How level is level?

[wedge40]

Got the shell of the barn done last fall, and now I'd like to get it ready for cement. I plan on putting in insulation, rebar and pex for heat at somepoint.
My main question right now is how level is level? Do I need to get it within 1" all around? I have to remove some of the dirt so I can replace with at least 1" of packed gravel.
On the horizontal I'm going to put 2" of XPS and on the vertical the same. Which is better for the vertical, inside the perimeter or outside?

Wedge

[wedge40]

Sorry this was suppose to be in the Projects forum.

Wedge

[RaydaKub]

I don't know where you live, but if you are going to heat the floor, did you put down some insulation first so the sand underneath doesn't just become a big heat sink?

[wedge40]

I don't know where you live, but if you are going to heat the floor, did you put down some insulation first so the sand underneath doesn't just become a big heat sink?

Please re-read the original post.
I have 2" of xps horizontal under the slab and another 2" of XPS around the perimeter.

Wedge

[jenkinsph]

I would put the XPS on the outside of the form.
Grading for a slab I usually get within 1/4" of level after compacting.
For the engineered fill layer I like a minimum of 4 inches firmly packed.


good luck with your project.

[MHarryE]

I've had my floor (30 x 45) level within 1/4", then went with 2" below and 2" inside the forms. I think the only problem you will have with level within 1" is the amount of concrete as a margin. We gave ourself a very small margin and that small margin was about what was left after the pour, but it was a lot of work to get the base so level. Now I am hoping for a bumper crop this fall so I can finish the insulation and heat it because my welders and torches got moved out of our floor heated garage into this building. We built the garage 10 years ago and only used a thin roll insulation and didn't level it as well. No real problem but wish we had used the extruded foam instead.

[MasseyWV]

For an absolute perfectionist, level is within .000000000000000000001 microns of zero inches, but for the rest of us a quarter inch should suffice. At least that's what I consider acceptable for most wood frame structures I've built.