# What would be the best way to strengthen my 4x4 deck posts?



## bpayne77 (Mar 27, 2009)

I have a PT wood deck with 4x4 posts that run from foundation to top of railing. Unfortunately the contractor "let in" a 2x12 beam into the side of all the 4x4's which reduced the actual width to 2" (3.5" -1.5"). This 2" is responsible for resisting the lateral movement of any pressure placed on the rail. Needless to say...its wobbly. Does anyone have any suggestions to strengthen the post without having to scab another member to the outside of the 4x4?


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## Scuba_Dave (Jan 16, 2009)

That's a pretty standard way of building a deck
I have thru bolts holding mine together - very tight
How is every thing held together?

Metal brackets may be an option to strengthen & tighten everything up. My posts have wrap around metal brackets which are then bolted to the 2x12 deck "fascia" board

I had to go back around & re-tighten the year after I built my deck
Wood does shrink - so that may be the problem


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## bpayne77 (Mar 27, 2009)

Everything is nailed.

4x4 has 2x12 notched in with another 2x12 fascia. there is a 2x2 stop holding the 2x joists rather than joist hangers. there is also a 2x4 scabbed to the front of the 4x4 that "supports" the facia.


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## Scuba_Dave (Jan 16, 2009)

Nails won't do it long term
I have thru bolts & lag bolts that hold everything together
I don't have any pics

The 2x2 stop should work for support, I like joist hangers
The joist hangers help hold everything together
I also went 12" on center instead of 16" - I wanted the deck as strong as possible

I think if you put some lag bolts or thru bolts in that would teighten everything up


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## bpayne77 (Mar 27, 2009)

thx for the suggestion, but I don't think bolting or lag screws is going to help....the deck is stable. What is not is the portion of each post above the surface of the deck because the post was cut to recieve the beam below. I have a hinge condition that is relying on the ability of 2" of old wood to resist the bending moment of force placed against the rail 3' above. Preferably I would of had 3.5", but I don't. There is nothing but deck boards above the location where the post was notched, thus I have nothing to bolt the upper portion of the post to.


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## jogr (Jul 24, 2007)

If you screw/nail on a metal strap across the cut that should stop it from hinging outward.


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## jcalvin (Feb 6, 2008)

As far as a 4x4 goes, that is about as stable as it gets. The only other way to build the deck would be to fasten the 4x4 on the deck directly. Bad wobbly in the best situations. You can most likely tighten it up by bolting the 4x4 with a bolt and nut not a lag bolt through the thin section of the 4x4. Your only other choice is to replace the 4x4 with a 6x6. Not an easy job but not impossible.


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## bpayne77 (Mar 27, 2009)

My thoughts had been either the strap (but in my case the strap would go under the facsia since the notch is on the "exterior" side of the 4x4

or

Build a bench between two of the posts that would allow me to brace the post to the joists.


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## 4just1don (Jun 13, 2008)

I think the bench is the best answer. IF you dont have small kids that can climb on and fall over the top. How high off the ground is the deck level?? OR can you put like a trellace above preventing such falls?? Another idea is a huge chunk of angle iron at least 3" on both sides reinforcing the cut area,,,maybe a foot below and a foot above, with a shorter one for the back side(one on top,one on bottom part),then bolted together to sandwich your 4X4. As said otherwise 6X6 is only other option


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## bpayne77 (Mar 27, 2009)

In fact my deck is only 24 inches off the ground, which caused me to seriously consider just chopping off the post at the height of the deck and removing the railing alltogether. However, my wife vetoed that!


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## Scuba_Dave (Jan 16, 2009)

The bench is a good idea
If my deck was bigger I planned on building in benches


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## rahfiki (Jun 23, 2009)

I build this way...if it needs to be notched...only a 4x6 or 6x6. Otherwise the lateral strength is gone.

Not what you want to hear I assume, but it would be possible (I assume without seeing it, hard to say for sure). Replace the posts with 4x6 or 6x6 and notch them.

Oh ya like they say...bolts, not lag.


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## designseeker (Jun 23, 2009)

I used to put on deck drawings "do not notch posts" but it pushes
out the post so far and no one was doing it anyway. 

Normally, the 2" of wood left should be enough for a guardrail to be rigid.
However, since it is not, I would sister with 3/8" lag bolts a 2'0" long 2"x2"x3/16" steel angle over the notch area. That should make it
plenty rigid. Might not look so pretty tho. If one is not enough, use 2, one on ea corner of the post
http://www.westchester-architects.com


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## Maintenance 6 (Feb 26, 2008)

Have you thought about strengthening the top rail so it disperses the lateral load over several posts?


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## jaros bros. (Jan 16, 2009)

The posts should not be notched as it seriously weakens the posts. The PT posts are allow to have quite a bit of angled grain in them and by notching it could be a serious safety hazard. Inspectors will call you out on it. It's better to drop them through the decking and bolt them solidly. In your situation, the best move would be to remove them and replace them. There's not a fix that's going to look nice and work because the damage has already been done.


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