Getting land ready to build a shop. brought down 5 large oaks (15-24") and am in the process of grubbing the stumps with my Kubota & BH. My question is this: I will be pouring a floor in the finished pole building. I know I need to get the stumps out, but how much root should go too?
I don't want to leave any big roots but how small should I be concerned with?
You should never pour concrete on top soil or even subsoil that contains a lot of organics. The correct method would be to excavate the organic laden soil & bring in clean fill that can be uniformly compacted to spec.
That being said, pull the stump & the huge roots. Forget about the smaller stuff.
Make sure you use wire & rebar as appropriate & tell your cement supplier to add some reinforcement fiber to the mix. You'll be fine.
As an aside, I worked for a builder on Long Island who dug footers in the fall & poured his slabs in the winter & framed in the warm months. He poured right on the frozen ground which was heaved up at least a foot. Guess what????? In the summer the ground went down & many areas under the slab had a foot of hollow space!
Hard to believe, I know but that's what happened. Oftentimes, the copper pipes for the baseboard heating that were set in the ground during the pour would fall into the hollow space & we'd have to chop a hole in the middle of a room, crawl UNDER the slab, find the pipe, & push it back up through the slab for the plumbers.
Of course none of this is "right" but as far as I know none of these floors has ever caved in.
The moral of the story here is, a couple of roots probably will not be an issue but please, don't pour on frozen earth.