When installing flooring, you want to achieve the perfect look that is also durable and long-lasting. One way to do this is by using a polyurethane finish. While it is easy to apply, it’s important to understand the differences between oil-based and water-based finishes, the number of coats needed, safety considerations, and the equipment you’ll need.

Choosing Between Oil-Based and Water-Based Polyurethane

One of the first decisions you’ll need to make when applying polyurethane to a floor is whether to usean oil-based or water-based finish. There are pros and cons to each option, and the choice ultimately depends on the specific needs of your project.

Oil-based polyurethane is known for its durability and resistance to wear and tear. It’s also more resistant to chemicals and water than water-based finishes, making it a popular choice for high-traffic areas such as hallways and entryways. However, oil-based polyurethane takes longer to dry, emits a stronger odor during application, and requires the use of solvents for cleanup. Keep in mind that oil-based polyurethanes will also yellow with age.

Water-based polyurethane, on the other hand, dries faster and emits fewer harmful fumes during application. It’s also easier to clean up with soap and water. While it may not be as durable as oil-based polyurethane, it’s a good choice for areas that don’t see as much foot traffic or for people who are sensitive to strong odors.

Learn more about when to use oil-based versus water-based polyurethane.

How Many Coats of Polyurethane Will You Need?

Once you’ve decided on the type of polyurethane you’ll be using, the next step is to determine how many coats you’ll need. The number of coats required depends on several factors, including the type of wood, the condition of the floor, and the level of wear and tear expected. It’s important to allow each coat to dry completely before applying the next one.

While water-based polyurethane will dry faster, it typically will require more coats. Typically for a water-based finish, you’ll put down two seal coats and two top coats. However, water-based finishes will cure faster than oil-based products, with only about two hours needing to pass between each coat of finish depending on conditions. Typically, a day needs to pass between each coat of oil-based polyurethane, but again, this will depend on the conditions of the job site.

Safety Considerations When Applying a Polyurethane Finish

As with any product, be sure to read the labels of your finish so you take proper precautions. Polyurethane emits fumes that can be harmful if inhaled, so it’s important to work in a well-ventilated area. This may mean opening windows and doors, using fans, or even wearing a respirator.

You also want to avoid contact with eyes and skin, so wear protective clothing, including goggles and gloves. Once polyurethane dries, it can be difficult to remove, but if you do come in contact with it, immediately wash the area with soap and water.

Equipment Needed for Applying Your Polyurethane Finish

To apply your finish you’ll need an applicator.  Typically this is a lambswool applicator, a Duratool applicator, or a roller. With water-based polyurethane finishes, for best results, use a t-bar or roller. 

Instructions for Applying Your Polyurethane Finish

With oil-based polyurethane, finishes make sure the floor is prepped, cleaned, sanded, and tacked according to NWFA standards. Open time varies from product to product, but typically it’s longer for an oil-based poly finish compared to other options. 

Remember to always work in the direction of the wood grain on the second and third coats. Abrade the finish/floor in between coats, but do not buff the final coat! 

Usually you’ll need about 3-4 coats to fully protect the floor, one or two seals, and two finish coats. Make sure to keep a wet edge while applying with a t-bar. Each coat should be ready to re-coat in about 2-3 hours with a water-based finish and typically overnight for oil-based. The beauty of water-based finishes is typically you can recoat without abrading.

Watch How to Apply a Water-Based Finish

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