6 Rules for Avoiding Concrete Floor Disputes
Allen Face, Founder and Principal,
Allen Face & Associates,
Wilmington, North Carolina
As the author of the F-Number System and a principal inventor of superflat floor technology, Allen Face is a leading authority on the design and construction of concrete slabs-on-grade, and is considered the world's preeminent authority on floor profile specification and control. His company offers a full range of related consultation services including design and specification assistance, contractor training, forensic analysis, expert witness testimony, and the presentation of both public and in-house educational seminars.
This year, our consulting firm will probably be asked to provide expert witness services on a dozen or more serious concrete floor disputes. In most of these cases, a total defeat would be catastrophic to the flatwork contractor, who is usually the least substantial (and thus the most vulnerable and easily leveraged) of the contending parties.
If past experience is any guide, the unfortunate people involved in these cases will all have several things in common:
None of the parties will believe that they are truly at fault. None of the parties will have any real understanding of the technical issues involved.
All of the parties will presume that the "science" of concrete floor construction is well established, and that ACI documents are the irreproachable embodiments of that "science".
Without exception, every concrete floor related lawsuit and arbitration with which we have been associated in the past twenty years could have been avoided entirely if just one individual, regardless of his/her affiliation, had a) understood the true state of affairs that exists in the concrete flooring industry, and b) then acted upon that knowledge prior to the floor's installation. That dangerous state of affairs may be summarized as follows:
Concrete floor design and construction is still far more art than science. Structural engineers have no reliable resources on which to base either their thickness determinations or their crack avoidance schemes. Floors can be constructed in full accordance with present ACI recommendations and still crack, curl, and spall unacceptably. There is no natural dynamic in the present construction environment that will ever rectify these problems.
Owners and their architect/engineers don't trust contractors, and the reverse is equally true. When something goes wrong with a floor designed by a licensed structural engineer in full accordance with (presumably infallible) ACI recommendations, contractor misfeasance is the only logical conclusion. Of course, the fact that the contractor is usually owed a substantial sum when the problem appears, also makes it particularly convenient for the owner to be convinced of the contractor's culpability. And in the end, if the problem is eventually rectified at the contractor's expense (as it usually is), then there is no motivation whatsoever for even identifying, no less correcting, the fundamental misconceptions that actually gave rise to the failure. Sadly, none of the above is going to be changing anytime soon.
Even if the relevant ACI documents could be updated immediately, it would take years for the information to trickle its way down into plans and specifications. Until that time, as a matter of urgent self-interest, it is incumbent upon every flooring contractor (since his money is at the most risk) to adopt a pro-active strategy specifically aimed at problem avoidance. The following six "rules", if followed scrupulously, will effectively eliminate the possibility of becoming involved in a "company threatening" floor slab dispute:
Rule # 1: The flatwork contractor is the designated "fall guy"
Whatever the problem, the lowly flatwork contractor is the one who'll be squeezed into paying the most to fix it, regardless of who's actually at fault.
Rule # 2: No surprises
Never allow your customer to say he's surprised by anything you've done. From the outset, make sure the owner fully understands (and formally accepts!) how the floor is likely to perform - especially with regard to cracking, curling, and joint rocking.
Rule # 3: The big money is in the details
Read every word of every contract, every specification, and every drawing. If you're tied to the General Contract, demand a copy and read it too.
Rule # 4: The design is out to get you
Most engineers are not slab-on-grade experts, and the great majority of serious floor problems result from faulty design, not faulty installation. As a minimum, take exception to any interior concrete floor specification that:
- Treats shrinkage and curling as defective behavior
- Sets the control joint spacing in feet at greater than 6.1 times the square root of the slab thickness in inches.
- Fails to prohibit the use of air entraining admixture
- Fails to exclude the ACI-117 (+ 3/8", -1/4") slab thickness tolerance
- Fails to acknowledge the rocking potential of undoweled joints
- Requires the accurate location of light WWF (6-gauge mesh or smaller)
- Sets the maximum slump below 5"
- Prohibits the controlled addition of mix water on site
- Prohibits the application of water to the surface during early finishing
- Omits daily F-number testing
Rule #5: If it isn't in writing, it didn't happen
Any change that's important enough to make is important enough to document
Rule # 6: Know when to walk away
There are some customers too dangerous to work for. When a design is defective (see Rule # 4) and the owner refuses to be educated, quality-of-life considerations require you to walk away. Exercising the good judgment to pass on a losing proposition, no matter how large the job, will not only avoid the cost and anguish of the eventual lawsuit, but will also greatly enhance both your self-esteem and reputation.
Of course, flatwork contractors are optimists by nature, and there will always be plenty of firms that won't find it within their capabilities to heed any of this advice. But they're just among the "unlucky" ones who'll be looking for my phone number next year.
© 2001 L&M Construction Chemicals, Inc. | ConcreteNews Summer 2001.