two post lift foundation question

[K72nova]

I bought a house about a year ago and it just happened to have a 24x30 shop in the backyard, anyway because I didn't build the shop I don't know what the concrete under it is like. I am looking at installing a 2 post lift and the requirements for what I'm looking at are 4" deep concrete that is 3000 psi. Is there an easy way for me to figure out what I have as far as concrete goes? The house was built in 2000 and I can ask neighbors when the shop was built if it will make a difference. Also if the concrete is not up to par does anyone know what the best method would be to fix it or has anyone done this before? The plan right now if it is not what I need is to cut out a 4' x 4' square and dig down to 6-8".

 

[Outlawmws]

Go ask to see the permits and drawings filed with the city/county when the permits were applied for.

 

[camarotoolman]

I think you can just drill a hole, when the bit brakes though you will feel it mark the bit (tape) etc. pull out and measure. I think 4x4 cut outs are over kill, 2x2', 1 ' deep / some bars and anchor bolts.

 

[Danglerb]

The more "garage" side of the forums may know more, but 4" is a MINIMUM depth. Pretty sure some straight forward way of "testing" concrete psi must exist.