Concrete base

JMER817 · Dec 25, 2019

So prepping for my future Polebarn I had to cut down and remove a dozen or so trees. Had an excavator come out and rip out the stumps. I sifted thru with my box blade and brought in 100yards of bank run fill dirt. The depth of the fill dirt because of the slope ranges from 6” on one end and up to 30” on the other end. I spread it in 2-3 lifts using my Harley rake. My plan was to let it settle over the winter and let the freeze/thaw cycle do its thing. I figured this would be enough compaction before laying the concrete floor. Now I am beginning to second guess myself. Should I have compacted it in multiple layers with a plate compactor? Debating if I need to strip down and re-level but use the compactor. Thoughts?

Jstpssng · Dec 25, 2019

Frost and rain are the best compactors you will get. By spring it will be fine. Are you going to put down foam board before pouring? Aside from the obvious insulating value it will also spread out the weight of the concrete, although I doubt that you would have a problem anyways. Just make sure that the frost is completely out before you start pouring, it can go down a long ways in gravel.

EddieWalker · Dec 25, 2019

Plate compactors are horrible for compacting soil. They are more for compacting a few inches of base for patio pavers.

I would fill up the front bucket with a load of dirt and drive over the pad so my tires covered ever inch of it multiple times. Then I would do that again a few days after it rains. And depending on how hard the pad gets, I might do it again a month or two later after it rains.

RNeumann · Dec 25, 2019

What is bank run fill dirt? The pics show something with organics and maybe clay?

JMER817 · Dec 25, 2019

RNeumann said:
What is bank run fill dirt? The pics show something with organics and maybe clay?

Mixture of small stones, sand, and a little clay. Everyone around me uses it for fill.

JMER817 · Dec 25, 2019

EddieWalker said:
Plate compactors are horrible for compacting soil. They are more for compacting a few inches of base for patio pavers.

I would fill up the front bucket with a load of dirt and drive over the pad so my tires covered ever inch of it multiple times. Then I would do that again a few days after it rains. And depending on how hard the pad gets, I might do it again a month or two later after it rains.

I see that I can rent 450lb plate compactor which states can compact up to 16”. If I decided to rent one this would be this larger unit. Most other compactors are around the 150lb range.

RNeumann · Dec 25, 2019

JMER817 said:
Mixture of small stones, sand, and a little clay. Everyone around me uses it for fill.

That should lay in fine. The footings for the poles would get into the native soil below. The flat work should be over a few inches of sand- I’d put the sand in right before I did the flat work.

I don’t think the imported soil will benefit from re-laying it in smaller lifts. Sand and small stone don’t get much tighter with added weight and or moisture.

s219 · Dec 25, 2019

If you did it in 2-3" lifts and then drove over each layer to compact it, I think you'll be fine. That's what I did for my barn 5 years ago (using a base of #3 gravel with layers of compactable sand/clay fill). Have not seen any settling issues at all.

Egon · Dec 26, 2019

With the amount of granular material your’e fill contains a small smooth drum vibratory would be ideal. The plate compactor also works. Both take a little time. Especially the plate compactor. As the clay content rises toothed compactors work better.