How Many Coats of Polyurethane Should I Put? – An Expert’s Guide
Applying polyurethane is like crafting the perfect recipe – a balance between protection, aesthetics, and durability. And like ingredients in recipes, you have to put just the right amount of Polyurethane coating in your project.
So, just how many coats of Polyurethane should you use? The amount generally differs from appliance to appliance. However, as a rule of thumb, in the case of oil-based Polyurethane finishing you should put 3-4 layers of coating. And for water-based finishing, you can apply 4-5 layers.
Here, we are going to tell you how you can apply Polyurethane coating to your project perfectly. We will also give you a clear idea about just how much coating you should put on different appliances.
Table: How Many Coats of Polyurethane in Different Projects
The table below will give you a basic idea of the number of Polyurethane coatings you need to apply to different projects:
| Project/Surface | Type of Surface | Desired Finish | Oil-Based Polyurethane | Water-Based Polyurethane |
|---|---|---|---|---|
| Indoor or Outdoor Furniture | Varies | Matte to Gloss | 3-4 coats | 3-4 coats |
| Hardwood Floors | High-traffic wood | Satin to Gloss | 3 coats | 5-6 coats |
| Kitchen Cabinets | Wood, Laminate, etc. | Satin to Gloss | 2-3 coats | 3-4 coats |
| Doors | Exterior wood surfaces | Satin to Gloss | 2 coats | 3 coats |
| Stairs | Varies | Matte to Gloss | 4 coats | 5 coats |
How Many Coats of Polyurethane to Put?
One major thing you must consider while giving Polyurethane is what kind you are using. You will find two kinds in the market. Oil-based and water-based polyurethane. Both coatings are suitable for different wood surfaces. I will give you a basic idea about them:
1. Oil Based
Oil-based Polyurethane finish is good for both indoor and outdoor use. They give your wood scratch protection, heat protection, and, to some extent, water protection. Oil-based liquids like petroleum or mineral spirits are used here to dissolve the polyurethane resins.
Manufacturers suggest applying a maximum of three coats of oil-based Polyurethane. However, we recommend you put one more final coating in your work. This will give the surface extra protection.
Accordingly, it is more durable than a water-based finish and lasts for years. However, it takes a bit longer for this oil-based poly to dry. So, you may need to air dry it for about 24 to 30 hours. And once it’s completely dry, your project will have a warm appearance.
The only concerning thing about oil-based Polyurethane is that it has a compound called volatile organic. The chemicals in that compound vaporize in the air while applying this finish. So, it’s not very eco-friendly and leaves a pungent smell for some time. But after a few days, it completely goes away.
2. Water Based
Water-based Polyurethane uses water to dilute Polyurethane resin. It is almost as durable as an oil-based finish, but you need to apply more layers of coating. It has less volatile organic compounds and less odor. So, working with water-based Polyurethane is pretty easy.
Most manufacturers advise that you should put three to four layers of the water-based Polyurethane finish. However, apply one or two extra layers because this finish is thin. And four layers may not always be enough to create a strong barrier.
On the other hand, it takes about 6 to 7 hours to dry. You can finish the whole coating process in a day. Though it is thin in texture, you can use the finish in almost all your projects. You just have to put another layer of coating on appliances you use frequently.
The liquid may seem milky white, but when it dries up, the finish becomes permanent. That’s why people who prefer the color of natural wood use this finish.
Polyurethane Coating on Different Projects
Until now, we have talked about the general coating rule. However, the number of Polyurethane coatings vastly depends on what type of surface you are using it on and how frequently you are going to use it. Here is the guideline for this:
Indoor and Outdoor Furniture
For most indoor and outdoor furniture 2-3 coats of any Polyurethane would do. You just have to make sure that the finishing you are buying for the outdoor furniture has Zinc Oxide-based UV protection. Otherwise, sun exposure can make your furniture turn yellow.
Kitchen Cabinets and Table
Kitchen cabinets are a frequently used appliance. So, while applying the coating, you should put an extra layer here. Especially those close to your stove will need a nice protective barrier.
That’s why we recommend that you put either two to three coats of Oil-based or three to four coats of water-based Polyurethane on it.
For tables, you will need to apply two to three layers of either of the Polyurethane coating. The finishing makes the surface of your table smooth and glossy.
Doors
Interior or main doors don’t need that much protection since we don’t usually touch their whole surface. In this case, three water-based and two oil-based Polyurethane coating layers should be adequate. For the main door, you should use a coating with UV protection.
Hardwood Floor
The floor is something you walk on frequently. Without a sturdy barrier there, it might become dented. So, it’s no surprise that you will have to apply more Polyurethane finish on hardwood floors.
We recommend you apply at least 3 layers of oil-based and 5 to 6 layers of water-based Polyurethane coating.
Stairs
On stairs, we often thump, jump, and run. The everyday striding means that it needs all the protection it can get. This means you need to apply four layers of oil-based coating and at least five layers of water-based coating.
FAQ
There can be a lot of questions going through your mind right now. You can find your answer here:
Q: How long does any Polyurethane finish last?
Water-based Polyurethane finish can last about three to six years. The Oil-based one should last you more than that. But it highly depends on your lifestyle and how frequently you are using your wooden material and how you are using it.
Q: Is Polyurethane really waterproof?
To some extent it is waterproof. But not completely. We say this because poly absorbs water. If you accidentally pour water on it once in a while then the coating will not be damaged. However, if it happens often, water will damage your Polyurethane coating.
Q: Is Polyurethane Strong?
Polyurethane is really strong. In fact, it is stronger than rubber. The tear resistance level reaches up to 100 to 1,000 lbs./linear inch. Which means the coating is wear and tear protected.
Conclusion
So, now you know how many coats of Polyurethane you should put in any appliance. For oil and water-based, the amount is generally different. At the back of the Polyurethane coating’s tin, you will find the manufacturer’s recommendation.
But remember, this is vastly generic. They don’t consider factors like the appliance type, how often you will use it, and your method of usage. That’s why you won’t have to worry about anything if you follow our recommendations.
