Polyurethane is a durable, long-lasting finish for hardwood floors and other wooden surfaces. It provides a resistant safeguard against all kinds of scratches and other damages, keeps your floors looking pristine, and tempers hardwood materials for years to come.
You should use at least 2-3 coats of polyurethane on wood floors. Depending on the type of polyurethane you decide to use, 2 coats may indeed suffice. However, if you are using a water-based poly, it is advised to apply 4 coats for an overall finished look.
You don’t need too many tools to apply polyurethane to your floors, and it largely depends on the type and brand you are using. All in all, it is a relatively cost-effective and enduring way to ensure that your floors look good for a long time. In the rest of this article, I will discuss the two main types of polyurethane, their benefits and disadvantages, coating procedures, and application tips.
There are two different types of polyurethane finish: oil-based poly and water-based poly. Both have their advantages and disadvantages, and which one you decide to use depends mainly on the nature and color of your floors.
There are several variables to consider when choosing which polyurethane you want to use; if you have darker flooring, it is generally advised that you use oil-based poly, as it has a yellowish tint that stains the wood, making it look darker and more appealing.
However, if you have lighter floors, such as maple, the best option for you is water-based poly. A water-based finish has no color and doesn’t stain the floor in the same way that oil-based poly tends to.
I will go through each type of polyurethane with tips on applying and general advice for coating procedures.
How Many Coats of Water-Based Polyurethane
Water-based poly generally needs at least 3-4 coats to be effective. Although there is some evidence suggesting that too many coats leads to a plastic-like finish, water-based poly is thinner than other types, so it needs a couple more coats to provide the same protection to your hardwood flooring.
There are several benefits to using water-borne poly:
- It is much better for the environment than oil-based polyurethane.
- It does not have a strong odor.
- It dries much quicker than any other type.
This means that you can easily apply each coat within just a few hours of each other, making the varnishing process very time-efficient.
However, there are a few downsides to using water-based poly: it can be slightly more expensive than other polyurethanes, with some suggesting that you will have to pay $1.50 more per square foot.
While the price can be off-putting, it is essential to remember that the better quality your poly, the better the finish will be, and the longer your wooden floors will last. If you use cheaper poly, or indeed the wrong type of poly, you will find that the finish might not be as desired.
It is essential to use more coats for high-traffic areas in your home, such as your hallways and kitchen areas. The more abuse your hardwood floors will endure, the more protection they need.
Here are a few tips on applying water-based polyurethane:
- Make sure you clean the floors with a hoover before applying the first coat. Remove any debris and cobwebs, and keep the area well-ventilated (without opening windows).
- Check for blemishes and flaws in the flooring before you begin. Taking this into account will ensure that your coating will be as perfect as possible.
- Use mineral spirits to thin the polyurethane before use. This protects from dripping and keeps the finish pristine. It also helps to prevent the area from becoming plastic-like in appearance.
- Use a synthetic brush to coat the corners of the area. You can use an ordinary roller for most of the space, but a synthetic brush allows for more precision.
- Make sure you sand and clean each layer properly once they are dry. Sanding prevents the finish from looking gritty and stops dirt and impurities settling in between the layers.
- Four coats of water-based polyurethane are advisable in most cases. If you do not apply enough layers, your finish will look poor. Remember, the more layers you use, the better your floors will look.
- For the last coat, do not sand it. Instead, use a clean, dry cloth to wipe down the dry surface. This will help the floor maintain a fresh look and optimize the finished product.
- Always use safety equipment such as masks and gloves. Using these can protect yourself during the process.
How Many Coats of Oil-Based Polyurethane
In general, if you are using an oil-based poly, it is advised to apply 2-3 coats for that perfect finish. Of course, it varies depending on the flooring type and polyurethane brand you use, but it is safe to say that 3 coats are the best way to go.
Oil-based poly has many benefits and is often the best option for darker flooring. It is denser than water-based poly, so you won’t need as many coats, and it is also a lot cheaper than its alternative. Because of its strength, it is also very straightforward to apply.
However, there are some disadvantages to using oil-based poly, such as its pungent odor and drying time. While water-based poly tends to take just a few hours to dry, oil-borne finishes can take up to 10 hours before one coat completely dries.
Additionally, it is advised not to put furniture over oil-stained wood for at least a week to prevent the finish from imperfections.
Oil-based poly is generally characterized by its yellowish tinge. This is an advantage to darker floors, but it can make it look cheap over time for a lighter foundation such as maple.
The best tools for oil-based poly include polishing pads. This type of applicator buffs and polishes as you use it.
You can always use a T-bar to spread the polyurethane for those stubborn corners. This pushes the liquid into corners with greater precision.
Of course, you will also need sandpaper of varying strength for oil-based poly, as you will need to sand in between coats.
Here are a few tips on applying oil-based polyurethane:
- Use the toughest sandpaper for sanding the hardwood floors before applying the poly. This will ensure a smoother finish.
- Stir the oil-based poly with a stick. Never shake the container, as this will encourage bubbles to form that will eventually be visible on the finished floor.
- Begin in the corners of the room and work your way to the exit. Try to plan your coatings with an option for exiting so that you don’t walk on the wet floors.
- As with water-based polyurethane. Make sure you sand in between each dry layer to ensure a perfect finish.
- Apply the poly with very thin coats. You can use mineral varnish to thin the layers.
- Oil-based poly takes a while to dry, so it is advisable to do one coat per day to ensure it dries thoroughly. Taking this into consideration, make sure the room is not too humid, and try to have a steady temperature at all times.
- Do not place furniture over the hardwood floors for at least one week. This will ensure that the foundations have ample time to dry.
- Make sure that you stay away from fire or direct heat sources. Oil-based polyurethane tends to be highly flammable, so bear this in mind when applying it to your flooring. Do not smoke around the finished product for at least 2 weeks.
- As stated, make sure you apply around 4 layers of the poly. Read the instructions before using.
One of the most popular oil-based poly brands is Zar, which you can find for a reasonable price. This is excellent value for money and suitable for residential spaces.
If you have a slightly higher budget and you are looking for a better finish, then Rust-Oleum’s high-gloss, quick-drying polyurethane is fantastic. It is undoubtedly more expensive than Zar, but it may indeed be worth it.
Rust-Oleum’s durable and tough quality ensures that coating is easy, and imperfections will not be as obvious.
While it is always prudent to double-check the manufacturer’s instructions before applying your polyurethane, it is advisable to put at least 3 layers of water-based poly and 4 layers of an oil-based poly.
In a commercial setting, wooden floors might need one extra layer due to high traffic levels, but 3-4 is recommended in a residential environment.