How to Apply Polyurethane to Wood Floors : Our Complete Guide

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So, you are having hard times with your unfinished hardwood floor. There must be some difficulties you’re facing frequently and wanna get rid of those.

Now, it’s obvious, you want to preserve your floor from scratches and unwanted liquid spillages. Also, your floor is getting an uglier appearance day by day. For this, you want to cover your floor with a protective shield.

Polyurethane can be a solution for your headache. It will work as a protective shield for your hardwood floor. Plus, it will add a stylish and amazing appearance to your floor.

Without any further intro, let me tell you about how to apply polyurethane to wood floors. Here, I am going to give you a bundle of steps and tips so that your floor finishing expedition can be simpler and smoother. 

Various Types Of Polyurethane Finishes

Most commonly, there are two types of polyurethane available in the market:

  1. Oil-based polyurethane: This type of polyurethane is long-lasting and stronger. It gives more protection against moisture, heat, or scratches than others.
  2. Water-based polyurethane: Even though water-based polyurethane is not so durable as oil-based polyurethane, it is widely accepted due to its lighter odor. Also, it gives colorless finishing and dries up faster.

You can also find three types of polyurethane finishes in terms of shininess.

  1. High-gloss polyurethane: This type of polyurethane gives an excellent shiny look after drying. This is a flexible, tough, and heavy-duty finish that is primarily used in industrial environments.
  2. Semi-gloss polyurethane: This finish gives less glossy look after applying. They are usually applied to doors, floors, furniture, etc.
  3. Satin polyurethane: This provides a medium to lower glossy look with a durable matte finish. Having a lower shiny look, it helps to hide the scratches and dirt on the floor.

Which Type Of Polyurethane You Should Prefer

You have to decide wisely which polyurethane will be suitable for your project, according to the requirements.

  • Water-based polyurethane takes less time to dry than oil-based polyurethane. Also, it has less odor than the oil-based version. As it is odorless, adequate ventilation won’t be important.
  • On the other hand, it is pretty easier to apply oil-based polyurethane. They are long-lasting, cheaper, and stronger than the water-based version. Because of higher chemical density, it will radiate toxic fumes. That’s why you will need a well-ventilated area when applying.
  • Besides, for the best result, the floor needs two or three coats of oil-based polyurethane finishes, whereas, it may require three to four coats of water-based finishes.
  • Water-based polyurethane gives a clearer look and won’t modify the color of the floor. Whereas, oil-based polyurethane alters the color of the wood and adds a warm glow.

Now, decide which one of these two meets your requirements.

Required Tools, Supplies For Applying Polyurethane And Their Costs

Once you’ve become certain about your required type of polyurethane, you need to get ready for gathering tools and supplies.

Here, I am trying to provide you a shortlist of necessary tools with their probable costs:

It’s Essential To Prepare The Floor First

Now, you’ve got the list of necessaries. Get the materials and get ready to prepare the workspace if you wanna have the best result. Follow the steps below:

Step 1: Sanding

Very crucial step to begin with. It’s vital that you sand the floor using an orbital sander machine with three differently leveled sandpapers. Start with 36-grit, then use 60-grit and 120-grit sandpaper sequentially.

Step 2: Vacuuming

You have to use the vacuum machine that is particularly designed for hardwood floors. Remove all the dust and residues from the room, especially check the corners for dust.

Step 3: Finalizing

Finally, check for other remaining dust and debris. Then, take a lint-free cloth and clean the floor using mineral spirits. Pay special attention to the corners and edges. Also, cover your baseboard with masking tape. This will prevent them from getting unnecessarily painted by the brush.

After these steps, you are allowed to go down to the main part: ‘applying polyurethane’.

Step By Step Polyurethane Applying Process

You’ve already taken a lot of preparations for the main event. Now, you are gonna receive a complete idea about how to apply polyurethane to wood floors. So, let’s begin:

Step 1: Stir the polyurethane carefully

Take a paint stick and start stirring carefully with it. Be aware of shaking the can, or it will let growing bubbles into the product. Having finished stirring, pour the polyurethane into a tray.

Step 2: Use a suitable brush

Take an 8″-12″ bristle brush for coating the floor. Firstly, you have to apply a thin coat with long and even strokes. Also, be careful about flooding the floor with polyurethane.

Step 3: Start applying form the corner side to doorway

In case, you may ruin the painting stepping onto it, start applying polyurethane from the corners and move towards the entrance door doing so. Remember to stoke the brush in the direction of the wood grain.

Step 4: Let the coat dry

You have to check instructions about how much time the polyurethane takes to dry up. Allow the floor to dry properly. Generally, it takes 4 hours to 12 hours.

Step 5: Sanding the floor for perfection

When the floor gets dry, sand the floor using 220-grit sandpaper. It’ll remove bubbles and other imperfections.

You may use soap and water for water-based and paint thinner for oil-based polyurethane to clean the floor.

Step 6: Thin the polyurethane for the second coating

Mix 10 parts polyurethane with 1 part mineral spirits (for oil-based) or 1 part water (for water-based). This will make the polyurethane thin. Thinning is done for avoiding bubbles.

Step 7: Start applying the second coating

Likewise the previous procedure, apply the second coat with thinned polyurethane and ensure even coating. Try to eliminate the uneven layers from the previous coating by applying this thinned polyurethane.

Step 8: Let the second coating dry

Don’t hurry to make it quick, rather have the patience to complete the process all in all flawlessly. Let the second coating dry according to the instruction assigned for the applied polyurethane.

Step 9: Take an abrasive pad to level the floor

You may bring a grade 0000 steel wool and rub the floor with it. It will be the perfect choice for removing flaws and leveling the floor. After rubbing the floor, wipe the floor again as before.

Step 10: Apply the Third and final coating

This time you have to apply the pure polyurethane for the finalization. And, don’t sand the floor this time. Instead, allow the floor dry for at least 24 hours after putting the final coat.

This finished coating should be remained intact for a long time. Wait for at least 1 week before repositioning your household objects on that floor.

Some Necessary Points You Need To Take Into Account

  1. First and foremost, never shake the can of polyurethane. Instead, just stir the product with a stick mildly.
  2. Execute the process in a well-ventilated area. Both oil and water-based polyurethane emit strong vapor, which will cause suffocating in a closed area.
  3. Don’t run the process in an outdoor area. Dust and flying bugs can ruin the floor during applying and drying.
  4. In case you are applying polyurethane on a sloped floor, there will be some drips and runs. For this, you may apply a thinner coat with the help of spray polyurethane finishes.
  5. After applying each coat within the whole process, inspect the floor through the light reflection. This will help you find the imperfections and you will be able to eliminate them in upcoming coatings.
  6. Use earplugs when sanding the floor. Also, use a respirator mask when applying polyurethane. Because they release a vapor, which is hazardous.
  7. Be prepared with the necessary tools first and take enough preparation before applying polyurethane to ensure the long-lasting finishing.
  8. Don’t rush when applying polyurethane. Give enough time to dry and clean the floor according to the provided instructions.
  9. You may practice a little bit on old scrap woods to test the proper functioning of a particular polyurethane finishing product.

My Concluding Verdict

Polyurethane can add an aesthetic and attractive appearance to your hardwood floors. Most importantly, it will act as a safeguarding shield for your precious wooden floors.

Applying polyurethane might be a tedious process for you. But, once you do it to your floor, it won’t deceive you in the long term. Rather, after a proper floor finishing work, and with regular maintenance work, your floor will stay shiny and durable for decades.

I hope, right now you have a good idea of how to apply polyurethane to wood floors after reading the above tips and steps. I wish you will soon apply these procedures to protect your unfinished floor from getting knackered in the future.


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