I am building a 12 x 12 free standing deck around a swimming pool, on un-level ground. I prefer not to use precast post supports, or make a floating deck, with precast post supports. The side of the deck next to the pool will be about 4 feet high, and the back edge of the deck (furthest away from the pool) will be about 1 foot off the ground.

My problem deals with the post supports. I figure on digging post holes about 2 ½ feet deep (this is below the frost line) for concrete post supports. My question is, should I put the treated posts on top of the concrete, or should I put the posts in the hole and then pour the concrete around them?

I figure the posts that are in to the bottom of the hole will be incredible stable, but subject to rotting. The posts on top of the concrete pillar, will not rot easily, but will not be very stable. The posts on top of the concrete will also be easy to replace 20 years from now. Is there another method for constructing the posts/supports, that will give me the support I need without the rotting problem.

I also thought about first putting a coating of tar on the buried portion of the treated post to keep them from rotting.
Thanks
mscany42

 

Post connected to concrete using an approved metal connector are quite stable. IMO this is the best option.

Another option is to dig a hole an drop a concrete "cookie" like they use for pole sheds in the bottom. Then put posts treated for direct ground contact on top of the cookie and back fill. This is still better then posts encased in concrete.

 

If you plan to live there forever, use 6 x 6 PT posts rigidly attached to galvanized steel (properly-anchored) brackets, on top of poured concrete footings. If you're just flipping the place, go with untreated 4 x 4s embedded in concrete.

And welcome to the site. It's a great place to learn.

 

I would not use untreated posts!! It could prove difficult to sell a home that had a deck with untreated posts..... and I doubt the PT posts would cost much if any more. I also would recommend placing the posts on top of the concrete. IMO the only time to bury a post is when building a fence

 

I think you can go either way but be sure to check your local building code to see what sort of deck support requirements it might have.

If you opt to bury the posts make sure to buy ground contact treated wood. Big box stores don't normally carry that but they can special order it.

 

what do you mean by a concrete cookie? is that just a concrete pad at the bottom of the hole?
and thank you everyone for the helpful tips.

 

Some more information. This is WV and I am out in the contry. There are no building codes !!!!!. Which makes for some shoddy houses. .

Anyway, I have talked with several people in the area, and they said since it is a free standing deck that the conectors embeded in the concrete would not be stable, and that the deck would start to lean. So my question is which connectors to use that are stable enough. By the way, I dont mind using 4x4/s or 6x6/s.

 

Yes......a round pre-cast concrete pad......12" dia. x 4" thick.....placed at the bottom of the hole......pressure treated post sits on top of pad then back-filled with dirt.....basically acts as a footing.

Not necessarily......the results are always dependent on how well the deck is built. Proper construction methods using correct fasteners and diagonal bracing would ensure the deck does not lean. Think of it as a well built table.....if it is solidly constructed.....it will not lean regardless if it is fastened into the ground.


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Thanks Halton for covering "cookies"

I like to use any of these post connectors: ABA/ABU/ABW Adjustable and Standoff Post Bases

 

I knew what they were because I used them myself.....lol

Found a couple of pics from my deck project.....looks like they were about 6" thick.....(50" deep hole)


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