# Pouring a concrete slab - Do I need a 4" gravel base?



## tokuzumi (Nov 27, 2007)

I have a parking pad, built out of solid 4" X 8" X 16" concrete blocks that butts against my driveway. The size of the pad is about 9ft X 19ft. I'd like to just pull up the blocks, put some forms in, and pour some concrete, and so all that nice finishing stuff you are supposed to do to make the pad look presentable. Do I really need the 4" of gravel for a base? I live in GA, where Sonny Purdue has outlawed the rain, and it rarely gets really cold, so heaving would be a non-issue. The way I see it, if the ground is already compacted underneath, there shouldn't be much of an issue, right? The pad has been down for over 2 years, and erosion has not played a factor. Thanks for your input.


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## bebbconstruction (Nov 27, 2007)

*Parking pad or driveway*



tokuzumi said:


> I have a parking pad, built out of solid 4" X 8" X 16" concrete blocks that butts against my driveway. The size of the pad is about 9ft X 19ft. I'd like to just pull up the blocks, put some forms in, and pour some concrete, and so all that nice finishing stuff you are supposed to do to make the pad look presentable. Do I really need the 4" of gravel for a base? I live in GA, where Sonny Purdue has outlawed the rain, and it rarely gets really cold, so heaving would be a non-issue. The way I see it, if the ground is already compacted underneath, there shouldn't be much of an issue, right? The pad has been down for over 2 years, and erosion has not played a factor. Thanks for your input.


take up blocks and use a compacter, then just use some steel mesh to help stop cracking, even use some expantion joints which will help.


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## GearHd6 (Sep 2, 2007)

bebbconstruction said:


> take up blocks and use a compacter, then just use some steel mesh to help stop cracking, even use some expantion joints which will help.


If you've got a solid base that isnt topsoil you should be all set. If it were me i'd do like mentioned above. Throw down some wire mesh and make sure the contractor actually PULLS the mesh up into the center of the concrete. The mesh does no good laying on the bottom of the concrete. You wouldnt believe the amount of people I see that never pull the wire up. Mention to the contractor about putting "fiber mesh" into the concrete also. That usually adds about $7 a yard but to me its well worth money. It doesnt take the place of wire mesh but it reduces shrinkage cracks. I'd put in a couple expansion joints and then score it with a concrete blade once its cured a few days. I'd probably go with at least a 3500lbs mix if not 4000 if it were my pad.


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