Concrete grinding & surface preparation in San Francisco, CA - a slab your coating grips

Most people call us because they're planning a new floor, maybe garage floor coatings or epoxy in a basement or shop, and the slab underneath has old paint, tile glue or a slick troweled finish. I'd rather spend the time here, because most coatings that peel had a problem in the slab before anyone opened a can. The price moves with the square footage, how much old material has to come off and how rough your coating needs the concrete to be. The schedule turns on whether the slab is new or damp and whether an older building needs a closer look first. At the estimate I check your slab and walk you through what each option means for your timeline.

First I find out what coating is going on, because that decides how rough the concrete needs to be. Diamond grinders suit thin coatings and reach right up to the walls, while shot blasting, which throws steel shot at the slab, is fast, nearly dust-free and leaves a rougher surface for thicker systems, so we pick the one that fits your floor. Our crew then grinds down the high spots and takes off old paint, epoxy and mastic, with dust collection hooked up to our grinders the whole time. In an older building with old paint or mastic on the slab, we take a closer look before anything gets ground.

Prep is usually the first half of a bigger job. If you want the concrete left bare, a freshly ground slab takes concrete sealing well, and if it's too cracked, pitted or worn for grinding alone, concrete resurfacing and overlays give you a new top layer to work from.

A lot of the slabs we prep here sit in buildings that went up before 1979, and the city's lead paint guide says those have a high chance of lead-based paint. The city requires owners of older buildings to follow lead-safe practices, which matters when grinding takes old paint off a garage or basement floor, and its guidance tells you to let your neighbors know at least three business days before the work starts and to post a "Lead Work in Progress" sign at the front of the home. Old tile glue has its own concern, because the Air District lists mastics and vinyl floor tiles among materials that might contain asbestos. Its notification rule applies to contractors and homeowners renovating a structure when the work will disturb more than 100 sq. ft. of friable, regulated asbestos-containing material. So on an older floor, we sort out what's on the slab and what the work calls for before a grinder touches it.

Past the paint and glue, we see plenty of painted garage floors and patched basement slabs, often with several old coatings stacked on top of each other. We meet the same floors on jobs in Daly City and Oakland, and we prep them the same way, matching the grind to the coating going on.