Repairing a Concrete Floor for a Comdominium Renovation

An 80-year-old concrete warehouse floor gets a new life thanks to a thorough repair and a decorative finish.

Instead of ripping out and replacing the 80-year-old concrete floor during the lobby renovation at the Opera Lofts condominiums, the general contractor chose a repair and wear topping system with a decorative finish.
Instead of ripping out and replacing the 80-year-old concrete floor during the lobby renovation at the Opera Lofts condominiums, the general contractor chose a repair and wear topping system with a decorative finish.

The Opera Lofts condominiums in Downtown Chicago's South Loop have undergone a huge transformation in recent years. Once a warehouse for the Lyric Opera of Chicago, the building has seen renovations to offer unique living areas near the site of what Chicago hopes will be the 2016 Olympic Village if the city wins its bid for the games.

The original building was constructed in sections in the early 1900s over the course of a dozen years. In some areas the ceiling heights are 31 feet high, allowing for some unique mezzanines and bright, open spaces in the condo floor plans. Artifacts from the opera days, such as props and posters, decorate the common areas. With all this potential for a first-class building, the Opera Lofts developer knew he needed a solution to bring life back to the 80-year-old chipped and worn concrete floor in the 1,200-square-foot lobby, the main entrance where condo owners, guests and potential buyers are greeted by their first impressions of the building.

The general contractor on the job, with help from his materials manufacturer, developed a repair system that produced a concrete canvas on which the specialty contractor could apply a one-of-a-kind acid stained finish to match the uniqueness and historic ambiance of the building while avoiding the mess and price tag associated with a tear out and installation of a new floor.

Choosing a floor system

The design team had a few elements to consider in deciding a course of action for rejuvenating the lobby floor. First, there was the issue of time. With various trades working throughout the building and condo owners going about their daily lives, the floor couldn't be off limits very long. That point alone pretty much restricted a removal and reinstallation, not to mention the value of avoiding the mess and noise associated with that type of construction. In addition, although the floor had some gouges in it and suffered the usual life of an 80-year-old warehouse floor, the concrete was still in good shape with only mild static shrinkage cracking.

Another constraint was the threshold at the main entrance - there was only a ¼ inch of working room between the existing floor and the threshold. When taken as a whole, these elements pointed to a repair and wear topping as the most reasonable choice to achieve the finish the owner and design team were looking for that could also accommodate those tight requirements.

The specialty contractor hired to carry out the repair and decorative concrete work was Dan Wilson of Absolute Leveling Solutions out of Fort Worth, Texas. Absolute Leveling Solutions specializes in repair work and decorative concrete and travels the country for jobs of all sizes. Wilson completed the Opera Lofts lobby in four days, due in part to the fact that the condo owners and contractors finishing other parts of the building could be routed through a garage area to give him full access to the floor.

Day by day

On Day 1, Wilson prepared the floor. Wilson says self-leveling wear toppings, commonly referred to as overlayments, can be very sensitive, and he often backs up his work with a 5- or 10-year warranty so there's no cutting corners with a job like this. "It's important to have all the little gizmos and gadgets on the job," he says. "There's a talent to this kind of work, but there's also a science to it."

Before starting the job, Wilson used a hand-held moisture meter to test the vapor emissions in the floor. For this particular job the floor was in a good zone, but Wilson warns that too much moisture in the floor can cause delamination.

With the floor ready to go, he started surface prep with a diamond cup grinder with a vacuum attachment around walls and columns and used a shot blaster for the main part of the floor. "The shot blaster was used for convenience and production," says Peter Golter, senior territory sales manager with ProSpec, the manufacturer that supplied the repair and wear topping materials for the project. "The per square foot cost to prepare a floor is cheapest with a shot blaster, and you get the best profile."

Repair, priming and wear topping application took place on Day 2. Wilson filled in the hairline static cracks and other floor imperfections with ProSpec's Feather Edge, a cement-based repair product with fine sands that has the consistency of peanut butter and dries within 30 minutes. Wilson then applied ProSpec's Level Set Primer. "The primer soaks into the concrete and gives the self-leveler something to bite on to so there's no delamination," Wilson explains.

"It's a latex concentrate, and because we had an open and porous substrate, the latex was the perfect product for that," Golter adds. "The primer is diluted 3 to 1 and used over the substrate for a tenacious bond."

After the primer dried, Wilson applied ProSpec's self-leveling Level Set Wear Topping, a product that can be used as either an overlayment or underlayment depending on the circumstances. He used a trailer-mounted mixer/pump which allowed him to open product bags and mix materials outside then pump the mixed material inside, avoiding dust and noise in the building.

Another gadget Wilson considers essential for a successful wear topping job is a simple laser that reads temperature. "I have a laser that takes the temperature of the material and floor. If you have a cold floor and warm material, you'll shock the floor. You want both the floor and material to be about the same temperature to avoid any delamination problems," he explains. Wilson suggests one way to keep your product from getting too hot is to keep bulk bags in the shade if you need to store them outside.

Wilson stained the floor on Day 3. He used a pump sprayer to apply the first coat of stain and a complimentary stain for the second coat to give the floor the look of aged leather. He allowed the acid stain to dry before he neutralized and washed the surface with baking soda, cold water and mops. He washed the area again, shop vacuumed it dry and allowed the floor to air dry overnight before sealing it.

On Day 4 Wilson applied the sealer and back rolled it assuring proper adhesion to the finish floor. He added a skid resistance product to the epoxy urethane coating. "Because of concern at the main entrance over rain and snow, we wanted to make sure we had a safe surface for residents and visitors," he says.

The four-day project was a success, offering a one-of-a-kind finish for a one-of-a-kind building and giving a historic slab of concrete a future to look forward to.

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