Core fill for base

How much concrete is needed to fill just the cores in the base with the rebar?

Hi Gianni! When I built my base I had 60 lb sacks of 4,000 psi concrete. My recollection is that it took about ¾ of a sack to fill a five course core. I decided to anchor the first course at the four rebar points, and then to fill the cores once all 5 courses were laid. The cores should line up if you do it according to plan. The advantage is that each core ends up with a single very strong pillar of concrete anchoring it.

Hope this helps!

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It’s been awhile. I filled all of the holes in the cinder blocks. This includes the gap between each one. I built my base a little bigger than the plans. So one row had 10 cinder blocks. And if I recall right it took 3 bags per row. 4000 psi. 5 rows that is 15 bags.

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Thanks, that’s helpful. So I plan on doing just the cores that have rebar and figured 8-10 of the 60lb bags.