For a concrete patio, is 3 1/2" thick enough thickness?

Question

The guy thats doing our patio used 2x4's to frame the patio. We were told the patio would be 4" thick but the 2x4 is or course not really 2x4. So the concrete will be 3 1/2" thick. Is that acceptable for a patio?

Answer 1

you need a compacted base (dirt), 4" ABC (crushed rock), and 4" concrete.  All edges to have concrete turndowns (thickened concrete curb).  That is a standard concrete slab assembly.

Answer 2

More than acceptable. You shouldn't have that much weight on it. Normal driveways are 3 1/2" thick..

Answer 3

I'm not a patio guy, but, this sounds like what we did (with a contractor friend helping) and it's holding up fine. If you think about it, once you've dug the area and put in your 2 x 4's, the cement will actually go down farther and settle lower than the boards, so I would think you're good to go. Good luck. LT

Answer 4

It would be better, but not necessary to have it a little thicker on the edges.You don't need bigger lumber, just dig a little deeper near the edge, especially if there is extre concrete.