How to Apply Polyurethane for Floors? (6 DIY Steps)

A lot of DIYers struggle with polyurethane application on large surfaces like floors due but not anymore. Here is how to apply polyurethane on your floor.

Polyurethane application on a floor starts with proper vacuuming and cleaning of the floor to remove dirt. Then you need to sand the floor with a sander and apply primer paint if required. When the primer paint is dry, you can apply up to 4 coats of polyurethane on the floor using the best type of polyurethane applicator.

You should ensure to sand lightly between coats of polyurethane using 320-grit sandpaper. Also, allow the polyurethane to cure for at least 3 days before normal use is resumed on the floor.

This post explains a lot more about applying polyurethane on your floor including the step-by-step expert method to complete the task. Let’s dive in.

Is Polyurethane Strong Enough To Protect Floors?

Polyurethane is strong enough to protect floors including hardwood floors. Polyurethane has a top layer made of urethane plastic, a compound that is flexible and waterproof.

The urethane top layer will protect the floor from water damage, heavy furniture, and even high foot traffic. The flexibility of the polyurethane finish also means that it will withstand heat and cold well making the finish temperature friendly.

Polyurethane floor finish contains a high volume of urethane (plastic-like compounds). The presence of urethane makes the polyurethane finish mimic the qualities of plastic. This means that polyurethane can expand and contract based on temperature changes.

The hard plastic material on the top layer of the polyurethane also makes the floor strong enough to withstand constant use, heavy furniture, and heavy foot traffic.

So, what type of polyurethane is best for floors? Let’s find out.

What Type Of Polyurethane Should You Use On Floors? (Oil or Water-based)

What Type Of Polyurethane Should You Use On Floors?

There are two types of polyurethane; oil-based polyurethane and water-based polyurethane. Both types of polyurethane are good for your floors but let’s do a quick comparison between both finishes to see which is better.

Clarity

Polyurethane is known to produce a clear finish that reveals the tone and grain of the wood underneath. Water-based polyurethane retains this clear finish longer than oil-based polyurethane.

After a while, oil-based polyurethane will begin to yellow or have an amber tone while water-based polyurethane will remain clear.

So, if the clarity of the finish is what you want on your floor, you should go for water-based polyurethane. If you don’t mind the yellow tint of oil-based polyurethane, you can go for it too.

The Dry Time

Water-based polyurethane dries faster on floors than oil-based polyurethane because water dries faster than oils. On average, water-based polyurethane will cure in about a day while oil-based polyurethane will take up to 3 days or more to dry on your floor.

Durability

Since oil-based polyurethane dries slowly, it has more time to cure and harden so the finish is more durable on your floor than water-based polyurethane. Water-based polyurethane is known to chip and peel after a few years while oil-based polyurethane will not chip.

Cleaning and Maintenance

Oil-based polyurethane doesn’t require as much maintenance as water-based polyurethane. This is because stains on oil-based polyurethane often blend into the finish. The amber tone that develops on oil-based polyurethane makes the floor hide stains easily. So you won’t need to take on much cleaning.

Water-based polyurethane on the other hand highlights stains on the floor due to its transparent finish. So with water-based polyurethane, you’ll be cleaning stains more often.

However, you should know that water-based polyurethane is easier to clean than oil-based polyurethane. While most stains on water-based polyurethane can be wiped with a rag and soap mixture, you’ll need solvents to clean oil-based polyurethane since stains blend and hide well in the finish.

Number of Coats Needed

You need 2 -3 coats of oil-based polyurethane on your floor. Water-based polyurethane requires up to 5 coats for proper coverage, especially on a wood floor.

Final Verdict: Overall, water-based and oil-based polyurethane are both great choices on your floor but oil-based polyurethane is a better fit. Oil-based polyurethane requires fewer coats and is more durable than water-based polyurethane.

What Is The Best Applicator For Polyurethane On Floors?

The best applicator for water-based polyurethane on the floor is a synthetic bristled paintbrush or a microfiber paint roller. The best applicator for oil-based polyurethane is a lambswool paint roller or a natural-bristled paintbrush.

It’s also possible to spray both types of polyurethane on a floor but this will take a certain level of expertise as you’ll need to thin the polyurethane, prime the paint sprayer, and spray correctly to avoid over-spraying.

Painters also use applicator pads to apply polyurethane on floors. Applicator pads are usually fitted into long poles that allow you to cover larger areas.

Next, let’s check out how to apply polyurethane over a wood floor.

How To Apply Polyurethane To Wood Floors?

Applying polyurethane over a wood floor isn’t a difficult task as long as you know the right steps to follow. Luckily, this guide will show you how to apply polyurethane over a wood floor in just 6 easy steps. But first, we’ll need a few tools and supplies:

  • A vacuum
  • 320-grit sandpaper
  • A floor or orbital sander
  • Clean rags
  • Mineral spirits
  • Polyurethane paint applicator
  • Water or oil-based polyurethane
  • Wood filler
  • Primer paint (optional)

Here is a 6-step guide to applying polyurethane on a wood floor:

1. Prep The Wood Floor

Prep The Wood Floor

The first step is to vacuum and clean the wood floor. This is done to get rid of debris and filth on the wood floor before the polyurethane is applied. You can also sweep the wood floor if you don’t have a vacuum. The main aim is for the wood floor to be clean.

After sweeping or vacuuming the floor, you should use a clean rag to wipe the floor – you can also use a mop. If there are stubborn stains on the floor, you can get rid of them using mineral spirits or rubbing alcohol.

You should know that dents, holes, and gouges in the wood should be repaired with wood filler. If the wood is severely damaged, it’s best to replace it. If you don’t repair or replace the wood, the damages will be seen through the transparent polyurethane finish and this will make your finish look amateurish.

2. Sand The Wood Floor

Sand The Wood Floor

When the wood is clean and repaired, the next step is to sand. You can sand the wood floor using 150-grit sandpaper and then work your way up to finer grit such as 240-grit sandpaper.

You can also use sanding pads or sanding blocks if either is more comfortable for you. You’ll need a floor or orbital sander because of the large nature of the floor. But if it’s a small floor, you can sand manually. After sanding, ensure to remove dust.

3. Prime The Wood Floor (Optional)

Prime The Wood Floor

This step is not compulsory as you can apply polyurethane to bare wood. However, if the wood seems old or patchy, you should put a primer coating on it.

Also, if the wood doesn’t look fine or it has stained spots, you should apply a coat of polyurethane primer paint to cover the spots. You can apply the primer paint using a paintbrush or a paint roller. Ensure to allow the primer coating to dry fully before laying the polyurethane.

4. Apply The Polyurethane

Apply The Polyurethane

The next step is to apply the polyurethane to the wood floor. You’ll need to apply just a coat of polyurethane first because each coat needs to be strong and hard enough to support the next coat.

You can use a paintbrush, roller, applicator pad, or paint sprayer for the first coat. Ensure to cover the entire floor with the first coat of polyurethane. Tight corners on the floor can be reached with an angled paintbrush.

Ensure the first coat is dry enough before a second coat. When the first coat is dry, you can recoat the polyurethane. On average, it takes about 3 hours for water-based polyurethane to dry enough for a recoat while oil-based polyurethane takes up to 6 hours.

You should know that the type of finish also matters. For instance, a high-gloss polyurethane finish regardless of the type takes longer to dry than a matte or flat polyurethane finish.

Always check the manufacturer’s instructions for the proper dry time. While waiting for the polyurethane coat to dry, ensure to store your painting equipment properly so they don’t get clogged with paint.

5. Recoat The Polyurethane

Recoat The Polyurethane

After the first coat has dried, you need to sand it with super fine sandpaper like 320-grit sandpaper. The sandpaper will smoothen the first coat and remove dust nibs and bumps. This will allow the next coat to stick properly. You need to sand between each coat of polyurethane.

After sanding, you can apply a recoat the same way you applied the first coat. For water-based polyurethane, you need 4-5 coats on the floor. For oil-based polyurethane, you need 2-3 coats on the floor. You don’t need to sand the final coat of polyurethane.

6. Leave To Dry

Leave To Dry

After applying the polyurethane coats, leave the finish to dry. You should check the manufacturer’s instructions for the dry time of the polyurethane.

Generally, it takes a while for polyurethane to fully dry on a floor. Water-based polyurethane dries in less than 6 hours but it will take at least 24 hours for the water-based polyurethane to fully dry or cure on the floor.

Oil-based polyurethane takes longer to dry and can take up to 24 hours to dry but you should let the oil-based poly cure for at least 3 days.

You should wait until the polyurethane has cured before normal usage and cleaning are resumed. It’s only when the polyurethane cures that it reaches its full potential and becomes waterproof.

Do You Have To Stain The Floor Before Applying Polyurethane?

You don’t have to stain the floor before applying polyurethane because polyurethane can be applied on a bare wood floor. However, you should know that staining the wood floor before polyurethane application adds color and beauty to the wood floor.

Polyurethane is a transparent sealant meaning that the finish has no color or dye. So if you apply polyurethane on your wood floor, the polyurethane will not add any color.

Instead, the transparent polyurethane finish will reveal the texture and wood grain. If that’s what you want, then you can apply the polyurethane directly to the bare wood floor. However, if you want color on the finish, then you need to stain the floor before applying the polyurethane.

How Soon Can You Walk On Floor After Applying Polyurethane?

You can walk on a polyurethane-painted floor as soon as the polyurethane paint has cured (dried fully). It takes at least 24 hours for polyurethane to fully dry or cure but it’s advised to leave the polyurethane for at least 2 days before walking over the floor finish.

When the polyurethane cures, it means that it has completely dried and it’s at this stage that the polyurethane reaches its full strength and becomes waterproof.

This is when you can walk on the polyurethane freely and it takes between 24 hours and 72 hours (3 days) for polyurethane to cure on a floor. If you walk on polyurethane before it cures, you’ll smear the finish and damage the flooring.

How Long Does Polyurethane Last On Floors?

Polyurethane lasts between 5 years and over 20 years on floors. The durability and strength of the floor make it stand up well to high traffic and busy areas without showing signs of damage.

However, you should know that how long the polyurethane finish will last depends on the condition of the floor, the type of floor, and the environmental conditions around the polyurethane finish.

For instance, if you installed polyurethane on your front deck and dining room floor on the same day, the polyurethane on your front deck will not last up to the polyurethane in your dining room.

This is because the polyurethane on the front deck will also be exposed to dirt, high foot traffic, UV rays from the sun, rainfall, dust storms, and the likes – all of which will damage the polyurethane finish quickly. The polyurethane in your dining room will not be exposed to these factors and as such will last longer.

Alternatives To Polyurethane On Floors

Here are other alternatives to polyurethane just in case you don’t fancy a polyurethane finish:

  1. Varnish – There are different types of varnishes that work on floors including acrylic varnish, oil varnish, exterior varnish, and the like.
  2. Wood oils – Wood oils like Tung oil, Linseed oil, and Danish oil will protect your floor and give it a nice luster.
  3. Lacquer: Lacquer is very similar to polyurethane in terms of durability and protection but you need to pick the right type for floors.
  4. Shellac: Shellac is another alternative to polyurethane that is hard and strong. Shellac also has a natural makeup so it’s safe to use on all floors including kitchens and dining areas. You should know that shellac doesn’t have weather resistance.
  5. Wax: You can also use wax on your floor but you should know that you’ll need to buff the wax regularly to retain the finish.

Final Words

In summary, you can apply polyurethane on any type of floor easily as long as you follow the right steps and use the right painting equipment. Remember to vacuum and clean your floors before applying polyurethane.

You can use either oil-based or water-based polyurethane on a floor but oil-based polyurethane seems to be more durable.

You should sand between coats of polyurethane with 320-grit sandpaper and allow each coat to dry enough before a recoat. Finally, allow the polyurethane finish to dry for at least 3 days before cleaning and using the floor.

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