Bubba Foundation Prep for a Pole Barn

I'm putting up a small pole barn, 28x32. The site is on an incline -- about 2 feet lower on one side ( so ~7% grade). A friend is going to level the site with a bulldozer. He has several years experience in a former life so I think he'll do fine. I intend to put down several inches of stone and then pour a concrete pad on top -- so no footers. Question is how much stone should I put down? How much is too much? -thanks.

I would have the pad set on pylons anytime that much fill, my garage is that way.

Bret ,We usually y put about 4 inches and compact it. Are you
doing a pole barn or building off the slab? I helped with a
monolithic slab a couple weeks ago the outside perimeter is
about 16 inches thick and the center was 6 inches. If he?s
cutting out a level area are you having to build back up?

I would make sure the cut made by the operator was to undisturbed earth over the entire "floor" this includes top soil at
the lowest point. A laser level made by Bosch is cheap, and easy to use. Once flat, I would ditch the high side/s at least
20 inches deep and put in slotted tube covered with river gravel without fines. I would then put barrier cloth over the
gravel and fill with more gravel and finish as it is intended to look, keeping porosity in mind to keep moisture/liquid water
from flowing in. Inside I would put down heavy poly sheeting to lessen the inflow of moisture from the sub soil covered with
pit run 3/4" and smaller (many names, need 30% fines to solidify) about 3 or 4 inches, and compact it. Concrete with
Fibermesh in defined pads of 16' square or so. Finish with a slope to the door if only vehicle melt off will happen, or if
you intend to use water in it, floor drains. Jim

There's a reason they call the footer under the edges of a slab a "rat wall" but
proper site prep like the other guys suggest should minimize rodent intrusion.

Greg - I want to get down to undisturbed earth. Then put down stone and frame & pour a pad. Can I put 4 inches of stone and compact, then build up more stone and compact? Or could I put a foot of stone in combination with pylons underneath?

David - what do you think would be the spacing/how many pylons in that size slab?

Jim - Great idea to get a laser level. I'll keep the floor level with no drains. Thanks also for the other details, I may leave this job to a professional. lol

Steve - that we be good, we sure have plenty of them around.

D9 you get much frost and heaving in your location ? I think I would want
some type of footer. Could be poured monolithic below the frost line if
you live in an area that gets a decent amount of frost. My current garage/
shop is 28x24 with no footer as far as I know. Built by previous owner.
It's holding up ok but heaves with frost. I also have a problem with
critters burrowing under the slab. Good place for mice, rats, snakes
even chipmunks and squirrels. I would never spend the money to put up a
building without a footer. Just my opinion. And your original question.
Any amount of stone is ok as long as it's properly compacted. I build
roads ect for a living and 12 inches of stone is common. Compacted well.
Not with a lawn roller. A big heavy roller.

I think the pylons are 10' apart, go down below frost and have rebar down them, then radiating out into floor.

Brett , You can compact in lifts of 4-6 inches. Every site is
different the last one we carved out of the side hill with the
excavator and hauled the material away so All was on solid
ground. No pictures so it didn?t happen! Lol my battery is shot
on my phone so I leave it home. Doesn?t work most times up
in these hills anyway. On the job we did for Whitman lumber
they had soil tests done and the Jumping Jack ramp worked
the best. We even had a large vibratory roller and where he
couldn?t get the Jumping Jack was used in lifts. On that job we
poured at least 1500 yards for their kilns and dryer buildings.

Well, don't do like my BIL did. He paid some guy with a bobcat to prepare his polebarn site on the side of the hill. All the guy did was to scrape off the topsoil. I told my BIL that it was no good, but I'm guessing he didn't want to pay what it would cost for a proper site prep. When we set the posts, the low side was like two feet lower than the high side! He had to splice some extra length on to one of the posts just so he had something to nail the girders to. There was a foot gap under the rim boards he had to close off with lumber. He never did bring in any fill to level it off. He would have water standing anytime it rained. He eventually sold the property; I sure the new owners have had fun trying to straighten that mess out.

When I built my shop, I picked a fairly high spot and had sandy fill brought in. I compacted the fill as best I could with my tractor and a vibratory compactor. It's been almost twenty years since I poured the floor, and there's not a single crack in it. I have good drainage on three sides and OK drainage on the door side. Time and money spent properly preparing your building site will pay off many times over.

It sounds like you're going to put brackets on the floor and attach your posts to them. That's OK, but those posts have a LOT of weight on them and the floor has to support them if you don't make footings. Do the math on how many pounds of roofing each post has to support and I think you'll want footings.

Make sure you put a heavy vapor barrier under the concrete.

If you live in a northern climate you might want to also insulate
under the concrete.

Paul

I hauled in about 40 ton from an old
driveway, #2 & #8

White rock.
I first removed top layer of sod, 5 dump
trailer loads. Used disk on Jubilee to
break up sod.
Then I leveled dirt before bring in the
gravel.

Then I used some top soil and blended it
in with the gravel. I had my building
site leveled about 6 weeks before



Construction. I used my Dewalt rotating
laser to get it level. Because a quarter
inch of concrete is a cubic yard $100. So
accurate level ground pays dividends.
Between layers of rock, dirt and rain, I
rolled it with you 5000# roller.
Once it dried it turned into concrete.

I learned not to get in a rush to put
down concrete. We got about 5 inches of
rain and got a lot of settling around
posts. So I added more gravel and dirt.
Concrete finisher packed it in before
pouring.







21 yards later, 5 gallons of cure and
seal. I have a beautiful floor, 5.5
inches thick and contrary to some on YT,
it hasn't cracked, settled, or sank to
China. I've used this finisher on other
jobs. He's a professional, Concrete
finishing is all he's done and he is
about to retire.
I did all the excavation work with
Jubilee and Terramite and dump trailer
was very handy.


The thing I love are the sky lights under the eves. Highly recommend.


V

(quoted from post at 09:12:35 04/25/20) A laser level made by Bosch is cheap, and easy to use.

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Jim, which Bosch is the cheap one?

I bought 8 mil plastic from Amazon for half price at menards.

I would recommend an 18" rat wall to keep critters from burrowing under. That's what I did on both of mine and they eventually gave up trying.

(quoted from post at 08:00:10 04/26/20) I would recommend an 18" rat wall to keep critters from burrowing under. That's what I did on both of mine and they eventually gave up trying.<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto2857.jpg">

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I don't think I have a rodent problem with all of the hawks, owls, foxes, and bobcats. But there are norway rats around here. I think they are usually after food sources or heated living spaces. I have seen rats dig under pole barns with dirt floors but not under concrete with building stone. To me the labor and expense of a rat wall would not be worth it. Easier to inspect the outside of a building and poison and/or fill their holes? I have groundhogs too, but they mostly stay away from my buildings.