Why Sand Between Coats of Polyurethane: Full Staining Guide

Did you recently finish installing the hardwood floor at your home? After installing, are you thinking it’s time to relax now?

Wait, your job is not yet completed. Still, you have some unfinished work. It is time to give a coat of polyurethane. Otherwise, all your hard work will go in vain. Would you love to let it happen? No, right?

Well, I believe many questions popped up in your mind.

Why should I use polyurethane on my wooden floor? Do I need to sand between coats of polyurethane? What type of product do I need to apply?

Wait, wait, mate! Take a breath. Shake your hands with me. I am going to quench all your thirst regarding the above questions in the below sections.

Stay with me until I finish the article.

Sand Between Coats of Polyurethane

Sand Between Coats of Polyurethane – on Floor & Wood Furniture:

What type of product do I need to use?

Before starting, you need to make sure you have decided about the type of polyurethane that you are going to use on your hardwood floor.

You will get oil-based and water-based polyurethane in the market. Whether you have a traditional or engineered hardwood floor, both types will protect your hardwood floor without any concern.

But you need to know the difference between oil-based and water-based polyurethane, before making the final decision.

Must Read: Best Finish for Wood Kitchen Table

Water-based Polyurethane

water based polyurethane
water-based polyurethane

It is a clear solution that will not change the original colour of your hardwood floor. Compared to other solutions, it is thinner and dries quickly. After applying water-based polyurethane, you can walk over your floor within 10 – 12 hours.

Moreover, this solution doesn’t contain harmful toxins like VOC’s. As a result, it becomes a less flammable solution. Even no emission of robust odor happens in this solution. One of the best features of water-based polyurethane is, during cleaning, you will not face any hassle. All you need to do is, use soap and water and get an amazingly clean floor.

But the drawback of this polyurethane is, it is pricier and less durable. As it is encompassed with fewer solids, you need to apply several coats of water-based polyurethane on a hardwood floor.

Once you apply water-based polyurethane on your floor, you need to reapply the process after 2 years.

Oil-based Polyurethane

Oil based Polyurethane
Oil-based Polyurethane

Compared to water-based polyurethane, this solution is thicker and takes much time to dry. And the emission of odors and fumes happen from this solution.

Also, oil-based polyurethane improves the look of hardwood and gives it a shiny and glowing look.

It is cheaper than water-based polyurethane, and providing several coats is unnecessary.

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What Materials Do I need to Use while Applying Polyurethane?

It is time to take your notebook and pen. Because the list is more extensive and if you don’t write it down, you will forget for sure. And worry less, because all materials are inexpensive and easily purchasable from local stores.

Once you have decided on the type of polyurethane, the next question is which brand. It is significantly essential to pick a brand that is upfront about chemicals and storage requirements. Also, choose a brand that provides telephone support in case you need any advice.

a) Orbital Sander: If you own an orbital sander, that is good. But if you won’t, surf in your nearest local improvement store and rent an orbital sander. It is recommended to purchase several levels of sandpaper. You can go with 36, 60, and 120 grit level sandpaper.

b) Sandpaper: For between coats, it is mandatory to purchase 220 grit sandpaper and along with a pole sander. If you think purchasing a pole sander will be unnecessary because you can make it using a broom handle and a sanding block.

c) applicators and brushes: To apply urethane, you will need synthetic applicators and brushes, which are specially designed for applying polyurethane. To apply polyurethane efficiently in the corners and door jambs, purchase a T-bar.

Note down, T-bar is suitable for water-based, and a roller works greatly with oil-based.

d) Other: Other necessary tools are respirator, masking tape, hand gloves, mineral spirit. Don’t forget to note down so that you can remember.

Preparation Time

Now, you have done the shopping; you need to prepare the workstation. You should consider this part as the deadliest and vital in the whole process.

Now, You have to start with cleaning your hardwood floor. Look at every corner to clean, wipe away dust and dirt. If the room consists of a window, open it up and let the airplay in your room.

Once you have cleaned everything, now you need to start sanding the floor. If you are unaware of the operating procedure of a sander, open your browser on the computer or smartphone, visit YouTube, and look for tutorials. Use the roughest paper first.

Remember, not to sand one area too much. Thus your floor will become too rough, which is not suitable for applying polyurethane.

Are you wrinkling thinking whether I need to sand between coats of polyurethane on floors or not?

In my opinion, it is required.


Because polyurethane creates a coat of polymer over the hardwood floor, it will need an inter-coat scratch minimum of one time during the process.

If you are going to use polyurethane in a large area, it is advisable to sand the floor with rough sandpaper. And if the area is small, you can use a pole sander or a short sanding paper.

So, I believe you have got your answer to the question Do I need to sand between coats of polyurethane? Isn’t it?

Well, once you finish cleaning the floor, inspect the floor again to reconfirm.

When you are all done, vacuum the floor to wipe away all the dust (if anything is available). Also, clean the hardwood board using a soft and clean cloth. You can apply mineral spirit with the cloth to clean the board.

How to Apply Polyurethane on Hard Wood Floor  – The Process:

Process for Applying Polyurethane hardwood floor

Now everything is set up for the final round.

Firstly, take the polyurethane can and stir it well with the paint stick. Never give a shake to the can. If you do so, you will end up with air bubbles in your finishing.

Secondly, Dip the paintbrush or applicator to the polyurethane and tip-off if any excess is there. Start applying the poly from a corner. To ensure an even coating, provide long covering strokes.

Thirdly, Check out for any type of dripping spot. You need to correct these before the polyurethane gets dried. Once you provide the first coating, give it a rest for a few minutes. And then double-check whether you have missed any areas or not.

Fourthly, Let the polyurethane dry thoroughly before you continue the same process. Make sure; you have read the manufacturer’s instructions to learn about the drying time.

Fifthly, And you can sand any types of drip or imperfection after the floor gets dried fully.

6th Step: If required, you can repeat more coating. But remember to give a rest between the coating. The majority of the hardwood floors need 2 – 3 levels of coating to get a beautiful finish.

Before you say QUIT to the application process, it will be best if you contact your floor manufacturer.


Question: Maximum how many coats of polyurethane do I need to apply on the hardwood floor?

Answer: Applying one coat of polyurethane will never give you a beautiful finish for sure. Multiple coating is necessary, and your hardwood floor will undoubtedly look amazing.

Question: Is polyurethane safe to use?

Answer: No doubt, polyurethane is safe.

Diisocyanates, along with polyols, are used to make polyurethane, and both of these chemicals don’t have any impact on the environment. Adequate researches have shown that polyurethanes are safe and secure.

Question: Why do I need to use polyurethane?

Answer: You will get a mouthful of benefits applying polyurethane on your hardwood floor.

  • Polyurethanes are remarkably harder and flexible enough to resist any type of impact. Also, it doesn’t allow any scratches on the floor due to the same characteristic.
  • Your wooden floor will be protected from moisture, bacteria, mildew, foot traffic, and all types of impact.

Question: Without shaking the polyurethane can, is there any other reason for getting bubbles in the poly?

Answer: You will get bubbles if

  • The wood is moisture enough.
  • If the applicator or brush comes with poor quality.
  • Over brushing the polyurethane.
  • You use the roller as an alternative to a brush.

Overview of the full process

So, let’s give a simple overview of the process:

  1. Clean the hardwood.
  2. Sand it down.
  3. Confirm no dust and dirt is left behind.
  4. Apply the first coat and give it a rest to dry.
  5. Now, Apply the 2nd coat.
  6. Then Apply the 3rd coat.
  7. Correct any types of imperfections with a razor or sandpaper.

Wrap Up:

Applying polyurethane is not a complicated task, but it is a tricky one. To get an excellent finish, you need to have a grouping of knowledge and ability.

If you do the improper brand selection, no preparation before applying the polyurethane, you will end up with a mess coating. It will be best if you do practice on scrap wood. Thus you will be familiar with the technique. One point that I want to remind you again, before applying polyurethane, make sure the floor is properly cleaned and dried. Best of luck!

Last Updated on August 27, 2021 by Rogers Weber

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