# 6x6 deck posts to concrete slab



## csiryan (Nov 13, 2009)

Was wondering if it would be OK to attach a support post to an existing concrete slab using some sort of bracket?


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## Scuba_Dave (Jan 16, 2009)

Yes - simpons makes a support bracket to drill & bolt to the concrete slab
But in most cases you need more support then the slab offers
Here I needed an almost 4' concrete support in the ground


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## 12penny (Nov 21, 2008)

Scubas right. In theory, yes... you can attach it to a slab. In practice, you probably cant because of load issues.


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## csiryan (Nov 13, 2009)

*OK Thanks!*

Thanks for your replies...I have about a 6" thick slab to work with. I found a bracket at Lowes for the exact application and I think will do. Not the most attractive thing in the world, but will do.
Ryan


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## 12penny (Nov 21, 2008)

csiryan...I dont think you got what we said. 
You can attach a 6x6 to anything.
But you cant support a deck with a 6" concrete slab. 
At least not here in the northeast.


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## Scuba_Dave (Jan 16, 2009)

If you are putting a deck above this you will probably crack the slab if too many people are on the deck & depending upon the size
And if the deck is attached to the house you have to have support to the same frost depth as the house

If you are putting a roof over the slab it maybe OK
Depends upon span & lumber used


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## csiryan (Nov 13, 2009)

*OK, I live outside Atlanta.*

Why would a slab that thick not be good enough? The only alternative would be to cut the slab out, which would be less than desirable.


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## COLDIRON (Mar 15, 2009)

csiryan said:


> Why would a slab that thick not be good enough? The only alternative would be to cut the slab out, which would be less than desirable.


 
Depends what part of the country your from and the codes.


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## Scuba_Dave (Jan 16, 2009)

csiryan said:


> Why would a slab that thick not be good enough? The only alternative would be to cut the slab out, which would be less than desirable.


Where are you located?...ah you put Atlanta in as location
What are you building...roof or deck ?


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## stadry (Jun 20, 2009)

depends on how FAR outside of atlanta,,, if you're like me in marietta, probably not a problem,,, if you're 1,500m north of atlanta, problem :yes: down here our footers're only 1' below grade since we don't have snowload or frost w/which to contend,,, however, we DO have windload uplift issues,,, good luck !


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## Thurman (Feb 9, 2009)

csiryan: There are many people on here that offer good advice backed by proper education and experience. Scuba_Davd, and 12penny, happen to be two of them, SULTINI I just don't happen to recognize (sorry). Give more details of your project and listen to them. It does sound as if you are planning a second story deck or roof. Personnally, I do think a 6" slab would hold up a 6x6 post, just not a deck or roof. Good Luck, David


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## [email protected] (Jul 26, 2019)

Hi Everyone, are you guys saying that fastening a 6x6 post to a concrete slab is okay as long as it’s protected from rain and snow? Would that mean that if I installed a 6x6 inside a shed, it would be okay? 
I want to be sure that I understand before I proceed. BTW, I want add this support because I intend to put some spare lumber, within reason (200 x 250 lbs. max), up into the rafters of my shed for storage, and this post will beef up the support.


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## carpdad (Oct 11, 2010)

Probably fine but if the concrete slab begins to crack there then hindsight would say we were wrong.:smile: Also you don't need 6x6. Single 2x4 will be fine although doubling is best. For a shed, do you have ceiling joists? You also can double the joists for holding little more weights. Depends on the construction.


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## [email protected] (Jul 26, 2019)

Hi carpdad, 
thanks for your reply it was helpful. You're right, I don't need a 6x6, so I will likely use a 4x4. Also, I am going to double the ceiling joists just to be sure that I don't run into problems. The concrete floor of this shed is approx. 9" deep, reinforced concrete. Hopefully, cracking won't be an issue, especially since the reinforced ceiling joists are there. Did I forget anything?


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## The Manor Manor (Nov 12, 2020)

Thanks to all those who contributed to the thread above. I'd like to pile on with a question about installing a post on an existing slab. The question is, will a 2-foot deep, 1-foot wide foundation footer serve as an adequate base for deck posts? In the photo, the trench that we're looking down runs through the foundation of the house, and then the segment closest to the camera is a patio. So the deck posts would be attached to the concrete immediately over the foundation footer. This is Austin, so no issues with frost heaves.


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## Nealtw (Jun 22, 2017)

The Manor Manor said:


> Thanks to all those who contributed to the thread above. I'd like to pile on with a question about installing a post on an existing slab. The question is, will a 2-foot deep, 1-foot wide foundation footer serve as an adequate base for deck posts? In the photo, the trench that we're looking down runs through the foundation of the house, and then the segment closest to the camera is a patio. So the deck posts would be attached to the concrete immediately over the foundation footer. This is Austin, so no issues with frost heaves.
> 
> View attachment 635813


  You could not do better than what you have for a deck footer


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## The Manor Manor (Nov 12, 2020)

Nealtw said:


> You could not do better than what you have for a deck footer


Many thanks!


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