Completed in two separate pours, this store project features a left side finished with black concrete seeded with M.O.P. Italian red granite, and a mine byproduct of 3/8-inch aggregate. The form dividing the two pours was cribbed like a large half-moon with the concave side facing east. The left side of store was poured natural gray with no seed.
The project objective was to create an aesthetic look where heavy concrete terrazzo meets a lightly ground salt-and-pepper surface, with a topical dye and sawcuts applied to the left side.
The owner wanted a look where "two different floors come smashing together."
After pouring and seeding the left side, the contractor made minimal sawcuts in for crack inhibition, then applied a hydration blanket for even curing.
Then the center arch form was stripped. Using a 4-inch angle grinder with a diamond blade, the contractor hacked up the crescent to simulate the look of a massive crack, as per the owner's request. Then he poured the natural gray up to the massive 80-foot-long manmade crack. He applied a hydration blanket to the left side of the store and allowed it to cure for two months.
He returned to intensively grind the seeded side to find all the seed and chip. He lighlty ground the right side to a fine salt-and-pepper look. Then he sawcut a tile pattern, airbrushed a terra cotta/coffee bean stain, and grouted the entire area. Finally, he polished the entire surface to 8000 grit.
"The challenge for me was keeping the floor flat from concept to install where a heavy terrazzo floor meets a salt and pepper floor—if you think about this, it was nerve racking," he says.
But the sweat paid off.
"We had a lot of fun on this job, and the client says, 'I'm tired of getting compliments on this floor. I have to explain what we did to every single customer!'"