Coating Do’s & Don’ts For Your Floors

There is a wide range of floor coatings on the market, and their use depends on the type of flooring and whether it’s for a residential or commercial setting, among other factors. Epoxies are typically used for industrial settings as they offer mechanical and chemical resistance.

Polyurethane coatings are more flexible, which makes them softer and more pleasant to walk on, so they are popular in residential settings. They are known for their decorative properties, as they are available in many colours and provide a high gloss finish. They are also easy to clean because they are somewhat resistant to contaminants.

In this blog, we’ll focus on polyurethane coatings, what implications to consider, and other coating do’s and don’ts for your floors.

General considerations

The main things to consider with coatings selection are:

• • The health impact on the premise’s occupants, pets and visitors and the person applying the coating.
• • Aesthetic factors such as the colour impact on different timbers and their sheen levels.
• • Functional properties like slip resistance and wear resistance, including on stairs.
• • The ease of application for the sander and finisher.
• • Productivity in terms of the person returning to the site to coat the floor.
• • How long it will take for the site to be re-occupied from both a health and coating-curing perspective.
• • Cost.

Factors that can impact a coating’s performance

When considering a coating, a number of factors can impact its performance, including:

• • The temperature and humidity of the room and of the floor surface itself.
• • If used on timber floors, the species of the timber, including aspects such as tannins. Tannins are the natural properties of the timber itself that are stored within the internal grains of the timber. When water or moisture permeates through the timber, the tannins can be brought to the surface, causing brownish or black stains (one reason why coatings on timber are so valuable).
• • Again, on timber floors, the extractable type and content. Extractables are materials that are often used to treat timber.
• • The age and storage history of the coating prior to use.
• • Whether premixing has occurred prior to use.
• • The phasing, settling or flotation of additives in the coating.
• • The sanding and application tools.
• • The application technique of the coatings.

The classes of coatings

The performance of a coating varies markedly between the type of coating and the class of coating. For example, between solventborne polyurethanes (PUs), oil modified urethanes (OMUs) and waterborne polyurethanes (WBPUs). Here’s a guide to coating do’s and don’ts specific to the different types.

Solventborne polyurethanes (PUs)

• • Health issues. You should consider that these materials contain volatile organic compounds (VOCs), which can cause (on a less serious level) headaches, nausea and nose, throat and eye irritation. Those working with PUs should use a respirator. All sources of ignition should be isolated prior to coating.
• • Wear resistance. Offer the most wear resistance and less maintenance.
• • Material factors. The premises should not be re-occupied until the coatings have adequately cured. Curing for three days at 25ºC is generally adequate to allow for the re-installation of furniture. Double this time for a temperature of 15ºC.

Oil modified urethanes (OMUs)

• • Health issues. See those for PUs.
• • Wear resistance. Offer less wear resistance than PUs and WBPUs.
• • Material factors. Don’t overlook the significant slowing of curing in cold weather. A three-day cure at 25ºC can extend to ten days at 15ºC.

Waterborne polyurethanes (WBPU)

• • Health issues. Don’t assume that waterborne coatings don’t contain VOCs and result in associated health issues. Most WBPUs contain solvents, which can trigger adverse reactions in those with respiratory issues. Those working with WBPUs should also use a respirator.
• • Wear resistance. Offer lower wear resistance than PUs but higher than OMUs.
• • Material factors. Waterborne have the earliest re-occupancy of the three categories — curing for two days at 25ºC is generally OK.

References

• 1. 2013, Coatings do’s and don’ts, Australasian Timber Flooring Association
• 2. 2018, Information about Timber Tannins, Commercial Systems Australia