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What's the purpose of tubes when pouring piers

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Sep 16, 2013, 12:54 PM
BigManMark
What's the purpose of tubes when pouring piers
Watching DIY network, I notice that when pouring a pier for a deck post or similar, that a tube is often inserted before the concrete is poured.

I just pour the concrete directly into the hole left by the auger or post hole digger. Other than the neat top visible sticking out of the ground, is there a purpose to the tube?

I see the tube and wonder how I'd fill the dirt tightly around it again and that it'd be "tippy". If I pour right into the hole, then the dirt will be tight around the concrete.
Sep 16, 2013, 01:59 PM
redoverfarm
Te tubes are sonotubes. "Sonotubes" are a patent namebrand but others offer the same as Tubular concrete forms. They don't usually set up on top of the ground. A portion is in the excavated hole. Typically they are used to pour piers to a desired heigth. Construction begins on top of them with a fastner suited to your needs. It also allows wood to be elivated above the ground to prevent rot. They are an alternative to laying concrete block piers.
Sep 16, 2013, 02:32 PM
BigManMark
Sure... But why the tube all the way to the bottom of the hole? Why not just fill the hole with concrete without a tube?
Sep 16, 2013, 03:45 PM
Sparky617
You can certainly do that. They also make a base that can go down at the bottom to spread the load out further. I've used them on footers for the last foot or so to give me a finished look above grade. I like to have the concrete come above grade and the wood posts mounted to a post mounting bracket to keep it off the concrete. The posts last longer if they aren't in the ground.


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Sep 16, 2013, 04:32 PM
redoverfarm
quote:
Originally posted by redoverfarm:
Te tubes are sonotubes. "Sonotubes" are a patent namebrand but others offer the same as Tubular concrete forms. They don't usually set up on top of the ground. A portion is in the excavated hole. Typically they are used to pour piers to a desired heigth. Construction begins on top of them with a fastner suited to your needs. It also allows wood to be elivated above the ground to prevent rot. They are an alternative to laying concrete block piers.


That is just to stabilize the tube. It does not go to the bottom. May I ask why you are inquiring or what you intend to do with the sonotubes?
Sep 16, 2013, 05:33 PM
BigManMark
I did what Sparky above said, I used tubes on the last 8 inches or so of the base to make the top neat and pretty. I also figured it would keep dirt from touching the post and prolong the life of the post.

I did this on a backyard pergola.

Detail of post bases

Sep 16, 2013, 05:36 PM
BigManMark
Just do show the finished product.

Finished product