Deck post Questions.

[6togo]

So I'm a contractor of 30 years and I have built many decks typically digging holes pouring concrete in the bottom or cinder blocks. Sit the posts on that and fill with concrete. Never any real issues too date now I'm building a new deck for a buddy which is getting inspected and code now states no concrete around posts.
That's nothing real new but it poses some questions. The 3 methods are 1-fill the entire 24" dia. hole with concrete and set post on bracket. 2-fill 12" thick base in hole 24" dia. with concrete then add concrete pier to surface and use bracket. 3-pour 12" thick base footer 24" dia. and sit post on bracket then backfill.

We chose option 3 but my concern is mostly the post bracket they are 1" tall galv. steel which will rot away with time. Second concern is post rot should I coat the post with roof coating or such? Backfill with stone after setting the posts?
I'm basically wonder what the best option here is sitting posts on footings underground?
I did chat with Simpson and none of there brackets even SS are tested or rated for underground use.

 

[oldcarpenter]

If you install it with the Simpson post base exposed it can always be somewhat easily replaced. Everything rots in time, post or base.


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[The Cobbler]

here we pour the concrete min 6" above grade, set post brackets , keeps the wood out of the ground contact

 

[ItsNemo]

here we pour the concrete min 6" above grade, set post brackets , keeps the wood out of the ground contact

Yup this, concrete pier in the ground and a little above...post base either a rebar like one you put in the wet concrete or drill and epoxy in some all thread after and bolt to a saddle. Keeps the wood out of contact with the moisture.

 

[Dustball]

Bell the footing at the bottom, use a concrete form tube to bring it up to above the surface.

 

[Stuart in MN]

Pour concrete up to grade level, then set a pier block or deck block on top of the wet concrete so it will bond to the footing. When it all dries, mount the post to that. They should be available at any big box store.

 

[mike93lx]

Pour concrete up to grade level, then set a pier block or deck block on top of the wet concrete so it will bond to the footing. When it all dries, mount the post to that. They should be available at any big box store.

why would you do this instead of just extending a tube above grade? no way the connection will be as strong.

 

[ItsNemo]

why would you do this instead of just extending a tube above grade? no way the connection will be as strong.

Agreed....not a good idea unless you pin them together.

I actually put a couple sticks of rebar in my deck piers and cut them off flush with the surface after the concrete cured. I overdo everything lol

 

[mike93lx]

Agreed....not a good idea unless you pin them together.

I actually put a couple sticks of rebar in my deck piers and cut them off flush with the surface after the concrete cured. I overdo everything lol

Running rebar outside of the pier will just draw moisture and corrosion into the concrete. A cage in the pier then a separate bracket for the post is best, AFAIK.

 

[ItsNemo]

Running rebar outside of the pier will just draw moisture and corrosion into the concrete. A cage in the pier then a separate bracket for the post is best, AFAIK.

The saddle covers them and I threw some sill gasket under the saddle, so should stay pretty dry on those ends anyway, not too worried about it...by the time rust is a problem I'll be dead lol

 

[K'ledgeBldr]

Top of the pier should be above finished grade and have a slight slope to the edge so water does not accumulate on the pier. The mounting hardware would mount to the pier's high point in the center.

None of this should be buried. When the posts are cut, the ends should be brushed with copper-green wood preservative- just in case the factory preservative didn't penetrate all the way through. Connect the post to the connector with structural screws- not nails.

 

[3onthetree]

I have built many decks typically digging holes pouring concrete in the bottom or cinder blocks.

We chose option 3-pour 12" thick base footer 24" dia. and sit post on bracket then backfill.

I'm not sure how you can either place the bracket in the right spot or attach the post to a pre-anchored bracket if the depth of your footing is deeper than your elbow. And pushing dirt in laying on the ground to reach a deep footing. Also, even though the bracket keeps a gap under the post, you could have enough water sitting on top of the footing rotting out the post. Wrapping it with a membrane or coating helps, but may not be a long-term solution either (wood will have moisture content and absorb more above ground, but the wrap will hold it in).

A better method is to pour a pier to above grade. Easy to string the brackets square and level. Sloped wash on top of the pier. At some point, a post will be replaced, and it is much easier to do above grade.

No offense, but hearing you put CMU down there (assuming laying flat, which has no structural value and how do you fill the cores sideways), maybe it could help to refresh or reaffirm some methods with current standards. Take a look at American Wood Council's Wood Deck Construction Guide DCA6. Footings start page 11 but some framing detail requirements have also changed in the last handful of years.

BTW for other replies posts need to be attached at the foundation for lateral movement. And rebar should never be exposed, so unless it's hermetically sealed, putting a hat on it doesn't keep oxygen+air moisture away.

 

[Skiff Builder]

So I'm a contractor of 30 years and I have built many decks typically digging holes pouring concrete in the bottom or cinder blocks. Sit the posts on that and fill with concrete. Never any real issues too date now I'm building a new deck for a buddy which is getting inspected and code now states no concrete around posts.
That's nothing real new but it poses some questions. The 3 methods are 1-fill the entire 24" dia. hole with concrete and set post on bracket. 2-fill 12" thick base in hole 24" dia. with concrete then add concrete pier to surface and use bracket. 3-pour 12" thick base footer 24" dia. and sit post on bracket then backfill.

We chose option 3 but my concern is mostly the post bracket they are 1" tall galv. steel which will rot away with time. Second concern is post rot should I coat the post with roof coating or such? Backfill with stone after setting the posts?
I'm basically wonder what the best option here is sitting posts on footings underground?
I did chat with Simpson and none of there brackets even SS are tested or rated for underground use.

6,
How many footings are you doing and how deep do the holes have to be?
Skiff

 

[6togo]

I used 4" cap blocks not CMU's but we have decided to fill all holes to the top of grade then sit the brackets on that. Just a bit more concrete but problem solved and you can still access the brackets and posts if something happens.