Hey, I’m building a deck and the design calls for mitered joints on some of the corners. We’ve got some good looking redwood 2×8’s to be installed on edge, wrapping the deck and covering the P.T. framing. Our wood is a little green but it’s been drying in the shade and I know our corners will look great when we’re done. I also know that tight joints don’t exist for long in nature, so I’ve advised the client that they will open up in time. That said, I’m looking for input/tips for getting the joints to stay as tight as possible for as long as possible. My ideas so far:
1.Drying the wood as long as the schedule will allow before cutting (Kiln dried is not an option because we’ve got all the wood).
2.Using similar wood (as far as ring pattern, grain etc.)on both sides of the joint wherever possible, keeping annular rings curving away from the face of the joint (any cupping would hopefully make the fascia convex, hopefully).
3. plans call for 2×8 fascia to be bolted to framing approx. 3-4″ from the ends (washers and bolts countersunk and plugged), but I thought I’d also use trim head screws at a 45 degree angle to pin the corners together.
4. Since the 2×8’s are non structural here, I’m thinking about making 4 or 5 parallel cuts along the back of each board (stopping short of the joint) to relieve tension and fight cupping. I was thinking that 1/3rd of the board’s thickness should do.
I’m wondering if it would make sense to seal or oil the end grain before assembly even though it will be months before the rest of the wood gets treated.
Any thoughts or additions? I know I’m trying to fight the inevitable, but constructive advice would be appreciated.
Edit: p.s. it’s been a few years since I’ve had to think about this, but what is your favorite product for sealing/oiling the wood, when the time comes?
Edited 7/30/2007 6:17 am ET by saulgood
Replies
You might want to look at the festool domino- I hear that they either have or will soon have a biscuit designed for exterior work.
Your idea of screws would probably help some--maybe with some sort of exterior waterproof glue (would at least seal the end grain). (I've heard that inserting dowels in holes drilled vertically through each side of the miter first will allow the horizontal screws to bite into something besides end grain). Could even go nuts and drill horizontally from one side of the miter into the end grain of the other side, then glue in a dowel and lastly, put a screw from the other side of the miter into the dowel.
Was wondering too if cutting a wide saw kerf across the miter (or a narrow router groove) and then gluing in a spline and nailing down through the spline at each side of the miter might help hold it shut. Could even use a contrasting (but suitable for exterior) wood (or dye the spline).
Consider a joint known as the miter lap joint. Viewed from the top, you see a tight miter. But there's a lap joint underneath. You can glue it a peg it. I tried this on a redwood deck and it's held up well. Best way to cut it is to rough it out by kerfing with a circ saw, then make the final cuts with a router and a pattern-cutting bit.
good luck.
I'm having trouble picturing the joint you describe - would it work for an "on edge" 2x8?
Cool ideas,everybody. I love the cross-grain dowel insert - it's invisible and simple so I might as well do it... Thanks again for all the responses!
Yeah, for corners in horizontal pieces consider a half-lap miter. But even there you have trouble as redwood shrinks much differently in width vs length. Won't work well in a vertical (on edge) piece, though. For the vertical pieces there are various dado-type miters you can use, but probably more trouble than they're worth.
You can also glue. I find resorcinol works well with redwood, aside from leaving a dark glue line. Urethane will work, but is too messy for "fine" work.
Another option for horizontal pieces would be to use the "dumbbell" fasteners they use for countertops, etc, perhaps combined with pegs to hold things in basic alignment. For on-edge pieces I don't know of any good options that don't require an exposed fastener, but there are some exposed options worth considering made for KD furniture, etc. (Many of these are bronze and should be fairly weather-resistant.)
Re finishing the wood: If you want the "natural" look, apply the finish now, to all 6 sides. If you wait until completed the wood will have weathered unevenly and you won't get that "natural" look (as unnatural as it actually is).
PL Premium. Almost guaranteed to hold the joint together.