Building a shop...concrete slab question!!!

personally, if you're wanting a 9000lb capacity lift I would go with a 4 post. it's much less weight per post, and you don't have to worry as much about centering the truck so it doesn't try to tip a 2 post and tear a couple of the threaded rods out of the slab   and where I'm at, we measure concrete thickness by using a PSI scale.  as in how any pounds per square inch can that that desired thickness of concrete support.  And for just a personal shop that will be used for mild auto mechanics and occassionally some light commercial duty you can usually run a 4" thick slab for the entire building. I would also suggest you have them trench out a 12'x20' area right where the lift will be and run 6" thick concrete there due to the weight of a vehicle and the lift it will be on, plus you might want to park a vehicle under the lift as it is in use also. as for the foudation edge these guys are talking about, it's not really ncessary as long as tied rebar is used throughout the slab.  This is going to be an all steel building right?

The foundation edge that i was talking about is reguired where im at. Also with the rebar being tied un the slab there is really no reason to use fiber mesh unless you want to. It might help with the cracks from seperation alittle bit more. I would also trench out where the post legs will sit at. You also might want to bend the bottom end of the treaded rod that goes into the concrete to help with the bolts wanting to pull out. 

only 3 guarantees on concrete1 its gonna crack2 it wont burn3 noones gonna steal it

Thanks for all the help guys...the reason for a 9k lift is most of the 2-post lifts i've seen are 9k...I will never have a 9k vehicle on it...the heaviest truck ill ever have on it is a 4 door 1500...if I ever work on a 2500 or 3500 i'll prolly just use the lift to help lift the cab etc. Like some have stated...it will be a hobby shop that is used mainly to work on my own trucks...and occasionally on friends trucks. The lift will be used twice a week tops...Thanks again.

---------------------------------------------Originally posted by thacru78Thanks for all the help guys...the reason for a 9k lift is most of the 2-post lifts i've seen are 9k...I will never have a 9k vehicle on it...the heaviest truck ill ever have on it is a 4 door 1500...if I ever work on a 2500 or 3500 i'll prolly just use the lift to help lift the cab etc. Like some have stated...it will be a hobby shop that is used mainly to work on my own trucks...and occasionally on friends trucks. The lift will be used twice a week tops...Thanks again. ---------------------------------------------I believe  you meant 4 door f250

Do you have the lift yet ? If not I found this on C-list.>>>>>>>>>>>>> http://sanantonio.craigslist.org/tls/1386617074.html  

ask for bridge mix have em pour some text mixes if it doesnt test high enough they have to pay to repour it that way it wont crack

6" slab
#4 rebar @ 18" o.c.
18" x 18" perimeter footing
Spread footings at each column.
I have a 10k 2 post anchored to a 5" slab using those Simpson titen drilled anchors. They're supposed to be better than epoxy anchors. And epoxy anchors test just as well as embedded anchors. I haven't had a problem with the lift yet. Been using it everyday for a year. I'd do the thicker than 4" if you intend to drive a vehicle on it. Ask the contractor to get you the mix designs on the mud. See what kinda break results the mixes are getting. I'd go with a 4000psi mix. Idk what kinda freeze thaw conditions you have or what kind of soils are there. But concrete is just like anything else, you usually get what u pay for. People that do a good job want more to do it.