Detached garage concrete floor recommendations

[bmwpower]

My garage is 30' x 30'. I will have a 2 post automotive lift, plus 4000lbs+ of Lista cabinets, unloaded. I want a floor that will never crack or give me prolems. I plan on finishing it with a quartz epoxy coating.

I was planning on pouring an 8" floor with 4000psi concrete with fiber mesh. No expansion joints in the floor due to lift requirements. Mason recommends expansion material around the perimeter of the garage floor.

How does all of this sound? Do I need more reinforcement, like rebar or is fiber good enough? Is 8" good enough? Is 4000psi good enough?

[Wgoodrich]

Sounds like you are building it to work on big bull dozers or an army tank.

4" is minimum 8" is great.

Fiber re-enforment is not recognized by the IRC yet a lot use it. Rebar is generally specked or at least re-enforsing fence is used.

Depends on what the building is made of. If a pole building expansion around the post would be good. If a solid building with no room for expansion such as concrete footers then expansion all the way around best idea.

There is never a guarntee not to crack, only best thing is best attempt with what we know to reduce the risk of cracking.

One thing to concern is if this building is heated you need to put your footers supporting that floor and building below the frost line. Good insurance even if not heated.

Good Luck

Wg

[bmwpower]

Sounds like you are building it to work on big bull dozers or an army tank.

4" is minimum 8" is great.

Fiber re-enforment is not recognized by the IRC yet a lot use it. Rebar is generally specked or at least re-enforsing fence is used.

Depends on what the building is made of. If a pole building expansion around the post would be good. If a solid building with no room for expansion such as concrete footers then expansion all the way around best idea.

There is never a guarntee not to crack, only best thing is best attempt with what we know to reduce the risk of cracking.

One thing to concern is if this building is heated you need to put your footers supporting that floor and building below the frost line. Good insurance even if not heated.

Good Luck

Wg

Yea, I'm going overboard on the thickness, but it makes sleep better at night (so far).

Building has concrete footers and block wall, 2 courses above the floor level. Footers are below the frost line. The building will be heated.

Thanks for your feedback, Wg. I'm trying to get as many bits of feedback as I can just to make sure everything is going to be done as it should. Sounds like I'm on the right track so far.

[Aviator]

The thickness of your concrete will affect the overall strength of your slab. Very simple, the thicker the concrete the more load it should be able to support. Providing... the subsurface is prepare properly, the concrete is consolidated well during placement (not pouring), and most importantly, it is cured properly.

With 4,000 PSI concrete (about a 6 sack mix) you need to be a little concerned with excessive shrinkage cracks. To ensure minimization of this make sure the finishers do not use excessive water during floating and when the concrete reaches its initial set (about three hours) use a commercial grade curing compound or cover it with plastic sheeting (visquene) and keep it moist. Hosing it down every couple hours for the first 24 - 48 hours should do it. Also, make sure the ambient temperature is at least 45 degrees.

PS: I am assuming you are tooling in control joints about every 15 feet.

[richnn]

Its also a function of the soil in your area ... its the second foundation. High moisture clay = trouble