No Crushed Base

[mobiledynamics]

Is there any applications, where concrete is just laid right ontop of removed old concrete (where there is dirt underneath) and new concrete is put it without any stone base.

 

[PugetDude]

Is there any applications, where concrete is just laid right ontop of removed old concrete (where there is dirt underneath) and new concrete is put it without any stone base.

Why not do it right- the old concrete failed for a reason.

 

[ddurrett896]

I demoed my old garage and re-built it twice as big. Paid $200 for a soil test that confirmed there was no need for any sub-base.

 

[mobiledynamics]

PG -

Heh, I'm just looking around ....on various summer *to dos* everyone has got going on....
And maybe he was the lowest bidder, but it was a straight rip and replace. Knocked it out in one day with no stone base, hence I was curious

 

[ConCretin]

The only reason to remove otherwise suitable native material and add stone is to provide a capillary break and make the surface more resistant to getting muddy and rutted by rain and construction traffic. The question is whether your "removed old concrete" is a suitable material.

Are you talking about processed concrete that has been run through a crusher or big ragged chunks of concrete?

 

[In2toys]

out here in Colorado a few homebuilders don't spec road base under driveways, and garages. No wire or bar either. keeps me busy tearing the new concrete out when the expansive soil underneath does what it does. 300-800k houses

 

[mobiledynamics]

LLWF -

No processing of old concrete. Just demoed the old stuff out (dirt base underneath) and not too long later, pump truck....I was saying what happened to the PREP..

 

[ConCretin]

Ohhh, so the old concrete was removed and you are placing the new slab on the original base material? My original response would still apply. Assuming the material that is there is suitable, there is no reason to dig it out just to add stone.

The next question would be; why was the old slab removed? Obviously if it's potentially related to an inadequate base i.e. large, displaced cracks, etc then that must be addressed.

 

[Arkive]

How pristine is the compacted soil underneath? I have a hard time believing the old slab came up like a pancake off a griddle. How close are you to the water table? Is there any drainage that runs towards the slab from any direction that could compromise the dirt? Are you putting a vapor barrier down? I assume yes on that one and if not then absolutely yes put a base down.

I personally would put a base because I've been burned enough to know it's almost always cheaper to do things once for more money than the alternative. However, if you're moving soon or have low garage loads and very high confidence in the soil I could see you skipping it.