How Many Coats Of Polyurethane (Too Many Coats Can Damage Wood)

how many coats of polyurethane

So, how many coats of polyurethane you ask? Apply 3 to 4 coats of water based polyurethane on wood wait 2 hours in between layers. Apply 4 coats of oil based polyurethane on wood and wait 8 hours in between. Don’t apply too many coat and you should be just fine.

Have you ever wondered how woods and furnishes have some shiny finish varnish protecting them from scratches, knocks, and weather? Polyurethane varnish is the key to giving your wood a durable coat that adds the final finish to your furniture or floor’s wooden surface. Knowing how many coats of polyurethane and types of polyurethane can help you find the best polyurethane for a smooth and durable material to high-quality, long-lasting polyurethane finish.

The types of Polyurethane come from its application. Although they may vary depending on the material, they are still used to improve the quality of the material from aesthetic to durability.

The sleek finish of Polyurethane in your materials is dependent on how many coats you applied to the material. Learn these tips and tricks to have the perfectly smooth, durable material coated with Polyurethane.

Uneven Layers

More layers of polyurethane coats can cause uneven layers. You can fix this by sanding the uneven finish using sand-paper to make it even before reapplying polyurethane.

Yellow Look Finish

Too many coats of polyurethane give a yellow look to the material, and over time it will grew more yellow due to oxidation. Scrape the old layer that contains a yellowing finish. You can use dry or wet sand paper. Reapply the polyurethane to have the desired finish.


If too many coats are applied, then the coatings will be thicker and will be soft that results in peeling. If the layer has shown peelings from overcoating, get a razor blade, scuff the peel away, sand for a better finish, and then reapply polyurethane.

Longer Waiting Time

It will take time if more coats are layered since it will need more time to dry each layers before reapplying polyurethane coats. Follow the recommended coats of polyurethane on materials to avoid damage done to the product.

Use polyurethane on bare wood and furniture as final touches and sometimes fixing wood stain. Being greedy in adding more coats can damage your materials instead of protecting it. Avoid damage to your materials by following the recommended coats in the material and fixing the damage to help increase its durability.

Polyurethane is a chemical reaction from a chemical resin polyol that serves as the base and a curing agent diisocyanate as its hardener. Polyurethane resin offers versatility in various uses such as for packaging, automotive, apparel, woods, and many more.

In totality, poly coating helps in improving the quality of the material by adding more protection from the external environment while leaving comfort from the eyes and the body. Start protecting your materials by applying polyurethane.

Research proves that even the presence of nail polish, alcohol, bleach, vinegar, mouthwash, and dishwashing liquid did not affect the quality of polyurethane applied in wooden surface, even with a thin coat.

Woods without final touches can be annoying and prickly. It’s more prone to abrasions in weather conditions reducing its quality over time. Its natural beauty is exposed to moisture and can make it an entry point in mold growth.

Protects From Weather

It creates a barrier that is abrasion-resistant and weather-resistant. Weathering elements and tears are left on the surface because of the glossy finish of the wood.

Resistance In Chemicals

Be it nail polish remover or spray paint, its resistance to protecting the wood from chemicals is superb. Even chemicals from bird droppings and bacteria cannot penetrate and affect the quality of wood.


Polyurethane has a diverse range of purposes in different industries, such as apparel in the production of fabrics, floorings in coating and cushioning floors, and insulation for balancing the temperature of your home.

Improves Durability

Preserving its quality is significant in improving its durability. The additional protection from the coat makes it possible for high-quality wood with long-lasting durability.

Start protecting your wood from the harsh conditions of the external environment. A coat of Polyurethane can increase the lifetime of your wood, better aesthetic, more protection to your furniture.

The types of Polyurethane come from its application. Although they may vary depending on the material, they are still used to improve the quality of the material from aesthetic to durability.


Thermoplastics used in construction, automotive, and footwear applications. It can withstand temperatures and make them elastic, flexible, and resistant to abrasion. It is usually melted first before it is cooled for remodeling. In footwear, it is applied through injection in soles for extended durability.


Binders are used in binding materials and for strong adhesion between substances commonly used in housing components. It can be applied by getting a small part of a binder then applying it to a material. Its cohesion will not wear even by the external environment because it uses the water in humidity to fully cure in approximately 24-48 hours.

Flexible Polyurethane Foams

It is used for cushioning in commercial and consumer products that enhance the comfortability of the product while providing a protective material that increases its durability. The foam is created in many shapes and firmness, so applying it to commercial products is easy. In using this foam, apply a thin polyurethane coat and wait for two minutes before adding the topcoat and second coat, which will speed the cure for the following layers.

Rigid Polyurethane Foams

Mainly used for insulation, it is the perfect foam for residential properties that keeps molds away from your home build, controlling moisture of the foam. This type of polyurethane is applied in the roof and wall insulation, insulated windows, door, and air barrier sealants. After application through spraying, it rapidly expands due to the moisture in the air. It bonds well in surfaces because of its adhesion.

Reaction Injection Molding (RIM)

Polyurethane molding into a specific shape for computer and automotive parts helps the product be heat resistant and have high strength even with little weight. In applying these molds in products, polymers are injected and mixed in under high pressure before injecting into a mold under low pressure for curation.

Adhesives, Sealants, And Elastomers

Using this type of polyurethane increases the product’s durability by sealing and covering it that offers protection from external elements and gives shine to the material for added beauty in the final product. polyurethane adhesives application requires clamping or pressing the materials together for five minutes before being fully curated at 24 hours. polyurethane sealants need three to twelve hours before drying and 24 hours to cure. In contrast, polyurethane elastomers are molded into shape, which takes up to 24 hours to dry.

Waterborne Polyurethane Dispersions

These water-based solvents are for coatings and adhesives. These are eco-friendly since it doesn’t produce hazardous air pollutant and a harsh organic compound. It is applied by using water as its primary solvent and is dried at ambient temperature.


Polyurethane coatings are applied to woods or materials to help it protect from deterioration from external environments like corrosion, weathering, and abrasion. Water-based Polyurethane is recommended for retaining the color of the wood with just two or three coats. Oil-based can enhance the rich amber tone of the wood with three or four coats and offer excellent oil finish. The mix of water-based and oil-based provides wood a fast-drying action that gives the wood a warmer shade.

The overall quality of the product will depend on how you will utilize these polyurethanes in your materials. Improve your understanding in your home by knowing the versatility of Polyurethanes. Use its flexibility and cost-effectiveness in the durability of your materials and products.

My 2¢

Polyurethane has a lot of benefits in boosting the durability of the materials, and it has the flexibility and versatility for it to be applied in everyday materials. Add beauty and comfortability to your home by using polyurethane.

In 2017, 60.5 billion USD of polyurethane materials were consumed worldwide, proving that polyurethane can improve the quality of living through its durability and the offers that it projects.

Over time, polyurethane can become a standard in improving the quality of your materials and even furniture so start learning more about polyurethane.

How many coats of polyurethane? In short, 3 to 4 coats (2 hours dwelling time per coat) of water based polyurethane and 4 coats (8 hours dwelling time per coat) of oil based polyurethane on wood.

Read my guide on best way to mark tools and how to cut straight using reciprocating saw and leave your feedback. Try the log scaling calculator too.

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