We are starting a job that requires some benches made of flat sawn red oak. The top of the bench (seat) is 24" wide by 3/4" thick, made up of edge glued boards. The top will then be cut with a 12" radius on either end, with about 5' of straight in between.
Here is my concern… The bench then gets a 6" skirt wrapped around it. The skirt was originally made of short radiused pieces all glued around the perimeter, but has now been changed (after insisting that the whole thing will break) to thin layers bent and laminated around the perimeter, with a small v groove in between the individual boards. The top panel has no room to move, as it is captured inside the skirt. Anyone have an idea how much the panel will try to move? The finished benches will be inside an airport in California, but built in Vancouver, Canada. Is this bench top going to self destruct over the change in seasons?
(Architectural Woodworking Forum)
From contributor J:
I'd glue the front long (edge) grain only. Stop at the radiused ends and screw and plug (through elongated holes) the sides. Design the back of the seat to allow for movement.
If you do, then keep my name, because you will be needing a consultant to diagnose the problem. This work is how I make a living and I have plenty of business, unfortunately. If you do make this without special care, and the wood splits, it is possible to repair the crack using a spline. But then, when the seat swells during the more humid weather, you will see warp, etc.
The only real option here is to use veneer. I have used solid wood stairway landings in the past, but these allowed and directed wood movement to occur under a stair riser where it wouldn't be seen. To attach the glued up panel to the landing, I ran a 3/16th router bit full width from the bottom, then ran a metal cutting woodruff key cutter through the router cut. This created a "T" slot in the panel. I then drilled through from the top into the slot, slid washers under the holes, and screwed through the washers - plugging the holes afterwards.
This is a lot of work to do something that a reasonable person wouldn't do in the first place - but sometimes we have to please architects and interior designers who are not reasonable people. If your customers are not reasonable people and will not agree to veneer, then I suggest you pass on the job.