Q: Oil or varnish on wood floors as finish; pros and cons, which is the better choice of the two?!
A: Your question is very pertinent at the moment, if by “oil” you mean “penetrating oil finishes”. I have just finished the first half of a project where the home owner did not want polyurethane/varnish on her floors. She didn’t like the look. I have read very good reviews regarding a tung oil based product called Waterlox which I have used. There are certain similarities between the products and there are differences. Varnish, polyurethanes, combine different oils and resins in the product, even as penetrating oils do. As the name implies, penetrating oils purpose is to soak and penetrate deeper beyond the wood surface, hardening the fibres beneath. You do get penetration with oil borne poly with the first coat in particular, and then you start to build film layers after that.
One floor finisher told me that he had a roof leak onto a second coat of Waterlox. When he entered the next morning, a large puddle was on the floor. No damage to the floor! I would call that exceptional resistance to moisture. Polyurethane also has good resistance to water. I consider both products to be near equals in the durability department. Polyurethane may be slightly harder than Waterlox, for example. However, everything will get banged up eventually. Touching up a tung oil finish such as this is easy. Wipe some on the spot. Let dry. Poly is more difficult to deal with. Every coat must be sanded to gain adhesion with another coat. It is very difficult to do a spot fix on poly without it showing, but a floor well finished with several coats of oil borne varnish/polyurethane will give many years of service without a re coat, and minimal fuss over maintenance.
You might have to do a maintenance touch up on tung oil occasionally, but it is a snap to do. Penetrating oils have a softer, more natural hand rubbed look.
For longer term wear without having to do a maintenance coat, poly is probably slightly better. but when you do another coat, the floor has to be lightly sanded to gain adhesion.
Tung oil/Waterlox offers near comparable durability and excellent water resistance along with a different look that many people appreciate. Touch up may be more frequent, but it is easy to do. Any commercial jobs I have done in the past always used a penetrating oil rather than polyurethane. It was easier to maintain in that environment. They didn’t have to shut down the place for several days to re coat the floor.