The guy who works for me is having a deck built.
He would like to use two eight foot pieces that range between 17 inches to 24 inches as a bar top instead of a railing. It is almost two inches thick.
I have seen wide planks and even table tops spilt. I have a feeling this may happen with the rain. snow, freezing and heat in our climate, Eastern Canada.
Any advice? Is there a way to do it successfully?
Thanks folks, Jon
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Replies
You'd want to somehow arrange so that the wood could "move" freely horizontally while holding it flat. Whatever you do especially needs to tolerate the wood swelling and shrinking across the grain, and the scheme should probably be designed to hold things together should the wood split (which it almost certainly will do, at least to a small extent).
Wide Plank for Outdoor Bartop
Thanks Dan, we had heard some people use a threaded rod, maybe every two feet or so, across the grain with nuts you can tighten.
Worth a shot, Jon
Wood only splits when it is not allowed to shrink. Freshly milled lumber will split on the ends, not because of some magical forest curse, but because the wood is drying faster at the end grain than further into the board. The inner board is essentially trying to restrain the end of the board. Thus, a split. It will buckle if not allowed to expand. Threaded rods placed every two feet willkeep the pieces from trying to expand which is what they'll try to do in a rainstorm.
The boards need to be kept in place via a method that allows free expansion and shrinkage. Consult a good woodworking book for a variety of ideas. Your local library will have several to choose from.
If the boards are stable, I'd join them with biscuits.
With outdoor exposure, the top is going to see sun and the bottom shade. The top will see liquid moisture, the bottom won't. The best way to stabilize the top would be to coat it in epoxy. All sides; top, bottom, edges.
First brush on a seal coat. Then do a flood coat. They usually flow out to about 1/8" thick. Some countertop epoxies are marketed as "bar top" or something like that.
Epoxy needs UV protection, you can then apply a UV protective finsh over that.
If you want to avoid UV sensitivity from the start, marine spar varnishes will give good UV protection. Use mulitple coats to build up to your final mil thickness.
If you use threaded rod, if can sometimes cause more problems than it solves. When the wood tries to expand, the restriction fo the rod will cause the wood fibers to be crushed. When it contracts, the edges can shrink away from the end nuts. You tighten up the nuts. The expansion/crushing cycle repeats. The wood can eventualy crack along the weakened fibers.
For a wide plank countertop, let it move as you'd let a solid wood table top move. You can anchor one edge from below nice and tight. For the other anchor points, use oversize holes, use washers, and just snug the fasteners so the top can barely move if needed.
I don't think I'd bother fastening the two pieces together.
Joining
You know I didnt ask how it was going to treat the ends. The idea of using breadboard ends would be decorative and it provides protection from twisting would be great.
Connecting the two pieces is another can of worms I suppose. Does he do a mirror set up with the 17 inch join and the 24 on the opposing ends or connect at the widest ends and narrower out?
Jon
Epoxy Coating
Good advice Mongo. Freedom of movement and sealing all surfaces will help this last longer than a clear stain or sealer.
I am familiar with spar varnish but I didnt know you can apply another UV protection coat over a finish coat of epoxy.
I had thought using lag bolts underneath with washers would be the ticket to allow full movement. And he only needs to snug one side so that will keep it in place.
This look is still a lot of work to maintain. Coatings are going to breakdown at some point and it will discolor it seems.
Jon
think like a boat builder
Varnish over epoxy is very common in boatbuilding.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CD0QFjAC&url=http%3A%2F%2Fwww.westsystem.com%2Fss%2Fassets%2FUploads%2Fvarnish.pdf&ei=lwzzU4K4Dda2yASn5IKoBg&usg=AFQjCNGOUQImNRH9UupblBx8Cz1Jv4TeXg&sig2=HQiEYYhff_hi_Qkp-_QWNQ&bvm=bv.73231344,d.aWw
I'm planning another boat in about 4 years.