Flooring Finishes Part 3: Health Information

March 01, 2018

Flooring Finishes Part 3: Health Information


UV-cured urethane finishes are sometimes mistakenly referred to as ‘water-based’ because they don’t contain solvents, but they are actually not water-based. They are 100% solids, meaning they have no solvent OR water content. They dry purely by exposure to UV lights, and once that reaction is complete there is no further off-gassing. They are also easy to clean with benign, odorless cleaning agents that leave no residue on the floor. These characteristics make UV-cured urethanes a good alternative for people looking for a floor and cleaning system that won't introduce any odor or off-gassing into the home.


The natural oils that are the base ingredients in penetrating oils will not dry quickly enough for practical use unless solvents are added. The types of solvents used by the penetrating oil manufacturers vary, and usually depend on which natural oil is chosen as the base ingredient. Penetrating oil manufacturers usually try to use relatively benign solvents like white alcohol, but consumers concerned about exposure to these solvents should check the individual product information.

Generally, manufacturers who use penetrating oil finishes on their prefinished floors will allow the finish to cure for a period before packaging, but that curing process often isn’t 100% complete at the time of packaging. Once packaged, the curing process gets put on hold while the product is protected from air circulation. For that reason, consumers may detect a slight odor when a floor finished with penetrating oil is first installed.


In order to suspend the wax ingredients in liquid form, traditional hardwax oils contain very high solvent content. Their sale and application are not permitted in some regulatory areas.

Some of the ‘single-coat’ hardwax oils on the market are advertised as being zero-VOC. However, it’s important to note that this technology simply replaces the drying solvents with an isocyanate hardener that is added in just before the finish is applied, for a so-called ‘two-component’ system. Isocyanate is not classified in the U.S. as a VOC because it is not a smog-producing chemical, and manufacturers therefore aren’t required to include it in their total VOC calculation. But in many other countries isocyanate IS classified as a VOC, and is considered harmful. Being ‘Zero-VOC’ in the U.S. does not necessarily mean being free of odors or harmful ingredients.

Similar to prefinished floors finished with penetrating oils, floors finished with hardwax oils may have a slight odor when they are first removed from the packaging, as the finish may still be going through the final stages of curing.


Like UV-cured urethanes, UV oils are dried completely in a UV oven at the factory and will not off-gas in the home during or after installation. However, the cleaning and maintenance products for UV oil are the same as those for other types of oil and may contain VOC’s or have a slight odor. The maintenance system that Monarch Plank recommends for its UV-cured oiled floors, by Woca of Denmark, features a soap that is truly zero-VOC and virtually odorless.

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