Explain concrete sonotubes to me

[marchanna]

Read thru the posts fairly fast but didn't notice that anyone mentioned what happens if/when the tube itself deteriorates. Not proclaiming a problem with that but just something that probably happens over time.

The tube always deteriorates. Usually only after a couple years. It’s a gradual process and the soil just settles in as it happens. Is a non-issue because the tube is so thin.

 

[/pine]

FWIW...If the top of the piers are larger than whatever is bearing on them...the top of the pier should be slightly canted away from the bearing points to prevent water from laying on top of the pier...

 

[MossRoad]

They also make a finish-free type product that has no lines inside, and a zip cord built into the tube. After the concrete cures, you pull the zip cord and it rips a slit for you. Then remove the tube. No manual cutting required and it leaves a smooth finish VS the more traditional spiral pattern that's seen in the concrete after the regular sonotubes are removed.

 

[MossRoad]

FWIW...If the top of the piers are larger than whatever is bearing on them...the top of the pier should be slightly canted away from the bearing points to prevent water from laying on top of the pier...

Yep. Try and smooth a little raised crown to the top of the concrete so any water wil run off and not puddle.

 

[MossRoad]

The tube will rot away. They can be removed, if desired, by making a slit on two sides, then around at the depth you want to remove it, then peel it off. It's waxy coated inside for easy removal.

 

[MossRoad]

And they make great forms for cat climber/scratching posts, too...

He's so cute!



AHHH, My finger!!!



That's better.

 

[Rustyiron]

This is exactly what I was try to say is the problem I see with putting the tube all the way in. If you dig a hole and put a post in it and fill with dirt it will never be stable. However if you drive the post in which many people are doing here now it seems to work fine.

I took your OP as you wanted to use sonotubes. Sounds like you just need to drill a hole, fill it to a few inches below grade then simply use short pieces of the tube to your desired height above grade, simply as a concrete form for the exposed portion. quick & easy.:thumbsup:

 

[joeu235]

The diameter of the pier has more to do with the weight bearing capacity of the soil than the strength of the concrete.

 

[TractorNH]

In some jurisdictions where the ground is prone to frost, there is also a requirement in the building code where the tubes need to be installed and inspected before the concrete is placed so the inspector can verify the depth of the tube is below the frost line. You can't do that any other way than by using a tube of some sort that can be backfilled after it's installed.

 

[oosik]

View attachment 550747View attachment 550748 These pictures were taken to show the first row of logs on the cabin we built in AK. If you sort of use your imagination - you can see the sonotubes on this end.