# Deck addition, how correctly brace free-standing deck?



## BulletHead (Sep 3, 2008)

Hello all,
I am helping build this addition for a friend's deck. I hope the drawings are helpful. Basically, it will be a free-standing deck, ~8' high. The current deck does have a ledger beam attached to the house but for the addition, along the house, he doesn't want to remove and cut into the clapboard siding to attach the ledger beam and would rather do a free-standing deck.

We are using 4x6s as posts and will notch the sides for 2x8 on each side of the 4x6 as beams, as seen in drawing below, option #1.

I would like to attach the new joists to the existing deck's rim joists as shown in the drawing below and run the decking perpendicular to the current decking. 

My main concern is, once posts and decking framing is up, what is the best way to brace the posts to avoid lateral forces that may bring the deck down? If I dont get this right, I will NOT be able to sleep at night, appreciate any help/advice, thanks in advance.

I have attached the 3rd pic showing some angled bracing (tried to show), but not sure if this is right for bracing.


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## Smith Brother (Dec 9, 2012)

Take a peek at YouTube deck building. Or GOOGLE 'Deck plans'

You can punch in your measurements, and they will steer you through the process. 

Dale in Indy


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## BulletHead (Sep 3, 2008)

I see bracing videos for low, 2-4' high decks, but nothing for 8' high decks.


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## Alchymist (Jan 2, 2011)

Need more information. Are the 4X6s in the ground? If so how far? Sunk in the ground far enough, with one end attached to the adjacent deck, 45° angle braces about 3' long on the outside corners in both directions should suffice. (see illustration).

You could also place a tapered block at the far end from the attached deck on the side next to the house, tapered to match the siding, and a single long lag screw through the deck 2X, spacer, siding and into a wall stud. You could also add 2X4 X bracing between uprights.


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## BulletHead (Sep 3, 2008)

The 4x6s are NOT in the ground. There is an elevated footing poured and then a j-bolt placed inside the concrete with a strong-tie post-base with a 1" standoff which will hold the 4x6 post.


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## BulletHead (Sep 3, 2008)

Alchymist, I like the idea of hitting a wall stud but how do I find the stud? Look for the nails on clapboarding? The inside is a basement, but unfortunately its finished, so I can't be cutting holes in the ceiling/walls.


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## BulletHead (Sep 3, 2008)

Another question, can I use strong-tie 2.5" SDS screws for all beam-to-post connections or should I use carriage-bolts? I want to use the same for the cross braces too, planning on using 45deg 2x8s between posts, like shown in your pic Alchymist.


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## BulletHead (Sep 3, 2008)

In this pic you can see the footings and the j-bolt in place. Is it possible to tie the posts into the cement foundation?

The span between the existing deck to first footing is 8' and another 8' to the foremost footings and house foundation footing to corner footing is 9' .


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## BulletHead (Sep 3, 2008)

Can I use wedge anchors and attach posts to cement foundation (with spacers in between) on right side to help with lateral loads?


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## Jcahill4 (Jul 21, 2013)

8' high, free standing and not anchored into the ground? Just stop there, call a contractor or engineer, people could die.


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## unclefester (Aug 23, 2013)

I do not know your local codes but what you have drawn will NOT pass any inspections here.

8" concrete in Sonatube 6" below the frost line with a 1/2" j bolt on top to accept an elevated post connector. Do not sink post in concrete ( not enough around post and concrete will fail) or sink in ground as the post will rot. You need air under post bottom to keep water from wicking up .

4x6" post or 6x6" posts with horizontal braces 2' off the ground. Attach with 1/2" galvanized thru bolts. Do not notch posts.

Top beam is 2x8" min on each side of post with thru bolts. Do not notch posts.

Ledger plate lag bolted to house ledger board or to house studs. This is the most crucial piece to keep it from falling down. Remove siding and use flashing at house connection.

Joists sit on top of beam at 90 degrees to beams.


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## unclefester (Aug 23, 2013)

unclefester said:


> I do not know your local codes but what you have drawn will NOT pass any inspections here. 8" concrete in Sonatube 6" below the frost line with a 1/2" j bolt on top to accept an elevated post connector. Do not sink post in concrete ( not enough around post and concrete will fail) or sink in ground as the post will rot. You need air under post bottom to keep water from wicking up . 4x6" post or 6x6" posts with horizontal braces 2' off the ground. Attach with 1/2" galvanized thru bolts. Do not notch posts. Top beam is 2x8" min on each side of post with thru bolts. Do not notch posts. Ledger plate lag bolted to house ledger board or to house studs. This is the most crucial piece to keep it from falling down. Remove siding and use flashing at house connection. Joists sit on top of beam at 90 degrees to beams.


Forgot to add joists should be 2x8min with joist hangers at each end. I only use 2x10's as joists to eliminate any spring.

I have decks still ridged and flat that I built 30 years ago.

Be safe


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## BulletHead (Sep 3, 2008)

I had wrong info. So the foremost posts will be ~4ft high and the middle ones will be ~5ft high. The existing deck is ~8' high. See that ledge near the middle footings, that is a drop off there.


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## BulletHead (Sep 3, 2008)

unclefester said:


> I do not know your local codes but what you have drawn will NOT pass any inspections here.
> 
> 8" concrete in Sonatube 6" below the frost line with a 1/2" j bolt on top to accept an elevated post connector. Do not sink post in concrete ( not enough around post and concrete will fail) or sink in ground as the post will rot. You need air under post bottom to keep water from wicking up .
> 
> ...



Thanks for the reply UncleFester.

So you're saying that in my drawing #1 (yellow) is worse than #3 (green)? And #3 is what you recommend?

I was under the impression with #1, all the vertical forces are directly imposed on the post and base and with #3, all the forces are on the carriage bolts which have a higher chance of failing.


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## ecr (Jan 4, 2011)

What is the spacing between the footers you have pored. Which way are your beams going to run in relation to the house. Can you post a pic of the deck you are tring to attach to. Also do not run a bolt through the siding. if you decide to through bolt the ledger, siding needs to be removed and ledger needs to be flashed. If not flashed you will have water intrusion at bolts. I can help with more info. I used to build decks for a living before I opened my cabinet shop.


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## BulletHead (Sep 3, 2008)

So the spacing between footers in either direction is 7-8'. The joists on current deck are 16" apart and run perpendicular to the house and attached to ledger. I plan on running joists parallel to the house off of the rim joist where the stairs are attached to currently and not attach a ledger to the house, so a free-standing deck (sort of).


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## ecr (Jan 4, 2011)

Here is a few sketches make sure the deck you are attaching to can carry the load of the new ledger. You would be better off using 6x6's and notching them for a doubled 2x10 built up beam. Use some peel and stick flashing on top of the beam to prevent water in between plys. I use 2x10's for my bracing.


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## unclefester (Aug 23, 2013)

BulletHead said:


> Thanks for the reply UncleFester. So you're saying that in my drawing #1 (yellow) is worse than #3 (green)? And #3 is what you recommend? I was under the impression with #1, all the vertical forces are directly imposed on the post and base and with #3, all the forces are on the carriage bolts which have a higher chance of failing.


No 3. Is the strongest for carrying weight.


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## unclefester (Aug 23, 2013)

ecr said:


> Here is a few sketches make sure the deck you are attaching to can carry the load of the new ledger. You would be better off using 6x6's and notching them for a doubled 2x10 built up beam. Use some peel and stick flashing on top of the beam to prevent water in between plys. I use 2x10's for my bracing.


I would not notch the the posts. A 6x6 is usually 5 1/2 less 3" for the double 2x10=2 1/2" of material. That should definitely hold until the collapse.

Beam construction on older buildings did notch the columns but used caste iron plates and thru bolts to replace the integrity lost by removing the material. 45 degree cross t's were also used to spread the shear load. You're not doing any of that.
The other poster recommended NOT bolting thru siding. Absolutely correct. I use lag bolts with washers bolted to the house.


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## ecr (Jan 4, 2011)

Have to disagree with you fester notching is required here or a post bracket has to be used so beam can rest on top of post. Beam can not be supported by bolts alone. Check out awc.org for their deck code it is pretty much become the standard. It is to irc standards or higher. I am not sure what you think is going to fail with a notched post. All the weight is fully support by the post. It is to code per irc. For good practice I always used grace vycor peel and stick flashing on top of the notch to prevent water intrusion.


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## ecr (Jan 4, 2011)

Here is a link to the awc deck guidelines. Check out section 8 for beam attachments.
http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf


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## BulletHead (Sep 3, 2008)

Thanks for all the info.

My friend doesn't want to add ledger and wants to run joists off of the rim joist of the existing deck, so the joists will run parallel to the house.

So what we did is took off the old 2x8 which was a 2 piece rim joist and using SDS (strong-tie) 3" screws, secured in a full 2x8 as a new ledger board on the existing deck. Used 2 SDS top and bottom spanning 16".

We are using 4x6s as posts (notched) and will add similar bracing as shown in your image ECR, thx.

So my Lj is ~8' and Lj/4 (distance from ledger on existing deck to first post) is also ~8' which is compliant with table 2. But is PT lumber same as Southern Pine?


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## BulletHead (Sep 3, 2008)

ECR, in you last pic, how are those double 2x8s secured to post? bolts or lag screws?


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## ecr (Jan 4, 2011)

Sorry to respond so late. The beams are through bolted with 1/2 galv. Bolts. I would not try to notch a 4x6 only notch 6x6 or larger. Buy the appropriate hardware To mount the beam on top of the post. I will look up a part # for you an post it latter.


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## ecr (Jan 4, 2011)

Simson strong tie # is. ccq3-6sds2.5 you can use sds screws with those also.


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## BulletHead (Sep 3, 2008)

What do you all think about this since I dont have a ledger board for support and relying on old deck, this type of bracing should help. I have the foundation right below the joists that I can use.

Source:
http://www.deckmagazine.com/Images/030_pdb_jan14_tcm122-2109694.pdf


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## ecr (Jan 4, 2011)

Without having the ledger attachment you will have a hinge effect. I have had a local machine shop make me these brackets for freestanding decks. You can have them made out of 1/4" steel.


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## Chamfer (Sep 6, 2014)

This is the last deck we built at work. For the lower second tier that was freestanding we used 6x6 posts notched for a double 2x10 beam, which the 2x8 joists sat on. Beam was bolted to the post with 1/2" bolts, 4 on each post. To attach the joists to the beam we used diamond shaped simpson ties and twist ties on the ends. Our foundation consisted of 24" deep holes 18" wide with concrete footers 12" thick. Concrete was then added the remaining 12" around the posts on top of the slabs. For bracing we used 2x4's with 1/2" bolts, two on both ends connecting to the posts and beam.

All county/city codes are different so be aware. Hope this helps.


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