How to build these 12' 1'x1' non load bearing columns???

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Forum topic by Sailor posted 01-14-2013 04:27 AM 2998 views 0 times favorited 10 replies Add to Favorites Watch
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543 posts in 3440 days

01-14-2013 04:27 AM

So, I am bidding on a small job where the customer needs two columns soley for decoration and not to support anything. They are to be 12’ tall and 1 foot square with trimmed out base and top. The columns are to be smooth and just a normal square shape with no trim/flutes/designs in the sides. Just a normal square column, but 12 tall… Painted….

So I’m trying to decide the best way to construct them

1) 3/4” birch or MDF? I think birch but MDF may have an advantage and just use butt joints

2) Cut the 45’ angles on the edges (8’ edges) and try to align everything up or use MDF and cut sides 12” and 10 1/2” and just make butt joints for the corners and try to make it paint well? I could put a piece of outside corner trim on the corners going all the way up….

3) How about 1/2” birch with butt joints and outside trim moulding? I like this one for cost and simplicity reasons but may require some sort of frame structure?

3) Should there be some sort of frame sections inside the columns periodically to help them keep shape?

They are basically going to be tied into a drop ceiling and not supporting anything but their own weight. Weight is a concern, but only for ease of install.

What do you all think? It’s only 2 columns so it’s not that bad.

How would you build them?

-- Dothan, Alabama Check out my woodworking blog! Also my Youtube Channel's Facebook page

10 replies so far

View Loren's profile


10477 posts in 3823 days

#1 posted 01-14-2013 05:27 AM

I would use MDF and butt joint the sides.

Somebody with more experience folding long miters
might tell you different.

Best to have a helper handy for assembly I’d say.

I would put some sort of frame in there. The column
will be heavy and internal support will help it stay
square (and joints closed) during handling.

View Mark Kornell's profile

Mark Kornell

1169 posts in 2706 days

#2 posted 01-14-2013 07:46 AM

You need a frame to hold it together in case something knocks into it. Also, unless you can find 12’ long sheets of MDF or ply, you will have have to butt sheets together on the column face.

For the corners, butt joints are the way to go. You’ll never get a perfect miter for 12’, let alone do it 8 times. And given that you’ll be fitting to an internal frame, your dimensions would have to be perfect. And the frame would have to be perfectly straight… Are you building onsite?

Birch ply or MDF doesn’t really matter, but I’d pick 1/2” MDF. 3/4 is fine, just overkill and makes the structure heavier. MDF also paints better – grain can telegraph with the ply, no matter how well it is sanded.

Screw and glue the sides directly to the frame. Do the 12” sides first, make them 1/8 or so overwidth. Fit the 11” sides in between, then use a router to flush trim the overage.

To fill the screw holes, the gaps between sheets and seal the MDF edges, use Bondo or equivalent autobody filler (with a slow set hardener if you can find it), or drywall compound. The usual wood fillers are ok to fill screw holes in MDF, but aren’t fine enough to stick to the edges well. Bondo works better than drywall compound. Sand the filler flat.

You probably want to consider a small chamfer on the corners to make them less fragile.

-- Mark Kornell, Kornell Wood Design

View runswithscissors's profile


2873 posts in 2200 days

#3 posted 01-14-2013 07:51 AM

Have you considered solid wood? Just wondering. Also, you might do the miters with a router and a straight edge guide. When working little pieces of wood, we tend to use large tools. Conversely, portable tools work better when the wood gets large (picture maneuvering a 12’ long plank through a bandsaw, trying to cut a curved shape in it, as opposed to steering your (robust, high quality) saber saw through it.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View OnlyJustME's profile


1562 posts in 2552 days

#4 posted 01-14-2013 07:53 AM

Could try a lock miter router bit.

-- In the end, when your life flashes before your eyes, will you like what you see?

View Howie's profile


2656 posts in 3098 days

#5 posted 01-14-2013 12:01 PM

OnlyJust me beat me to it. I think I’d use the lock miter bit. Once “tuned” shouldn’t be a problem to run the length. Would be much stronger joint than a butt joint. If you use solid wood it would be easier to pull the joint together and hold it. If you use MDF it would give you more glue surface. Screw wise,I’d use “conformant” in the MDF.

-- Life is good.

View jdmaher's profile


437 posts in 2754 days

#6 posted 01-14-2013 01:37 PM

I think I might just buy it.

I’ve framed in lally columns, using a plastic collar do-hickey as the “structure”, then butt jointed the sides, even using bisuits to keep it aligned. Still had to flush trim the wide sides with a router. Really hard to find near perfectly straight wood (MDF would be better, if you have 12-footers locally available), and keeping it aligned for glue-up is awkward. Painted result is nice, but not really worth the effort.

Try a Google search on “square column”. Lots are being made, much cheaper than I could make it.

-- Jim Maher, Illinois

View dhazelton's profile


2789 posts in 2471 days

#7 posted 01-14-2013 02:08 PM

If you use 1/2 inch material make up some 11 X 11 webs to go every two or three feet on the inside (3/4 would be 10.5×10.5 web). Wouldn’t need any other structure than that and they would be strong. If you have to install these in a finished space you’ll have to leave off base and caps so you can tip the column up into position without running into trouble. You’ll also have to figure out how much shorter the column portion needs to be ahead of time or build the columns in place.

View Jim Finn's profile

Jim Finn

2684 posts in 3097 days

#8 posted 01-14-2013 02:39 PM

I once built a 14’ tall cross for atop a church . I used 1 1/2” redwood. I held it together with a 14 foot long sliding dovetail with one angle cut off. So I guess it was 1/2 a sliding dove tail. I painted it and installed it with a crane. Very heavy but very strong.

-- No PHD just a DD214 Website>

View MrRon's profile


5139 posts in 3418 days

#9 posted 01-14-2013 08:47 PM

I would go with 1×12’s (3/4”x11-1/4”). Glue and nail edge to face all around. Result will be a 12”x12” square column. I would also place 10-1/2×10-1/2 frames inside top and bottom an 1 or 2 in the middle. You can add 1-1/8×1-1/8 corner mouldings for a nice smooth corner if the wood board edges are a bit chewed up.

View REO's profile


929 posts in 2249 days

#10 posted 01-14-2013 11:09 PM

if its going to be painted anyway use poplar or basswood. lots cheaper and easy to work with The lock miter is the way to go. makes the glue up much easier, and the spacer blocks are a good addition as well. I would nail or screw the top and bottom collar in place and then build around them.

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