem like something a owner builder come make and handle much easier than beams. It looks like a person could make I-beams out of plywood similar to the manufactured ones.


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## TnAndy

I made a couple when I built my house in 1985. But I did them more like floor trusses, only using 2x6's, and then covering the sides with 3/4" plywood, glued and nailed. One spans our living rm/dine rm opening, about 18', and one I used to span the garage, about 22', so it would not have a post in the center. Both of them hold up the 2nd floor, with 2x10 floor joists connecting to them.

We built them on the floor, and put a slight upward arch in them using a chalk line as a straight reference line, and blocks of wood scabbed to the floor to get the arch built in. Both of them are sheetrocked, and it hasn't cracked in nearly 30 years, so I assume they have not "given" any once they were loaded down with the second floor weight. It was total "seat of the pants" engineering, as we didn't have a building inspector to satisfy, and I sure as heck wouldn't have done it in somebody else's house, but it worked fine for me.


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## fishhead

A 22' span with only a 2x6 sandwiched between 2 pieces of 3/4" plywood?

The ones I saw had 2x4's laid flat and sandwiched in between the top and bottom edge of plywood. The depth of the plywood varied according to the span.

Other ones that I saw had an internal frame similar to trusses made out of 2x4's.

They looked really strong.

It looks like a person could make beams out of 2 pieces of 3/4" plywood with the edges set into a groove cut into a 2x4. Again the depth of the plywood could be adjusted according to the span.


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## TnAndy

fishhead said:


> A 22' span with only a 2x6 sandwiched between 2 pieces of 3/4" plywood?


Read what I said again, Fish.

FLOOR TRUSS.....not a "2x6 sandwiched between 2 pieces of 3/4" plywood"


Like this, only LOT more heavy duty.....2x6, 3/4 plywood on both sides, glued, nailed, and 20" tall with a 2x10 glued/nailed to the bottom for a ledger to hold the 2x10 joists above it.










Making your own I joists ( 2x4 with plywood web) might be sorta "iffy"....lot of engineering goes into them......look at the end, the OSB/plywood they use is set in a slightly dovetailed slot in the 2x3 top/bottom on the ones I've seen.....plus I think they use one continuous pc of OSB in the web.


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## fishhead

Thanks.


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## wharton

I've done this for headers, and it's nice because it leaves a great big void to insulate. Now that we are controlled by the nanny state, and have to adhere to the IRC code to build anything in these parts, most box beams are out of the question, unless designed and stamped by an engineer. The header idea is an exception, as the code lists detailed instructions for creating a box headers out of 1/2 plywood. On thing that surprises my framers on occasion is that adhesives applied in the field are not counted as structural by inspectors. Too many variations and possibilities for misapplication. As for beams in general, once Laminated Veneer Lumber became widely available, I pretty much stopped bothering with steel, box beams, or Glu-lams. LVL is cost effective, light for it's strength, and ridiculously strong.


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