This is probably the question I get the most often in my profession. What type of finish is better. My answer usually isn't what people expect, because it isn't a simple answer. There are many differences and we will explore them in this posting. Ultimately, your circumstances will determine which finish is better for you.
Durability - this is probably at the heart of the question "which one is better." If you were to ask 100 flooring contractors this question, you would probably have 50 of them say that oil poly is better. 49 would say that the water-base is better. And me, always the outlier and the nonconformist, would say that they are too similar to differentiate with respect to durability. I'm sure that their are plenty of old schoolers and chemists that could make a solid arguement for one or the other, but what they can't do is ensure that everybody applying the finishes are using good brands, not thinning them down, and making sure that they are applied properly, both in terms of number of coats AND thickness of each coat.
What I have found over 10 years in the industry is that if each product is applied properly using quality products, the difference in durability is indiscernable.
So, why do I think that 99 contractors out of 100 will swear on one finish or the other? I suspect that what they are telling you is what type of finish they like working with the best.
That said, I would not be discouraged if you meet with several flooring contractors and they don't agree on which type of finish is better. If you feel like you have met someone you can trust and they come well recommended, you are best to allow them to work with the finish they like to work with. They will do a better job with that type of finish.
In my practice, I have crews that specialize in water-based finish and crews that specialize in oil-based finish. Therefore my clients decision to use a particular type finish will not be related to what I like better, rather it will be a decision that we come to based on the following factors.
Price - This one is simple. Water-based finish costs more than oil-based finish. Usually by a square footage factor of 50 cents to dollar more.
Convenience - Dry times and smells - water based finishes dry in 2-3 hours per coat and have very little odor (smells like a very mild cleaning product). Each coat of oil-based finish takes 10-20 hours to dry and has very high levels of VOC. Typically, you should plan to be out of the house for 2-3 days if working with oil-based poly.
Look - Oil poly will typically give the floor a little color and richness, while the water-based products tend to be clear. If you will be staining the floor, this is mostly a non-factor as the stain will be determining the color and not the finish.
Over time, the oil poly will darken and amber while water-based finish will hold it's color better. This can be a significant factor in 5 years and may or may not be a good look for your house.
Feel - oil poly conditions the wood better than water-based products and therefore you can expect that the oil poly floor will feel smoother upon completion. This difference is especially noticeable if you hire someone who strongly prefers working with oil and you hire them to do water anyways. If you hire someone who prefers water, they should know the "tricks of the trade" to make the floor smooth. Further, both floors will smooth out (the grain will settle down) over the first couple of weeks as the spirits or water fully evaporate. And finally, as you live on your floors, your foot traffic will further polish the floor.
All that said, if your floor feels like sand paper, your contractor should lightly sand and put down another coat of finish (assuming the floor looks good and is just rough).
To conclude, I hope that I have given you enough to think about to make a solid decision. For most of my clients, we usually make the decision around color and the convenience factor.
As always, feel free to email me firstname.lastname@example.org with more questions on this topic or ANY topic related to hardwood, laminate and tile flooring.
Until next time,