Clark Branum, with Diamatic USA, led a recent webinar for the American Society of Concrete Contractor’s Concrete Polishing Council (CPC) where he described the contradictions that can crop up in polishing contracts. And remember that these contradictions may not be just within the polishing portion of the project specification. “Most contradictions occur in other specs for the same project such as the cast-in-place specification, which may call out different finishes and mixes for different areas of the project. This most often causes confusion between the trades and the concrete contractor.”
Branum reminded contractors that the specification portion of the contract is a legal document that can be used against you in court, so reading and understanding the provisions of the spec is critically important. The spec defines the scope of work and the expectations of the designer and owner.
There are typically three sections to a specification: general summary, materials, and execution. Each section has requirements that the contractor should review to make sure they are acceptable and don’t conflict with requirements in other parts of the spec.
In the general category, one important section to check is quality control. Does the specification require gloss or distinctness of image (DOI)? Does it indicate which devices to use to measure? Who is responsible to measure the polishing results? Are the CPC Polished Concrete Appearance Chart Level and Aggregate Exposure Chart Class specified? This section will also indicate which reference documents the designer has relied upon—make sure you agree with those requirements? Under which specific version and which section of the references are you performing?
For materials, be sure to understand what materials are permitted, what materials are required, and how to propose alternative materials. If you have more experience and confidence in something different, make sure the specifier knows that and understands the ramifications of a specified material.
The execution requirements can just call out the end result or can indicate the polishing process step-by-step. Are F-numbers specified and are they consistent with the expected polish? Is the curing method for the slab appropriate for the finished result they are looking for? How will the floor be protected between when the polishing is done and the final spiff polish?
Branum said that the best way to resolve any contradictions is to cover them in the pre-construction meeting, where you should come equipped with the CPC Checklist for the Polished Concrete Pre-Construction Conference and the CPC Supplemental Checklist for Concrete to Receive a Polished Finish. Present any contradictions in writing and reference industry standards wherever you can. Get a written copy of the changes agreed upon at the meeting. And review the mock-up with a walk-through. Remember to not take special care to make the mock-up perfect—it should be representative of the final floor.