Author Topic: Deck guard rail - mortise and tenon?  (Read 3105 times)

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Offline jarbroen

  • Posts: 80
Deck guard rail - mortise and tenon?
« on: May 30, 2018, 02:16 PM »
Howdy y'all. :)

Short version of the story - bought a nice house last year that's almost 20 years old.  A lot of hidden, deferred maintenance.
I started back in March on the 'deck rebuild'.  Just planned on replacing the rotted decking and hopefully saving the treated framing.
Hmm, got to the deck ledger and noticed rot behind it... pulled all the deck framing, sheeting and had to cut rot/bugs out of rim and plates.
Anyway, 2 plus months later I'm finally working on the deck. :)
Framing is started and I'm planning the railing.
The decking, 4x4 posts, 2x4 rails and 2x2 pickets are all Batu/Balau.  Sounds like the kiln dried version I got should be pretty stable.

My big question is if anyone has any gotchas on doing a complete mortise and tenon for the rails and pickets?  The rails will be on edge, top and bottom, with pickets in between.  I'll probably cap the posts and rail with a 5/4x6 deck board.
I have a Hybrid Pantorouter and have already made a couple projects with mortise and tenon(walnut side tables, Kapex station - Peter Parfitt style).  I've had a good learning experience and fixed a couple of 'whoops'.
I'm not so worried about the pickets into the rails.  Glue and clamp and those should be stable and stronger than pickets that are just end screwed.
I'm wondering about any potential issues where the rails mortise into the posts.  I'm planning a 1/2" wide by 2.5" tall tenon on the 2x4 rails.  I will probably use Titebond III - I think that one is water 'resistant'.  I'm also thinking I will add a screw on the underside of the rails where they join the post just for extra security.

Does this sound safe and secure for a deck guard rail?  I know the M&T will look great, unless the joints pull and split.  The unknown for me is how sturdy and strong this will be.  The posts will be bolted with Simpson ties for extra strength.  I don't want the rails to be the weak point.  Oh, the rail spans are all about 6.5'.

Thanks guys!

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Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon?
« Reply #1 on: May 30, 2018, 03:22 PM »
Since the thread is worthless without pictures.  Here's my Hybrid Pantorouter buried under Batu.

Offline Peter Halle

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Re: Deck guard rail - mortise and tenon?
« Reply #2 on: May 30, 2018, 04:34 PM »
I will ask a delicate question:  Does the locality know about your project?  If so you may have issues with getting them to approve a mortise and tenon system.  I don't know.

Personally I am not a fan of any outdoor construction that involves a hole with another piece of wood placed into it that would have the hole facing up.  Glues and sealants will shrink, crack, and water will get into the joint eventually.

That is just me.  I replace rotten wood for a living and hate to see more rotten wood.

Peter

Online Gregor

  • Posts: 1070
Re: Deck guard rail - mortise and tenon?
« Reply #3 on: May 31, 2018, 02:41 AM »
Personally I am not a fan of any outdoor construction that involves a hole with another piece of wood placed into it that would have the hole facing up.
Does this only apply to holes facing up?
And what about holes that go all the way through the bottom side piece (so no mini lakes can form inside them)?

Offline kevinculle

  • Posts: 236
Re: Deck guard rail - mortise and tenon?
« Reply #4 on: May 31, 2018, 08:13 AM »
That deck sounds like it will require annual oiling unless you plan to let it go gray.  Cleaning and oiling balusters (rail spindles) is an enormous PITA and the issues with water, rot and code compliance are also relevant.  When I rebuilt my formerly PT-SYP deck in Ipe I ditched the wooden balusters and went with powder coated aluminum balusters attached by two screws each into top and bottom 2x4 Ipe rails with a horizontal 2x4 cap rail.  Quick installation, looks good and much stronger and easier to maintain than wood balusters!



Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon?
« Reply #5 on: May 31, 2018, 10:26 AM »
Yup, it will require oiling every 1-2 years.  And I know pickets are a PITA.  My wife and I looked at all kinds of options - cable, metal pickets, etc.  We just like the look of a good wood railing the best.
The pickets are already delivered anyway.

No permit or municipality involvement.  I'm right at the 30" 'permit not required' deck height and I'm doing a replacement vs. new deck.
I understand the hole for water issue.  I just replaced a lot of rot damage and will do everything I can to minimize that risk in the future.

My main question is if anyone has any experience or wisdom on joining the rails to posts with mortise and tenon?  That's really where I'm worried about strength and safety.  M&T joints are typically pretty strong - stronger than a couple of angled in screws.  I'm just wondering if there are any hidden caveats I should be aware of for that connection on an exterior deck rail.

Offline Rob-GB

  • Posts: 1078
Re: Deck guard rail - mortise and tenon?
« Reply #6 on: June 01, 2018, 04:12 AM »
I'd swap out the titebond III for a good brand polyurethane glue as it will expand and fill any voids left in the mortise hole is waterproof.
For added joint strength you could drawbore and peg them ( no need for long clamps  [big grin] )
 
These gates are made this way six years on and they still look great.

I discuss the drawbore method here


Rob.

Problem? No such thing! Only a solution waiting to be found:- RJ

"A $2 guppy swims......" Deke

Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon?
« Reply #7 on: June 01, 2018, 02:35 PM »
Rob - the gate and stairs look awesome! 

Thanks for the feedback on the glue.
My dad(long time remodeller/builder) called last night and I was explaining the issue.  He had the same recommendation on the glue.  He suggested Gorilla glue.  It's a water based PVA. 

He also asked me how many years I have to complete the deck... lol
I think the drawbore and peg would add an extra 5 years to my completion time.  [big grin]
My dad said I could borrow his old school door clamps for the rail to post step.  My sections are just over 6ft.
I will definitely look into the drawbore and peg when I have time to make more furniture.  I have a huge honey-do list.
« Last Edit: June 01, 2018, 02:38 PM by jarbroen »

Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon
« Reply #8 on: June 22, 2018, 11:14 AM »
Some might call me crazy or foolish but I went ahead with my mortise and tenon plan for the railing.
Definitely a lot of work and a PITA at some points but it's pretty darn cool making it and putting it all together.

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 seems like cheating using the Hybrid Pantorouter but it's still time consuming to make all the mortise and tenon cuts.

I'm using Thrulok with at least one Simpson DTT2Z on each post.
After doing research on glues I ended up sticking with my original plan of Titebond III.  Gorilla glue would have screwed me 10x over with it's short work time and messy expansion.  Titebond III has a longer set time and it's also 'waterproof'.  The specs and reviews made it sound like a perfect fit for this project.

I made my tenons 'furniture' tight which proved to be a major kick in the butt trying to fit a rail section to post.  I've eased the rail tenons a bit and the subsequent sections have gong together much better.  Still a pain getting a whole section into place.

Offline Cheese

  • Posts: 5156
Re: Deck guard rail - mortise and tenon
« Reply #9 on: June 22, 2018, 12:22 PM »
...but it's pretty darn cool making it and putting it all together.


I'd believe that...a pretty good feeling.  [big grin]  It looks real nice.

Is there a reason you didn't just use a #10 or #12 Sipo Domino in each end of the picket and also in the rails?

Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon
« Reply #10 on: June 22, 2018, 02:23 PM »
...but it's pretty darn cool making it and putting it all together.


I'd believe that...a pretty good feeling.  [big grin]  It looks real nice.

Is there a reason you didn't just use a #10 or #12 Sipo Domino in each end of the picket and also in the rails?
Thanks, I appreciate the feedback!   
I have a few(okay bunch) of Festool products but the Domino isn't on the list.  I was super close to buying one but spent that money on the Hybrid Pantorouter(HPR).  Sometimes I wish for the simplicity of the Domino but in the end I appreciate the versatility of the  HPR.  Through tenons in cool shapes like diamonds or way easy to make box joints.
I like power tools to make life easier but then I somehow make things more complicated.  [huh]

Here's an installed shot.  Looks a little messy since I haven't cleaned my goobers yet.  I get a little glue happy. :D
The top is also getting a 5/4x6 decking cap.  I'll square off the sides so it looks dimensional like the rest of the railing material.


Offline Cheese

  • Posts: 5156
Re: Deck guard rail - mortise and tenon
« Reply #11 on: June 23, 2018, 08:30 AM »
Here's an installed shot.  Looks a little messy since I haven't cleaned my goobers yet.  I get a little glue happy. :D
The top is also getting a 5/4x6 decking cap.  I'll square off the sides so it looks dimensional like the rest of the railing material.

That's a nice shot...it looks very nice, more like a piece of furniture than a deck. [big grin]

Will the decking cap be beveled and will it also have drip kerfs cut into it?

Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon?
« Reply #12 on: June 23, 2018, 10:02 AM »
I’ll ease the edges on the cap so it’s not a sharp corner.

Thanks for the reminder on the drip kerf, I had totally forgotten about that!

Offline jarbroen

  • Posts: 80
Re: Deck guard rail - mortise and tenon?
« Reply #13 on: July 23, 2018, 12:16 PM »
Finally got all the decking on.  Now just stairs and fascia left. :)