# Deck miters - make them tight or leave a gap?



## hugh71158

Hi,

In preparing to put some picture frame borders around my deck, it occurred to me that instead of dealing with the possibility of miters opening, it might be better to gap them - just like the gap between the boards.

Anyone done this? Would you?

I bought the Kreg jig, and the minimum 1/4 inch space is a little bigger than I want, but the trade off is the ability to use hidden fasteners. It seems that the jig performs well. Someone suggested Kreg offering smaller spacers, but I doubt that this would work - I think the smaller space would mean that you would not be able to fasten between the boards without causing damage. Or that's how my brain sees it! 

A gap if 1/4 inch at the miters - not sure if I am going to like that, but then it also might be a nice feature. As you can imagine, I haven't started cutting!

Thanks.

Hugh


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## Loren

Wood moves slightly along it's length and miters also open and close
seasonally. Open miters look dumb usually, and the edges can be
prone to chipping. I don't know your skill level with joinery - lapped
miters can be attractive but take skill to cut.

If you fix the miters with screws allow for moment inside the 
mitered frame.


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## hugh71158

I was searching for examples, and managed to find one. Here it is. Thoughts?

Allow for movement inside the mitered frame? Do you mean the boards that will be contained within the picture frame?

Hugh


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## a1Jim

Hugh
Some folks use biscuits to join miters others will toe nail deck screws through the edge. Wood expanse and contracts across the grain not length wise so if your going to miter the deck I would have a tight miter. When I build decks I don't use miters the always open up when used on hand rails. I think I've built close to 300 decks in the last 22 years.


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## Loren

wood does move lengthwise. Not a lot, but that movement is the
reason we cope rather than miter long runs of moulding on the 
inside joints. Lengthwise movement is 1% or less, but over a
10-20 ft run it's noticeable and a factor you can work with if you
choose to.

Deck tolerances are generally crude. Do whatever is convenient
for you and live with. High end work for clients is a different situation.


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## a1Jim

Loren

I stand corrected wood does move length wise but it's movement length wise in my experience is so insignificant it's not really a factor. Rough carpentry does have much larger tolerances that some might call crude. Of course fine woodworking has much different standards. Since I've done both aspects of woodworking as a contractor and a furniture shop owner for many years I must work with much different stands for rough carpentry verses fine woodworking.


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## shopdog

Hugh,

When I use a miter on a deck, I round over both edges, and butt them tightly together. The round over is much more forgiving than a regular butted joint.










or, you could try a herringbone pattern, with rounded edges. (I round over everything


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## hugh71158

ok, thanks for the info guys!

Steve, I do like the round over joint - I am guessing that you glance the router over all of your edges? Sounds good. As I typed a concern popped into my head, and that's the 1/4 inch gap with the Kreg system/ The round over will amplify that. Have you see how that looks? I think I better start chopping up some samples. 

Thanks again.

Hugh


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## shopdog

Hugh,

I never used the Kreg system…1/4" gaps are way too big. You didn't mention what type of wood you're using for decking, but it's probably gonna shrink, and leave you with a +/- 3/8" gap. I set all my Ipe decking with a 3/32" gap, and I always top screw the boards. If I'm not plugging the screw holes, I use 2.5" "Headcote" stainless steel trim heads, and I countersink them with the "Smartbit" tool. It's not a hidden screw system, but it's subtle enough for me…and my clients.
Don't 1/4" gap the miters…countersink and plug them.


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## hugh71158

Steve,

I am using western red cedar, 5/4×6.

Yeah, the gap is bothering me - the only options are 1/4 or 5/16. I expect if can't be used if the gap is any smaller, but hidden fasteners are what I am aiming for.

I have never heard of the "Smartbit" tool but I am about to go check it out.

When you say "Don't 1/4" gap the miters…countersink and plug them." do you mean miter the joints then screw and plug close to the joint?

Thanks for the help by the way!

Hugh


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## shopdog

Hugh,

The smartbit is a tool for countersinking for trim head screws. Since you're using cedar, I wouldn't recommend trim heads. Cedar is soft, so you should use bugle head screws (check out the deck screws from mcfeelys.com).
Oh yeah, you're gonna use the Kreg system.
About the mitered joints, those you could countersink with a 3/8" countersink or forstner bit, and make some 3/8" cedar plugs. Roundover the miters (1/8" roundover bit in a trim router), and set them as tight as you can.
I roundover every cut that I make on my decks. If you don't have a router, you can sand the ends.


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## rance

Steve, that rounded over miter looks real good. That wood looks like 'fine furniture' though. What is it and how does it hold up to the weather?


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## shopdog

Rance,

That's Ipe. It is a beautiful, super hard wood. It's absolutely the best wood for decking…been using it for about 10 years.


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## Brad_Nailor

I picture framed my deck , and used composite. The manufacturer recommended leaving a 1/16" gap at the corners and butts. I like Steve's idea of the slight round over..gives it a little bit nicer finished look and makes the gap less obvious…I wish I thought of that!


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## hugh71158

Hmm,

so wait - if I abandon the Kreg system (seriously considering it!) what would be the recommended route?

Screwing and plugging everything? That's a lot of plugs to cut, and a lot of finishing after they are glued in. If it's going to give me the best look, then so be it. Would that be a solid choice?

Thanks!

Hugh


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## Gene01

DO NOT ABANDON THE HIDDEN FASTENER PLAN!!!
Check out the Trex Hide Away Universal Hidden fasteners. They are a square plastic Biscuit with a screw in the middle.
Trex comes grooved along the edges to accept the biscuits. The system comes with a router bit to make the groove in the edge of solid wood. 
It's the fastest and cleanest installation I've ever used. 
As to the 45s, I gap them slightly and round over to match the rounded edges of the deck boards. 
Never had a complaint on either the fastenings or the appearance of the 45s.


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## hugh71158

Yeah, hidden fasteners is the preferred choice. But the 1/4 inch gap required to use the Kreg system if really putting me off.

Routering grooves into the wood is open to possible errors ( maybe that's my skill level showing through) and it's a lot of router work.

That said, I don't relish the possibility of screws being visible.

Argghh, confused!!

Wait, I have a biscuit joiner, that would do the slots in the required locations I suppose, if using the Trex fasteners.


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