The floor in the produce section of the Alaska Commercial Co. store after polishing looks like new despite 40 years of wear and haphazard patchwork. The store is located in rural Sitka, Alaska, which has no road access. All supplies, personnel and equipment had to be transported to the jobsite by air or ferry.
A shot of the floor before polishing, showing the delaminating epoxy coating. The store needed to remain open for business during the rehab, so the repair and polishing work was done at night to minimize inconvenience to the customers.
The stenciled logo of the Alaska Commercial Co. is prominently displayed in the gift section of the store. "I wanted to create a logo with the feel of an old, weathered sign as background to a crisp new banner as a visual allusion to the facelift the store had just received," says Vermillion.
A view of the polished floor in the deli section. The existing concrete was very porous, so several different chemical densifiers were applied during polishing to improve the floor's durability and stain resistance.
A close-up of the stenciled logo, which pays tribute to the company's status as the oldest retailer in Alaska. The logo is 7 feet in diameter and was colored with an assortment of custom-mixed stains applied by sprayer, art brushes, rags and sponges.
The challenge
The Alaska Commercial Co., which operates a busy supermarket in Sitka, Alaska, is the state's largest and oldest existing retailer. Unfortunately, the 40-year-old floor in one of its facilities was not exhibiting the same longevity and was showing its age. The owners had covered the floor with a stained epoxy coating, but were disappointed with the performance. After only two years of service, the epoxy was already delaminating. What's more, underneath this coating were at least four different major slab-on-grade additions to the original slab, plus multiple repairs and modifications with trenches and in-fills.
Project goals
"It was apparent a major rehabilitation of the floor was necessary," says Jim Vermillion of Concrete Polishing & Artistic Staining of Alaska. "The owners first considered replacing the failing epoxy with vinyl composition tile. After consultation and evaluation, they realized that although the initial cost of grinding and polishing would be higher, the life- cycle cost of their floor would be the lowest if they elected diamond polishing and staining." This solution also allowed the owner to put the corporate logo of the Alaska Commercial Co. in the floor, which was achieved by applying a custom stencil and then staining.
The project entailed approximately 20,000 square feet of polishing work, performed in coordination with a major interior renovation that involved moving walls and entrances. In addition to removing the coating, restoring the floor to like-new condition involved patching unfilled foundation sections and misaligned slab edges. Several new trenches cut into the floor to accommodate new plumbing and drains also had to be filled and repaired.
Secrets to success
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Early on in the project, Vermillion discovered that the existing concrete was highly abrasive and the polishing crew completely wore out a set of diamonds after grinding only 1,000 square feet. "As it turned out, we learned that the local aggregate is a soft shale containing a high concentration of zirconium. A call to our diamond tooling supplier resulted in a new diamond recommendation, a prompt shipment via priority mail, and much better performance on the rest of the job," says Vermillion.
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To resurrect the old porous concrete and turn it into a hard, durable surface, Vermillion used three different types of chemical densifiers during the project to achieve different effects. In addition, in the store aisle where vinegar and salad oils are stocked, he applied a special penetrating sealer that protects concrete and other porous surfaces from oil and food stains.
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For the Alaska Commercial Co. logo, a custom stencil was computer cut in vinyl from digital art and then applied to the polished floor, followed by staining. "I used an assortment of stains custom mixed to achieve an aged effect. I mixed black, red, blue and various browns with assorted dilutions of water, alcohol and acetone solvents," says Vermillion.
Equipment and material suppliers
Floor grinder and diamond tooling: Substrate Technology Inc.
Chemical densifiers: L&M Construction Chemicals (SealHard, FGS Hardener Plus and LiON Hard)
Penetrating sealer: L&M Construction Chemicals (PermaGuard SPS)
Stains: Ameripolish (for main floor); L&M Construction Chemicals and Substrate Technology (for logo)
Find manufacturers of polishing and grinding equipment.
Find manufacturers of concrete densifiers.
Find manufacturers of concrete stains.
Contractors
Concrete polishing: Jim Vermillion, Concrete Polishing & Artistic Staining of Alaska
Chugiak, Alaska
General contractor: Hays Construction Co., Littleton, Colo. (www.haysco.biz)
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