Can Urethane Cement be Used as a Top Coat?
Urethane cement is a superior flooring top coat. It is stronger than epoxy, abrasion resistant, chemical resistant, and thermo-shock resistant. It is a preferred floor for pharmaceutical and food manufacturing facilities. Normally, urethane cement is applied over a concrete substrate, but it can also be applied to marine-grade plywood subflooring.
Components
The product is packaged in three pre-measured parts: a pail of resin, a pail of hardener and a bag of aggregate:
- Resin: The water-based resin is a blend of polyester-ether polyol and glycol ester, with coloring oxides and carbon black. The resin is free of volatile organic compounds.
- Hardener: The hardener is an aliphatic polyisocyanate consisting of hexamethylene diisocyanate (HDI), the homopolymer of HDI, and a pinch of methylenedicyclohexyl diisocyanate. The hardener gives the coating its abrasion and UV resistance.
- Aggregate: The sand/cement aggregate is a dry mixture of Portland cement, quartz and calcium/magnesium hydroxide. The material’s dust can cause lung injury or cancer, so it’s important to take suitable precautions.
Urethane Cement Benefits
Urethane cement is popular in applications in which cleanliness and water-resistance is important, such as the floor of a meatpacking plant, laboratory or brewery. It provides a number of benefits, including:
- Water and moisture resistance
- Strong and abrasion-resistant
- Resists a wide range of chemicals, acids and alkalis
- Stands up to high temperatures, thermal shocks and thermal cycling
- Seals, adheres to and expands/contracts with concrete to form a seamless topcoat that is naturally sanitary — it doesn’t support microbial growth
- Slip-resistant
- Color stability
- Can be steam/pressure cleaned
- Self-priming, self-leveling, cures fast and is low-odor
- Can integrate with a cove system for seamless flooring
- Earns LEEDS credits
- Multiple finish options
Urethane Application
No priming is necessary, but oily concrete slabs should be degreased. If the substrate is very porous, you can pre-prime to slow down resin absorption. The resin and hardener are combined in a large pail and mixed for 30 seconds with a low-speed power drill equipped with a 5-inch spiral blade. Mix in some of the aggregate and thoroughly blend for a minute.
Once blended, immediately apply the product to the wet edge by emptying the pail and spreading with a 2-foot pin rake, which should be set 1/8 inch higher than applied thickness of the screed. Trowel edges and drains. Roll and cross-roll with 15/16-inch spiked roller.
Don a filter mask and broadcast the remaining aggregate through the air at a rate of one pound per square foot. Complete the broadcasting within 15 minutes of mixing each batch. Cure time is eight hours at 70 degrees. If you wish, you can apply a color-fast top coat.