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RE: Flat Floor

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Bill pointed out the web site that was developed by the Face Company for measuring floors and getting them to comply with the F numbers that were developed by the Face Company using measuring machines developed by the Face Company, for money that your client must send to the Face Company. I don't have too much heart burn with the Face Company for their efforts. But they are a bit self serving.

But I do have a concern as to the inappropriate application and expense. One of the largest slab on grade contractors is the Kalman Company. They can do super flat floors, but you have to ask if it is necessary. For automated rack storage systems you may be able to make that argument. But for conventional warehouses, I think that the old ACI 117 and a prequalified contractor are adequate for flatness tolerances.

I think that the owners money is better spent on eliminating control joints, proper armoring of expansion joints, and proper detailing to avoid vertical differential movement of joints in fork truck traffic lanes. Damage to fork trucks due to deterioration of control joints and maintenance of unnecessary control joints are where your real costs happen.

Call Kalman. They will install a slab that will get the performance that you need without arbitrarily specifying an F number and incurring expenses that you don't need. Don't limit yourself to Kalman. Call other GOOD concrete floor contractors, and get their opinions. Craft a specification that gets you the performance that your client needs. I just happen to have the most personal experience and confidence in the work that Kalman does. I also like the way they eliminate most joints in a slab on grade. They also have a top quality control system.

As Face points out, what do you do if the slab does not comply? That is where it gets ugly, the Owner will not be happy, and lawyers spring up from the underground abyss in which they reside to bring devastation to those who live in the light;>) Be well and stay away from the dark side.

Harold Sprague

From: richard lewis <rlewistx(--nospam--at)>
Reply-To: <seaint(--nospam--at)>
To: seaint(--nospam--at)
Subject: Flat Floor
Date: Thu, 23 Sep 2004 15:03:54 -0500

I have a client who has asked for an F100 floor for a warehouse I am
designing.  I'm not sure what he is asking for and want to ask some

Now I do know about the flatness number system, the overall values and
the minimum local values for Ff and Fl.  I assume he will want an overall
value of F100.  The question I have is the standard for classifying the
floor.  I have a few articles form magazines I have clipped out over the
years and I see different values for classification.  I have one article
that calls an Superflat floor of F values of 50 and another article that
calls a Superflat floor of F values of 100.  Are there standards defined
in the ASTM E1157 that define Flat, Superflat, etc?

The overall flatness number is typically 50% higher than the local
numbers.  With a F value of 100 for overall system the local numbers
would be 67.  Is this what is typically specified for Superflat floors?

The next question has to do with the practicality of the floor.  It is a
warehouse with pallet racks.  The racks are about 20 feet tall.  Forklift
traffic is the reason for the flatness.  I know the Owner is the one who
needs to determine their personal needs, but would an F50 floor work just
as well for this type of use.  Has anyone else had experience with lower
flatness numbers working well with fork trucks and racks?

Appreciate any insight you may be able to give.


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