Need help answering Q: How much concrete is needed

[oldpops]

Hello all! First let me say that I am very appreciative for all the help I have received here before (not only that, but for a disabled senior stuck at home: getting reply's here reminds of the days of my youth waiting for the toy prize to come in the mail! - YES, I am that old). Anyway, My wife and I toyed with the idea of building 3 solid-concrete concrete columns (all concrete - no CMU blocks). The first column is 2 feet wide x 2 feet long by 5 feet tall. Columns two and three would both be 1 foot wide X 1 foot long by 5 feet tall. We would also need to put footers in for both of them. Could folks here let me know how many 80 or 90 pound bags of pre-mixed concrete would be needed (for the 3 columns and the footers)?

There is a jack-of-all trades person we know desperate for work, who said it would be cheaper, and stronger, to build the columns completely out of concrete alone (rather than CMU blocks). When the guy told us how many bags of concrete he would need, it seemed excessive, and if he's correct, than maybe it would be smarter & cheaper to have a concrete truck deliver it. We have the rebar and wood to make frames, but not the concrete. I'm not a concrete guy so I defer to people here who know more. If I knew what the total amount of concrete needed was/is needed in bags, and if I can convert it to cubic yards, maybe it would be better to have it delivered.

Thanks in advance to all who offer help, advice and suggestions.

 

[Rst277]

The bags of concrete have the volume in cubic feet on the bag. 2x2x5 is 20 cubic feet, 1x1x5 is 5 cubic feet for 25 cubic feet in total. A cubic yard is 3x3x3 = 27 cubic feet. Depending on your footers a yard may be enough but no concrete truck will deliver 1 yard. Divide your requirements by the number on the bag and you will know how many bags you'll need if you go that route. If you buy 50 pound bags, you'll need about 70 of them....... Do these columns NEED to be made out of concrete? Could they be made out of something else that looks like concrete?

 

[Sherk]

You don't say how big the footers need to be, but columns alone is 30 cubic feet (or 1.11 cubic yards). There's a handy calculator at:

Concrete Calculator - How Much Do I Need? (Bags & Yards) - Concrete Network

Calculate how much concrete you need in cubic yards, meters or bags with our accurate, contractor-trusted concrete calculator. Easy to use on any device.

www.concretenetwork.com

Some places have a tow behind rentable cart that you can get that is about a cubic yard, that's probably the better bet. Even if you need 2.

 

[ConCretin]

Including modest footings under the piers, you'll need about 1.75 cy or eighty 80 lb bags.

Check to see if there is a ready mix company with a volumetric mixer in your area. This is a concrete truck that dispenses concrete in whatever quantity is required and caters to home owners.

You'd still need a concrete footer under masonry piers. A concrete pier is generally stronger than a masonry one but under most circumstances a masonry pier is plenty strong enough. It might just come down to the skills (hopefully) of your guy and what he's most comfortable with.

 

[Joemctag]

Depends what you’re supporting. If you build them out of block (CMU). 24” x 24” is (4) 16” long ( 15-3/8”) in a square with about an 8”x 8” space in the center, where a few 3/8” or 1/2” rebars embedded or epoxied into the footing could run vertical and be grouted in (use bagged concrete). Set anchors in wet concrete at top of column for whatever it supports.
Just try to make sure the guy can build block piers and make them look good. Think I’d get a small-time masonry contractor if you got any doubts. He can fill the block, also.
Good luck!