Barn Foundation

hismatthew

Hi everyone, I plan on building a fairly small barn, 16x28. I want a dirt floor inside so I do not want a slab. I was thinking I could rent a large ditch witch and basically trench the outline of the barn below the frost line and more or less fill it with gravel then concrete straight into the trench, about 4-6" wide. Then I'd just frame the walls on top of the concrete. Is there a better way or anything crazy about this idea? Thanks for your knowledge and help!

Bondo

Ayuh,.... 4" to 6" sounds mighty skinny to me....

Twice that seems more like it...
'n usually, the footer at the bottom is wider than the foundation's top...

Daniel Holzman

Couple comments. It is not uncommon to use soil as the form for concrete, provided the soil will hold up in place and not slough into the concrete as the concrete cures. Of course, this depends on the soil type. For example, you cannot get an effective form from sand or gravel, they simply slide into the trench. Stiff clay can be effective, and dense glacial till can work also.

The size of the required footing is likely dictated by local building codes. If you do not need a permit, or you do not plan to get a permit, then you should size the footing based on the actual load of the barn and the bearing capacity of the soil, or you can refer to building code and size the footing appropriately based on your soil conditions and code requirements. Six inches wide is about the absolute minimum I have seen for any reasonable building, but of course your local codes may be different.

If you plan to install steel reinforcing, then six inches would be the absolute minimum due to the need for adequate cover over the bars to prevent rusting.

jomama45

All I can say is "Good Luck" in doing what you have planned. The trenching needs to be perfect & smooth to resist frost heave & offer adequate bearing for the walls above. Personally, I'd consider a grade-beam/turned down slab instead.

hismatthew

It would be clay soil and I'd do it in summer when it's dry. The footing would basically support the outside walls, the roof, and a second level that would hold hay. I was also thinking maybe 6x6s in the corner's, buried or mounted on the concrete would be good for support too.

The only problem with the slab is I want animal urine to be able to drain into the floor. Concrete floors are not good for animal health. I suppose I could line the trench with thin plywood or something to frame in the foundation wall so that it stays smooth. Does this sound feasible? It would be worth the sacrifice of some 1/4" plywood for the dirt floor inside. I could even angle it a shade so that I have a pseudo triangular wall.

Thanks for the feedback! I'll take all I can get.

86Sumo

Hey, my first post. Yay.
Ok, why not just dig holes and make it like a pole barn? Cheap and with the post below frost level it won't heave. Use rot resistant wood at ground level and 2x6's horizontal every 2 foot like a ladder and screw some tin on it. It worked for all our barns on the farm. We even used old power poles for the posts on one of them.
Hope that helps.
If not, so much for my first post.
Bob

hismatthew

That is definitely worth considering. One issue is that we want to keep it predator proof. There are a lot of weasels and the like that would dig under the walls. We could trench and bury something cheap to 2 feet or so. I guess it will all depend on code.

86Sumo

Number 2,
Yep, we used chicken wire, run it down in the ground vertical for about a foot and then straight out horizontally away from the building for another foot. Skunks, weasels, and the like will go to a wall and dig straight down and hit the horizontal chicken wire and then stop. The chicken wire did rust after a while, though.
Bob
Yes, check local codes as pole barns may not be legal.

jomama45

"Reading is fundamental"..........

Somehow I missed the part about the dirt floor. I'm thinking the pole barn may be a good option, depending on how much weight you plan to carry outside........