A guide for defining polished concrete
Most of the time there is an interesting trend that occurs when I open up a set of plans. The finish schedule will call out quite interpretive or ambiguous text for the concrete flooring. It may say “polished concrete” or polish floor or use the polish sealer, and that’s it. No prescriptive process included. The specification sheet is absent of any details.
This leaves it to the polishing contractor to determine or define what that means. It could involve a phone call to the architect. This may lead to a phone call to the owner to define what they want. But really the architect, owner, and general contractor are depending on the polished contractor to define the specification after the design process has occurred.
There are the liability and design implications for this practice which we can save for another article. What is the right thing to do when an architect is vague about defining the process of polished concrete?
Communication in commercial construction with polished concrete today
At this point, anyone with any sense in construction would know to send an RFI (request for information) to the architect. This will clarify and define a prescriptive process. Some estimators are very professional at facilitating the communication between the concrete polishing contractor and the architect.
In a perfect, world we would have to assume a general contractors’ estimator would respond to forwarding an RFI. The Architect then responds with a specification on what the floors require, the flooring system, or polishing process.
However, communication is generally poor in construction. Having a vague specification is a symptom or illustration of this. In many cases, the floor surface does not meet the required floor flatness.
Concrete contractors should have a meeting with the polished concrete contractor during pre-construction. see ASCC recommendations. In renovations, it must be clear that the expectation is set ahead of time based on the existing concrete condition, ex. Staining from oils.
Do you want a contractor to define what polished concrete is?
When there is no communication, we have subcontractors, owners, or GCs specifying what polished concrete is. At bid the result for a general contractor is getting a wide range of bids which will include many different processes. Some that involve grinding, some that don’t. Maybe there is honing, maybe not. Some may include polishing and some may not.
As a side note polishing concrete is similar to sanding wood with different grits of sandpaper. There is rough sanding, honing, and high grit polishing. Polishing results in high gloss with good light reflection.
A concrete flooring surface specialist
Polished concrete needs to be done by a specialist, not someone that specializes in flat work. Many times the general contractor enrolls their painter to roll an acrylic sealer on the floor (and without any prep) and define that as polished concrete.
A concrete surface floor specialist is going to have the necessary machine, tools, and knowledge to install polished concrete. An architect should write the specs based on the traffic on that floor, with help from Industry authorities and associations. It could be foot traffic it could be vehicular.
You can not push this past a building owner/customer and think it won’t be a major expense on a final punch list. There is no comparison for a polished concrete floor.
Considerations when choosing the right concrete polishing contractor
It makes it really difficult for a General Contractor to determine what contractor to hire when half the bids are just as vague as the blueprint and one may call out a 3 step process, one a 6 step process, and all have different chemistry/materials used at various dilutions, and applied at different coverage rates. If the flooring material isn’t called out, how do we know what the chemical resistance and durability are when comparing bids.
Is the contractor that is vague on his proposal going to show up with OSHA compliant equipment and have the proper hazard planning documents? Does the vague contractor have a training program to use the acceptable methods for controlling silica dust?
OHSA has moved to treat Silica dust similar to Asbestos. Do you really want to pay the OSHA fine because someone on the job site doesn’t have the right equipment? The polishing installer needs to know the acceptable methods of safely operating the equipment. Which polish contractor has a tailgate safety meeting?
So what is polished concrete?
For the last few decades, the industry has struggled to reach a consensus on what it is and who defines it. We have had competing associations with different definitions and opinions regarding polished concrete. In my opinion, in the last few years, many of these concrete polishing industry associations have merged, have the authority and reached consensus on defining polished concrete.
Use the definition of the American Society of concrete contractors ASCC’s concrete polishing councils’ definition PDF if the specification is vague, and the polishing contractor is not getting feedback from the architect.
Polished concrete defined is by the CPC as anything grit level 400 and above. In many cases order to get the proper clarity at that level, you have to cut it open and hone it properly.
As far as chemistry, I use industry standard materials or products that have characteristics exceed the industry standard. I think as a polishing contractor I should exceed the minimum defined grit. We have the responsibility to be an advocate for the customer and general contractor interests.
We have to promote what polished concrete flooring offers. Yes, it is more cost-effective as a result of lower maintenance costs and because it is so easy to clean. It’s important to stress the strengths and limitations of polished concrete because we want everyone to have a clear picture of what polished concrete is.