How to apply polyurethane on wooden floors: A complete guide

by Apr 26, 2021Cleaning


To ensure that your wood floor lasts as long as you want, it is important to apply a finish after installation by knowing how to apply polyurethane to wood floors. Polyurethane provides a layer of protection for wooden floors.

Hardwood floors are probably the best choice when choosing a type of flooring. Aside from giving the home an elegant look, hardwood floors match almost any type of decor, are easy to maintain and even increase the value of the property.

This post is a guide to applying polyurethane to newly installed hardwood floors. It is also relevant for those who want to refinish their wood floors or to cover wear and tear in old floors when it is just not polishing hardwood.

Varnishing of wooden floors
Application of finishes on wooden floors

Water-based vs. Oil-based polyurethane comparison table

There are essentially two types of polyurethanes; water-based and oil-based.

The decision on a type to use depends largely on your situation, preference and the area you want to apply the finish. Below is a comparison of both types of polyurethane. Using these points, you can determine what works best for you.

Variable Water-based polyurethane Oil-based polyurethane
Drying time Shorter drying time (2-3 days) Longer drying time (4-5 days)
Color and gloss Less gloss More shine
Necessary coats 3 layers for high quality product

4-5 coats for lower quality product

3 layers required
Technical know how Often requires work experience as it dries faster and gives less time to correct mistakes It takes longer to dry and allows correction by inexperienced users
Durability Lower quality products can last up to 4-6 years, while high quality products can last up to 10 years Lasts up to 10 years and over
Cost More expensive Cheaper
Volatile organic compounds Contains more volatile organic compounds Has less volatile organic compounds

Both water-based and oil-based polyurethane have their unique properties and benefits. The comparison made will guide your choice of choosing one depending on the intended use and purpose.

Furthermore, water-based polyurethane contains a large amount of volatile organic compounds, and as a result, it is restricted to use in some buildings for safety reasons.

Here is a short video highlighting the differences between water based polyurethane and oil based polyurethane.

Watch video: Oil and water based polyurethane

Tools needed to apply polyurethane to hardwood floors

When applying polyurethane to hardwood, some tools are needed to perform this task. The tools that are used for use and which also ensure safety are:

  • Sealing of polyurethane
  • Brush for bristles (natural bristles for oil-based; synthetic bristles for water-based)
  • Stick cloth
  • Paint tray
  • Abrasive brush
  • Masking tape, steel wool and sandpaper
  • Stirring
  • Safety equipment (goggles, gloves, respirator)
  • Vacuum
  • Broom and mop

Necessary ingredients

While applying polyurethane to hardwood floors, here are the things you need:

  • White vinegar
  • Mineral spirits
  • Soap
  • Water

Safety tips when working with polyurethane

Polyurethane contains some chemicals but does not pose a danger when used safely. Therefore, it is important to note some of these safety tips before applying polyurethane:

  • Wear a respirator / face mask: When working with heavy vapors such as those found in the oil-based polyurethane, it is important to use a respirator to reduce the number of inhaled vapors.
  • Provide ventilation: When working with polyurethane, it is important to ensure that the work area is well ventilated to facilitate breathing. It is recommended to keep all windows and doors open in addition to wearing a respirator or face mask.
  • Wear gloves and goggles: Polyurethane should always be applied with a brush, but gloves are still very necessary to avoid skin contact. Similar goggles prevent drops or splashes of polyurethane from entering the eyes.
  • No smoking: The content of polyurethane is highly flammable; Therefore, it is important to ensure that no one smokes around the work area and that there is no open fire. A fire extinguisher must always be stored around the work area.
    Extra care must be taken with water-based polyurethane as it contains more volatile organic compounds.
  • Proper cleaning: After work, make sure all polyurethane cans are disposed of properly to reduce health and fire hazards. There is often a designated disposal option for this type of can, safety should be considered during disposal.
Wooden carpentry gloves
Man properly protected while working

How to apply polyurethane on hardwood floors

Now that you have the necessary material and have ensured safety, you can protect your wooden floors by adding polyurethane in these simple steps.

Step 1: Prepare the floor

Unless the floor is new and pre-sanded, it is important to sand it with three different types of sandpaper; 36-grit sandpaper, 60-grit paper and 100-grit sandpaper in that order. This removes any imperfections and ensures that a smooth surface is ready.

Next, it is important to ensure that the floor is properly clean. This can be done using a vacuum cleaner for wooden floors or broom and a mop with water and white vinegar (ratio 10: 1). Pay attention to the corners of the room during cleaning.

After doing so, the next thing is to wipe the work area down with cloth; this will ensure that any remaining dust or dirt is removed before working on the floor.

Finally, it is common to use polyurethane to accidentally brush it on the base plates, and it is therefore important to apply masking tape to protect the base plates.

Step 2: Stir the polyurethane

Due to packaging, the components of polyurethane can have an uneven composition and give a rough texture when used.

One of the worst things to have after applying polyurethane on hardwood floors is the appearance of bubbles. To avoid this, it is important to stir the polyurethane properly before use. Avoid shaking the can as this will create more bubbles in the can.

Step 3: Apply with the brush

After stirring, pour the polyurethane into a paint tray. Use the brush to apply a thin layer of polyurethane to the wooden floor in long even strokes. Do not go over the same place several times to avoid occupying one area more than the rest.

During coating, it is best to start in the farthest corner of the room instead of the entrance to avoid stepping on the surfaces where you have applied the polyurethane when leaving the room.

Step 4: Let the coat dry

After applying the first coat, it is important to wait for it to dry completely. It takes about 3 hours to dry mostly water-based polyurethane, but the oil-based option takes longer than that.

Step 5: Sand again

Use 220 grit sandpaper, sand uneven coats, bubbles and other imperfections, and make sure you slip along the grain instead of against it.

Step 6: Wipe down with adhesive

Use another cloth with soapy water for water-based polyurethane or mineral spirits for the oil-based polyurethane, and dry hard wood floors thoroughly to remove all dust from sanding.

Step 7: Thin polyurethane

Add water to the water-based polyurethane or mineral spirits to oil-based polyurethane to dilute to another coating. It must be diluted to a ratio of 10: 1 (10 parts polyurethane to one-part water / mineral spirits. Stir well and pour into the paint tray.

Step 8: Apply the diluted polyurethane

Using the same method as before, apply thin polyurethane to the wood floor.

Step 9: Let it dry again

Again, wait for the new coat to dry before you can continue working on it

Step 10: Brush with the abrasive brush

Use the abrasive brush to smooth out imperfections and ensure that the entire coated area is leveled.

Step 11: Wipe down

Wipe the floor to remove dust and dirt that may have accumulated during brushing, using the same method as before.

Step 12: Apply Final Coat

Then re-coat the wood floor and wait up to 24 hours for water-based polyurethane and 72 hours for oil-based polyurethane before starting to walk on the finished floor.

Here is a short video explaining how to apply polyurethane to hardwood floors.

Watch video How to apply polyurethane

Maintenance of your finished floors

After moving into your new (new floors) home, you need to maintain it so that the work done lasts a long time. While the polyurethane will take the greatest possible load, there are some tips to ensure you do not need a re-finish anytime soon:

Clean up spills immediately

To avoid stains on the floors, be sure to wipe up any debris immediately before it can seep into the wood. Use dry or slightly damp cloths to wipe up spills on hardwood floors. Using wet or steamed mops will damage the wood over time.

Sweep daily

Use the appropriate brooms for hardwood, and make sure you sweep daily to remove dirt and dust. This prevents staining of hardwood.

Vacuum the floors every week

Using suitable vacuum cleaners for cleaning the floors every week removes dirt found in the slots on the floor that the brooms may not pick up, or you can also buy a Roomba for your hardwood floor.

Use wood floor cleaner every month

There are different types of hardwood floor cleaners, find the one that suits you and make sure you use it every month

Use furniture cushions

Furniture cushions prevent wooden floors from getting scratched on them, which is one of the problems that hardwood owners face. Furniture cushions should be added to the legs of chairs, tables, sofas and so on.

Finish every 5 years

Although your hardwood may not need varnishing, it is still recommended to varnish it every few years to protect it from excessive damage.

Extra tip

  • For those who want to finish their wood floors, it is best to use the same material that was used during the first finish, or remove the first finish completely before applying a new one.
  • You can coat your wood floors as much as you want using water-based polyurethane. With the oil-based option, however, it is best to do it only three times to keep it neat.
  • It is advisable to leave the house for as long as necessary when planning to use oil-based polyurethane on your hardwood floors to avoid inhaling the fumes from the house members.
  • After using the oil-based polyurethane, wait a few days before moving into furniture, and also ensure proper ventilation for the first few weeks.
  • Keep the temperature in your home between 60 and 80 degrees Fahrenheit to maintain your hardwood floors.

Extra caution

  • Polyurethane should be used with caution, apart from the basic precautions when using safety equipment such as gloves, googlers and respirators. If you have breathing problems, it is not recommended to perform the application yourself.
  • Family members with respiratory distress should also not be allowed to be at the site of application of polyurethane. It can also react and cause skin irritation. Proper and protective clothing should be worn in addition to gloves to prevent contact.
  • Due to the flammability of polyurethane, it must be kept away from open flames and anything that may ignite or start a fire.

What can you expect?

Although the steps described in this post seem easy, you may find some processes a little difficult to do alone. It is therefore advisable to ask for help from either a professional, an experienced DIYer or adult family members, as taking the job on your own will make it slow and tiring.

It is perfectly fine to seek professional help if you do not seem to get an even flooring.

Also, the quality of polyurethane means something that is often low and high quality polyurethane. Choosing one usually depends on your type of wood flooring, it is important to get one that fits your floor to avoid damage.

What is your experience with adding polyurethane to hardwood floors? Let us know below by dropping a comment, and also remember to share this post with those who need help adding polyurethane to hardwood floors.

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