The more you learn about polyurethane, the more you find yourself asking – why can’t it be more like paint?
Or at least that’s how I felt when I first started. Everything about it seemed so complicated. Now, applying polyurethane is second nature to me, and I’m here to make it easier for you too.
In this article, you will learn:
- How many coats of polyurethane you should apply for different jobs
- Why you often need more than one coat
- If and how you should use one coat of polyurethane
- How long to wait between coats
Now, let’s get into the action.
How Many Coats of Polyurethane Should I Apply?
For best results, apply at least two coats of polyurethane. When working on floors, tables, chairs, and furniture that will be used often, apply at least three coats. If you are using water-based polyurethane, you can apply up to four or five coats on floors and sheds.
Is One Coat of Polyurethane Enough?
Like I mentioned earlier, applying polyurethane can be a tricky affair. Different problems tend to arise after the first coat, such as brush marks (or lint when using a roller), dust nibs, and bubbles. As much as the flattening agents in polyurethane are meant to level out bubbles and brush marks, it rarely works on the first coat.
If these problems occur, you need to sand out the imperfections and then apply at least one more coat. After you apply the second coat, you will notice that the surface is smoother and has fewer imperfections.
If there are still bubbles or the wood doesn’t look glossy enough, then you need to learn how to apply polyurethane without bubbles.
Applying a third (and usually final) coat of polyurethane will do the trick. This will yield an excellent finish and will protect your wood from the elements for years.
Are 4 Coats of Polyurethane too Much?
In most circumstances, you only need three coats of oil-based polyurethane. You can use four or five coats of water-based polyurethane for hardwood floors, especially those that will see a lot of traffic or a lot of moisture. For all other projects, manufacturers usually recommend three coats, even for water-based applications.
When you are reviving old furniture that already has a finish on it, you won’t need more than two coats. However, if you sanded the old piece down to the stain, then you would need at least three coats of water-based polyurethane.
Whatever you are working on, you won’t go wrong with applying four coats of polyurethane. The only downside is that the project will take longer to complete, and it will cost more.
How Many Coats of Polyurethane on Wood countertops?
You need at least two coats of polyurethane on wood countertops. If this is a surface that is going to be used a lot, then apply a third coat. If you are using water-based polyurethane and it raises the grain of the wood, you may need more than three coats.
How Many Coats of Polyurethane on Kitchen Table?
You should use at least three coats of polyurethane on a kitchen table. Just like floors, kitchen tables will go through a lot of abuse – liquid spillage, cutlery constantly scratching and pots banging -, so it needs more protection. With three coats, you won’t need to refinish the table anytime soon.
How Many Coats of Water-based Polyurethane on Hardwood Floors?
Most manufacturers recommend three to four coats of water-based polyurethane on hardwood floors. You’ll only need more coats if you’re using a water-based finish not made for floors, or you overdiluted the poly. However, if you haven’t gotten a smooth finish by the fourth application, sand it over and apply another coat. Keep going until you get the desired result.
How Many Coats of Polyurethane on Stairs?
Stairs are high-traffic areas, so you should apply at least three coats of polyurethane. The same is true for water-based and oil-based poly alike. If you applied a sealer coat, you may only need two coats of water-based polyurethane., but as always, keep going until you get a smooth finish.
Is One-Coat Polyurethane Good?
Due to the long drying time of polyurethane, a few manufacturers have been trying to come up with quicker and easier solutions. An increasingly popular alternative is a product called one coat polyurethane.
Just as the name implies, you only need one coat to get an excellent-looking finish on any wooden object. Or at least, that is what they say. Another name it goes by is triple-thick polyurethane. These products are usually water-based.
The one coat or triple thick poly is noticeably thicker than oil-based polyurethane. As a result, it is more difficult to apply, and I am yet to meet any professional who would rather use this than go through the hassle of applying other coats three times.
The main reason is it is near impossible to get a smooth finish with just one application of one coat. As it does not level out as it dries, you will see a lot of brush marks on the one coat. You, therefore, need to sand it and apply a second coat before it becomes smooth.
Ironically, you might still need a third coat of the so-called one-coat poly. Not to mention what happens if you don’t sand between coats of polyurethane. For a product that costs more, it really isn’t worth the trouble.
The one instance where I recommend the one coat is when you are building something that does not need to be aesthetically pleasing. Shelves in your garage, for example, or children’s toys built for destruction.
One coat is quite durable and can withstand more abuse than regular poly, making it ideal for these types of construction.
Can I thin Polyurethane?
Yes, you can thin polyurethane. As a matter of fact, thinning polyurethane makes it easier to use. This is because the poly levels better, so brush marks disappear better.
You may also choose not to thin polyurethane, especially water-based polyurethane. Some people say thinning helps the poly bond better, but that isn’t true. The most significant benefit is that it dries quicker, thus reducing the time between sanding and reapplication.
How Should I Thin the Different Types of Polyurethane?
The best product for thinning oil-based polyurethane is mineral spirits, while water should be used for water-based polyurethane. However, as mentioned earlier, you can do without thinning water-based finishes.
Another alternative for thinning oil-based polyurethane is paint thinner. Paint thinner is technically mineral spirit, but it has more impurities, so it should only be used if you can’t find mineral spirits.
Naptha is another mineral spirit you can use, but it is highly flammable.
How Long Should I Wait Between Coats of Polyurethane?
You can apply the next coat of water-based polyurethane, usually within 2-6 hours. Despite the instructions by some manufacturers, you should wait for at least 24 hours when using oil-based polyurethane.
However, you can apply another coat of fast-drying oil-based polyurethane within 4 to 6 hours. One factor that determines the wait time is if and how you have thinned the product. Thinning significantly reduces the wait time, but try not to overdo it, or you’ll end up needing more coats.
How Many Coats of Polyurethane For Your Next Project?
No matter how tricky it might seem to use polyurethane, its advantages outweigh any disadvantages. It may take some getting used to, but it is a skill worth mastering for personal and professional reasons.
Now that you know how many coats of polyurethane you need on your project, it’s time to decide which type you are going to use and which manufacturer.
We have a bunch of articles that will help you choose. I recommend our review of Varathane vs. Minwax or our comparison between oil-based and water-based polyurethane. Whatever you choose, it’ll be a great read!