Floating Concrete Pad for 16 x 20 High Wall Barn

[wingnut406]

Hi,

I am building a 16'W x 20'L x 10'H High wall Barn and I am pouring a monolithic floating pad as the foundation. It will be 12" x 12" thick all around perimeter with a 5" thick floor in center. Will use #4 1/2 inch rebar vertically 6 inches in from the edge of concrete forms and 30 inches apart all around perimeter, then running rebar around perimeter 5 inches from the bottom. Then run rebar length and width like a checker board having 30 inch squares, all tied together. I am using 4,000 psi concrete. Is this all sufficient for what I am doing and once I build can I just lag the sill plate down or do I need to set J bolts in concrete before it dries?

Thanks,

Scott

[concretemasonry]

Wingnut -

What part of the world are you in and what is the climate (frost depth?). Very often,even for building as small as 16x20, a different type of support may be better and cheaper in the end.

Your wood sill should be 6" above the finished grade, which requires the floor slab to be about the same.

Often, a stem wall and footing is better and allows to you do the slab for the thickness you want/need and to provide drainage, if necessary.

Dick

[RTF]

As Dick stated above, your soil and climate conditions affect your footing/slab design. In my area we pour mono slabs for projects like yours. Normally we run 2 pieces of #4 rebar tied together every 12" on center placed on chairs,normal clearance is 3" from the soil. You can float in an additional piece of #4 rebar as you pour the top of your footing section. You can use 6x6 welded wire mesh for your slab reinforcement instead of the rebar mat, a 4" slab will be sufficient. You can use a lower psi concrete and save a few bucks. As far as sill anchors you can install anchor bolts as your concrete is setting up or drill the slab later and install anchors, Simpson Strong Tie has several to choose from.