[Top] [All Lists]

Re: Lifts - concrete psi

To: "Wayne Farrington" <>, <>
Subject: Re: Lifts - concrete psi
From: "Susan and Mark Miller" <>
Date: Fri, 29 Aug 2003 21:39:02 -0700
----- Original Message ----- 
From: "Wayne Farrington" <>
> The only thing that is still bothering me a little is the concrete spec.
> manufacturer states that for a 10K lift the concrete has to be 4in. thick
at a
> minimum, and 3000psi. My building manufacturer tells me the concrete is
> "guaranteed" to be 2500psi minimum (with an emphasis on "minimum", meaning
> may be more I guess) and near as I can tell the slab thickness is 5 -
> Of course the required slab thicknesses go up as the lift capacity goes up
> I noticed the 3000psi rating remains the same regardless. So I assume that
> slightly thicker then required slab does nothing to help my 2500psi
> Two different specs that are independent of each other?
> What do you think? How critical is that 500psi? Is there a inexpensive way
> test the psi rating of a slab? Would I be better off to cut two big square
> holes in the slab and pour two 6in. thick, 3000psi pads? I have no idea
how to
> tie them into the existing floor though. I suspect this may do more harm
> good by breaking up the "continuity" of the floor. But I'm no concrete
> Just trying to get a feel for how big a deal this is?

Call the lift mfg.  The added thickness may be enough to compensate for the
lower PSI rating, or that could be a number that isn't that important to
them - they may throw 3000 psi in the spec but just want it to be 'enough'.
Better for them to overspec than underspec, from their viewpoint.


///  unsubscribe/change address requests to  or try
///  Archives at

<Prev in Thread] Current Thread [Next in Thread>