Q. I am the building manager for a large church on the East Coast. We recently have contracted with a company to grind and overlay about 5000 square feet of our church (hallways, atrium, and several rooms).
I have found that in our area, all of the decorative concrete workers exclusively do outdoor stamped concrete (pool decks, etc.). I am quite nervous that our contractor might not be fully aware of the differences in grinding and sealing indoor concrete.
Our existing floors are concrete with carpeting held down with an epoxy adhesive. My first concern is that our floors will be ground with an open machine that will spew concrete dust everywhere. I am concerned about the health risks because we operate a day care center in the building. I also am concerned about the cleanup. We have 40-foot vaulted ceilings—will we have to get scaffolding to clean our walls?
I am told that there is no machine that will handle the removal of the carpet epoxy, but my online research says otherwise. We are slated to start demolition shortly and so would appreciate any quick advice you can offer.
A. The diamond polishing industry is almost all dry grinding now with specialized vacuum pick up technology that eliminates 95.9% of the dust. The vacuums are connected to the housing around the grinding heads so no dust escapes into the air. The process is quiet as well. The same can be said for floor surface preparation, which includes removing the carpet adhesive. It's all done with the same machinery.
If your contractor hasn't done this work before or doesn't own the right equipment, you should be concerned. Many manufacturers of concrete grinding and polishing equipment offer training and might be able to tell you who in your area has gone through the class. For a list of manufacturers, click on Industry Sourcebook on the Concrete Construction Web site and search for “Grinding & grooving machines, walk-behind” or “Surface scraping machines.”