What kind of joinery on deck railing.

[suds]

My deck is 35 years old and the top railing and supporting structure need replacing. What kind of joinery would be the best/strongest?  We have snow and ice and very warm summers so it sees extreme temps.  I was thinking of using a dovetail joint but not sure if that would be good for wood movement.

 

[Dogberryjr]

I'll be watching this thread with interest.

 

[Sparktrician]

Given that mitered type of rail joint, I'd be very tempted to use a lock domino joint to hold it all together.  Given that the deck is outdoors, I'd be absolutely certain to use sipo mahogany dominoes.

 

[kevinculle]

Commercial nylon rail brackets provide a stable and durable rail to post connection.  Traditional woodworking joints like the dovetail are ill suited to an environment like yours (or mine) as the effects of water and ice will work over time to stress and loosen the joint.  Here's a picture of my deck which I initially built over 30 years ago with PT-SYP and redid 3 years ago in Ipe.

 

[Master Carpenter]

Screws, preferably stainless ones.

 

[rst]

The decks that I have done I've used a half lap joint, epoxied and screwed from underneath.  Exterior butt miters will never stay together.

 

[NL-mikkla]

Why not construct it the way it was, maybe a little nicer without screws exposed and such.
It held up for 35years, imo good enough

 

[jarbroen]

Not sure what 'best' or 'strongest' would be but I'm currently rebuilding my deck railing using mortise and tenon.
I'm in the Pacific Northwest - not really an extreme environment. 

The posts have .5" x 2.5" mortise with matching tenon on 2x4" rails on edge.  The rails have .5"x.75" mortise with matching tenon on the pickets.
It's kind of a pita to make and install but I really like how solid it's going together and it looks great.
A very expensive experiment.
I posted a couple pictures in my thread in the Home Improvement section.