On Apr 27, 1:05*am, Tony Hwang wrote:
Pat wrote:
A fairly simple job. *However, someone told me I must put dravel under
it first. *Is this gravel really needed? *If it is, why? *After all, I
already have the rock base, which is very solid, and rock is like
gravel. *It's just that dirt has filled in around the rock so it just
looks like dirt now.

You say nothing about your climate or location. *Do you have freeze thaw
cycles? *Gravel base helps keep the water away from the concrete. *Do you
have seasons? *Dry, wet cycles? *Soil expands when it gets wet and shrinks
when it dries. *Rock helps isolate the concrete from soil movement. *When
the soil is wet its load carrying capacity is diminished. *Concrete corners
may not have good support and break. *Generally rock under concrete is
essential. *Especially under driveways where there is loading from vehicles.

A thin layer of sand under the concrete allows up to 10 feet between joints.
The joints control where the concrete cracks. *If the joints are too far
apart then a crack forms before the joint is reached. *The sand allows a
little slippage so the joints can be stretched a little.

I figure 2.7 yards.

And no rebar?- Hide quoted text -

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