OT- Pour a slab over mesquite stumps?

I have around 12 mesquite trees in the spot that I've chosen to build my barn/shop.

I was planning on just cutting them to the ground and putting my stump killer on the stumps and covering everything with the base that I'm going to spread with my tractor.

My question is, should I get a dozer on the site and have the stumps ripped out?

Once I cut these stumps I'm figuring to have about a 8" to a foot of base over them to pour the slab on.

Maybe I'm over thinking it, but figured I'd ask.

I would think that as the stumps rot away they would leave voids that would weaken the base your floor is sitting on. Just my opinion.

Get rid of them. You also have to strip off any topsoil or other organic matter and compact the subgrade anyway. Or you can just dump the fill on the ground, pour the slab, and then live with the cracked slab under your shed.

The only alternative would be to pour a thicker reinforced slab. Then you might still have uneven settling and end up with a slopping floor.

Areo

Well, not mesquite, but I had a willow stump burried in the yard. Several years ago, am still dragging in fill dirt every spring, to fill in the sinkhole.

I am not as knowledgable as some "cement" guys but I can tell you that the most important part of a concrete job is in preparing for it. The subsoil and your tree roots should be removed and gravel leveled in to desired grade,then the gravel should be packed down. You can use water to settle the gravel,or pack with a packer you can rent. If you use a water sprinkler to settle the gravel give it a few days to dry out after.When your slab is pured saw cut it in 8'squares and if there is any shifting it will crack along the saw cuts and not affect the appearance of your floor. We rent a diamond bladed saw from the local lumber yard,it works well and is easy to use,just chalk line where you want your cuts and follow the line with the saw,you only need to cut down about an inch. When I built my shop I used an old skill saw with a masonary blade..the dust was a bugger but in that first year the floor cracked right along the saw cuts and my floor still looks good. You can run a bead of chaulking along your cuts to the level of the rest of the floor,it keeps dirt out and the floor is easy to sweep or wash,but the floor will crack along those lines if you have frost ar any shift in the base..well worth the money to do the sawcuts..but you have to prepare your base for sure..good luck with your shop and you won't be disappointed for doing the extra work in preping.

Not leaving organics that can/will decompose
underneath is one of the first rules a concrete man
learns. Too much water and over mixing would be also
in the top five.

I agree with the others - it's best to get them out, but then you have the holes to deal with. Gotta fill and compact the holes and the rest of the base in layers for the best results. You could also bridge over the stumps by thickening the slab and using a couple of properly placed layers of rebars, but I personally would want them out.