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janetcal
08-29-2010, 05:09 PM
Has anyone ever seen or heard of pouring a cement patio on top of dirt instead of on rock? We live in Western Pennsylvania.

Fireguy97
09-02-2010, 10:48 AM
I've heard of it, I've seen it done, but I'm an Irrigation Contractor not a Landscaper, or a concrete guy. Do you mean gravel, or rock? I know that if you did pour over soil, it would still have to be compacted, and very stable to start with.

Mick

Terry
09-02-2010, 02:40 PM
Most of the concrete driveways and patio's in Seattle are poured over dirt.

http://www.easydigging.com/Drainage/installation_french_drain.html

cacher_chick
09-02-2010, 04:51 PM
If you live in an area in which the ground freezes and thaws in the winter it would be a big mistake.
The high moisture content often found in soil causes it to expand greatly when it freezes & then the slab will heave and crack.

Rock or gravel is used as a proper base because it allows water to quickly drain and moisture to dry outward.

dlarrivee
09-02-2010, 05:00 PM
Use concrete not cement, and use rebar, and ensure the subgrade is well compacted.

hj
09-04-2010, 02:23 PM
Unless the dirt has been disturbed, it is probably as compacted as it is going to get. Many people use the terms cement and concrete interchangeably, even though one is a subset of the other.

dlarrivee
09-04-2010, 03:18 PM
Unless the dirt has been disturbed, it is probably as compacted as it is going to get. Many people use the terms cement and concrete interchangeably, even though one is a subset of the other.

I'm just clarifying because I've seen people mix straight portland cement with water and expect it to work like concrete.

Cement is an INGREDIENT in a concrete mix.

janetcal
09-12-2010, 12:37 PM
yes we used 2 inches of rock over the dirt and will pour 4 inches of cement.... I wanted 4 inches of rock and 5 1/2 inches of cement but contractor says we dont need that much because it is a patio and not a driveway.. Im just concerned about the winters here in western Pa.. I know the first year is crucial so that the cement dont crack.. someone told me to also get some hay or straw and leave it on the corners of the patio after the cement has dried to cure the patio.. anyone hear of that? thanks for the feedback