Floating slab or footings?

[Laredo]

Looking for input / thoughts from concrete experts....did some searching but coming up with a contradicting opinions.

Still in planning / budgeting phase of 2 car detached in Minnesota.
1) Is there a "rule of thumb" regarding how big requires foots vs floating slab?
2) Can I put a 2-post lift on a floating slab?

 

[Jose G]

2 post lift require normally at least 4" of concrete.
keep in mind there are 2 types of concrete... the ones that are cracked and the ones that are gonna crack

 

[K13]

Around here building codes regulate #1

 

[Notch1988]

I did a 24x40 floating slab on my last garage. It was an engineered slab with a thickened edge. I installed a two post as well. After 7 years I had two hair line cracks that I had to point out to people. My next 24x30 will be done the same way.

 

[bczygan]

Check local practice and code. Then look at the loads that will be imposed. Check soils and subsurface conditions and plan drainage.

 

[Grayguy]

I am from Duluth MN and we usually do a thickened edge slab making the outside 18" of the slab atleast 8" thick

 

[CanuckGT]

I am in the process of building my 28'x38'x10' up here in Ab,Canada and the code is anything over 100m2 you need to go a min 4' down then a 24" footing...talk about a dream crusher,I had to scale back my garage to just come under the 100m2 as I just couldn't justify spending the extra $$ to build such a foundation at this time.

If you go over 100m2 I would consider a pole building ,alot less work than 4ft footings...

 

[Laredo]

If you go over 100m2 I would consider a pole building ,alot less work than 4ft footings...

Pole building is not an option, I'm on a small city lot in a historical zoned neighborhood. The garage has to be aesthetically "time period" correct to match the house.

Thanks for all the tips - getting a contractor by this week to review the project...

 

[Kevin54]

I don't like a building to be build on a flat slab for the reason of the bottom plate in contact with the slab. Any water runs up against and can be absorbed in the wood and whatever wall covering. If the slab has a curb then all the better. Anything I have built has always had a foundation down to the frost line. Granted that you don't see it once it's backfilled and floor poured, but I think it is a better way to go. But you know how opinions are.