Concreting the barn

The farm that I purchased was originally used to milk 300 holstein-sized cows, with another 150 cows on the property that weren't being milked.  So my barns at time of purchase were set up to house 450 cows inside a barn for the whole year.  The cows typically wouldn't ever exit a building.

My pig operation wants to provide shelter and labor-saving for the winter months when things aren't growing, but the majority of the time I want the pigs to be outside doing their pig thing.

I have 4 main barns; a 30'x100' birthing shed, a 100'x80' wooden hay barn, a 44'x110' heifer barn, and a 250'x100' main barn.

The big construction project for this spring is putting in a new floor in the 44x110' heifer barn.  for as large a barn as it is, it's pretty much unusable in its current form.

This picture is one reason why.  The floor of this barn is perpetually wet.  Not just damp; streams of water flow across it most of the time.  Next to this barn is a large slab of concrete, and when rain hits it the water flows to the edge of this barn, and then against a 24" concrete wall that was poured along
the edge.  The "easy to do" picture is how they formed up that wall.  The red is the slab, and the black is the wall.  The water flows in the crevice between the wall and the floor, and while the flow is slowed by the wall, that just means that it continues to dribble out for days after it rains.

Had they poured the wall as shown in "the right thing to do" the water would have been mostly prevented from entering the barn in the first place; or if it had it would have been easy to fix.  and much stronger.  The way these knee walls are formed leaves them liable to be knocked free by normal activity - i've broken them free myself.

As it is, to dry out the floor of this barn, I'd either have to put in a drain along the full 110' length (and then figure out somewhere for the drain to empty to!) or I'd have to do something to try to seal the concrete, or both.

The walls that they formed are curbs for pushing manure around, and I really don't need that in my operation.  Maybe a perimeter wall so that i can scrape the barn with a tractor without damaging the walls.  So what I'm going to do is to remove the walls and curbs, and then put a few inches of gravel down, compact that, and then lay a plastic sheet over the whole floor.  Both for vapor barrier and to keep the concrete from getting into the gravel.

The basic plan isn't to try to restrict the flow of the water, it's to give it a place to flow that doesn't affect the use of the barn - basically raise the floor about 8" from where it is now.  As a side benefit I'll also increase the grade (the slope of the floor) so that water drains from the barn more easily when I pressure wash it or clean it.   And finally I'm going to do a trowel-finish, so that there's less texture for the bedding or material to stick to.  It's a little less firm for footing, but every crack and crevice is someplace that is hard, or impossible, to clean, and being able to completely clean animal areas is important for biosecurity reasons.

I've got two contractors coming on saturday to give me estimates, and one on monday.  Curious what they'll quote me for this slab.  it's 5500 or so square feet, 2% slope, trowel finish. about 60 yards of concrete.