Sonotubes

[crashz]

I've used the old style Sonotubes for piers ranging from 4-6 ft without issue. The new ones seem easier to strip. But they always seem to be oblong or out - of - round.

The literature states they are designed to be placed as the form. But I would use 2x4's along the full length, 90 degrees apart, box bracing and then bracing to the floor or surface to support the weight and keep it plumb. So essentially a form within a form.

 

[Larry Caldwell]

I've poured 20' columns using sonotube. If they blow out, they will blow out at the bottom, so pay close attention to the cribbing at the base. The tube will stretch a little, which causes it to float, and once it starts you can't stop it. Don't try to dump it full all at once. Do it in 4' lifts, vibrate, do the next 4', etc. I would recommend using a crane bucket rather than a pumper, because it's slower, or just a couple of healthy hod carriers with buckets on ladders. One column is only 1/3 cubic yard, so a 1/4 yard crane bucket would nearly fill it in one dump. Don't do that. If you use ladders, the bracing has to be strong enough to accommodate that.