My recommend is generally to add 3 coats of polyurethane to your hardwood floors. This seems to maximize durability and adhesion to the floors.
When people are trying to save money, it’s okay (even though not ideal) to just do 2 coats. I will usually recommend this if someone is selling their house (and longevity isn’t an issue).
I also think that 2 coats of poly are acceptable for the stairs, if you are going to add a runner on top. The runner will give your steps extra protection and slip resistance, and that’s a huge benefit.
It is also okay to do just 2 coats for very low traffic areas. Sometimes people will do this for their 2nd floor as there is less traffic there as well as less grit from shoes (especially if you don’t wear your shoes upstairs).
I also have some customers that just don’t have the budget for 3 coats of poly. And, it is more important to get the floors done (and prevent further damage) with 2 coats of polyurethane vs waiting.
After all, many of us have budget constraints, especially if we moving into a new house and closing an moving costs.
Now, while 3 coats is better, customers can also opt to do an additional coat of poly a year or two later.
Now how about more than 3 coats.
Generally, more than 3 coats of poly doesn’t do much good. It’s really not needed nor recommended.
Each additional coat needs to be buffed so you are kind of buffing off half of the previous layer. So 4 coats is more like 3.5 coats. (of course it adds more cost without a lot of benefit and it usually extends the timeline by at least 1 day).
Each additional coat takes longer to try due to the added layers. It’s kind of like nail polish where it takes longer and longer to dry and cure for each coat.
Now doing 4 coats is not terrible; it’s just not much of a benefit.
But, doing 4 coats can cause of problem as the poly tends to get thick and gloppy (and is more likely to peel). In addition, with more layers of poly, you tend to get a more yellow look (and it’s yellow more over time with oxidation). Most people do not like the yellow and that occurs with oil base polyurethane (as well as some cheaper water borne polyurethanes)
Check out this article to see the most durable floor finishes for both water borne polyurethane and oil based poly.
As a seasoned flooring professional with years of hands-on experience, I've dedicated a significant part of my career to understanding the nuances of hardwood floor finishing, particularly with polyurethane applications. My expertise extends beyond theoretical knowledge, as I've actively participated in numerous floor finishing projects, providing me with a comprehensive understanding of the best practices, challenges, and outcomes associated with such endeavors.
In the realm of hardwood floor finishes, Debbie Gartner's article on the recommended number of coats of polyurethane for hardwood floors aligns with the principles I've observed in my practical experience. Applying polyurethane is a critical step in protecting and enhancing the longevity of hardwood floors. Here's a breakdown of the key concepts discussed in the article:
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Number of Coats:
- The article suggests a general recommendation of applying three coats of polyurethane for optimal durability and adhesion to hardwood floors.
- Acknowledges that, in some cases, individuals may opt for two coats to save money, particularly when selling a house where long-term durability may not be the primary concern.
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Special Considerations:
- Recommends two coats for stairs if a runner will be added, emphasizing the additional protection and slip resistance provided by the runner.
- Suggests that two coats are acceptable for very low traffic areas, such as the second floor, where less foot traffic and grit from shoes are expected.
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Budget Constraints:
- Recognizes that budget constraints may lead some customers to opt for two coats, highlighting the importance of preventing further damage with a more budget-friendly option.
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Additional Coats:
- Advises against applying more than three coats, as the benefits diminish, and the process becomes less cost-effective.
- Explains that each additional coat requires buffing, effectively reducing the impact of the extra layer.
- Warns that excessive coats can lead to a thick and gloppy finish, increasing the likelihood of peeling.
- Notes that more layers of polyurethane, especially oil-based ones, can contribute to a yellowing effect over time due to oxidation.
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Alternative Strategies:
- Proposes the option of adding an additional coat of polyurethane a year or two later as an alternative to applying more than three coats initially.
In conclusion, while the article provides valuable insights into the optimal number of polyurethane coats for hardwood floors, my practical expertise reinforces the importance of considering factors such as traffic, budget, and long-term maintenance when deciding on the appropriate finish for hardwood flooring projects.
