Chris Sullivan, QC Construction Products: A warm or windy day can make strippers dry out too quickly. Dampen a piece of absorbent material such as an old cotton sheet or towel, place it over the stripper, put plastic over that and leave it overnight. This creates a humidity chamber that keeps the reaction running for a long time. It also makes cleanup easier, because as the sealer breaks down it wicks into the towel, and you can just throw the towel away, sealer and all.
Shawn Halverson, Surfacing Solutions Inc.: Lines where carpet glue was removed can ghost through a new finish. Spreading a chemical stripper over the whole floor instead of applying only to the glue lines can help achieve a more even finish.
Jim Cuviello, Cuviello Concrete: Be aware that if you liquefy glue on soft concrete, it can penetrate the pores, resolidify and prevent absorption and proper reaction of a densifier. This will also prevent proper penetration of dyes. There is no way to remove the liquefied and resolidified glue unless you grind the concrete past its penetration depth.
Thomas Sylcox, Floorgen: When grinding, clean the floor with an autoscrubber between steps. This will show any missed spots. It will also show uneven scratch marks that would cause nightmares in the polishing stages.
Halverson: Carpet glue, mastics, epoxies and urethane sealers are all pretty darned hard to remove. And the harder the concrete is, the more difficult it is to grind these off. Work back and forth between the material you’re trying to remove and areas of clean concrete to clean the sealer off the diamonds.
Sullivan: There is a big difference between a chemical stripper and a solvent. Solvents like mineral spirits should not be used to strip sealers or coatings. Instead of destroying and removing the material, solvents simply re-emulsify it, so when the solvent evaporates the sealer reforms on the surface.
Halverson: When you remove tile, whether you prep the floor by grinding or chemical stripping, the grout lines will ghost through a stain. Grout has different vapor transmission properties from tile, so it changes the nature of the concrete underneath. We put down an overlay before staining a floor that had tile before.
Sullivan: One common misconception I hear all the time is that if you want to strip a coating you need an acid. Muriatic acid (a dilution of hydrochloric acid), phosphoric acid and sulfuric acid cannot be used as strippers. They will have no effect on a sealer. Think about it — the container the acid comes in is made of a plastic similar to the material you’re trying to strip away.
