Hardwood Flooring
Hardwood Flooring

Surface Finish

Surface finishes for wood flooring provide a protective covering over the boards in a floor. Most homeowners typically associate names such as Minwax or Varathane with these finishes. I am going to go into great depth about this class of finish because the quality can vary considerably, which directly impacts your long term investment.

There are three main classes of wood floor surface finishes: oil based, water based, and conversion varnish. Each system has pros and cons, both of which I am going to describe with full integrity and not a personal bias.

Oil modified polyurethane is very common around the Sacramento region. Here are the pros and cons of this wood floor finish:

Pros

  • Lower material cost.
  • Good durability.
  • Provides a rich color that enhances the look of the floor.

Cons

  • The finish is not chemically catalyzed so the odor lingers around the home for quite a while.
  • Finish is very prone to scuffing and scratching during the prolonged cure phase.
  • Will yellow and become brittle with time and UV damage.
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Conversion Varnish (also known as Swedish finish) is often misconstrued as being a very toxic finish. The truth is that the primary solvent (N-Butyl alcohol) gives the perception that the finish is very toxic. N-butanol is actually a fusel alcohol. Also, a bi-product alcohol from craft brewing. In its aerosolized form, it irritates mucous membranes. I find it very important to go into the chemistry of this finish, because it has such an undeserved reputation for being toxic. I have covered this in greater detail in a blog post here>

So, let’s talk about the positives of this wood floor finish. Conversion varnish has the highest ratio of protective resins (solids) in comparison to any other finish, which is about 50% greater than most water or oil based finish. When this finish is applied to your floor, the coverage rates and mil-thickness do a great job sealing the wood fibers.

Pros

  • Offers exceptional protection and durability because of greater solids content.
  • Has a strong smell initially that dissipates quickly with adequate air exchange.
  • The catalyst in the finish ensures a harder finish with more consistent dry times.
  • Bonds to the wood fibers and all successive finish layers chemically integrate so adhesion loss will not be an issue.

Cons

  • Has a strong initial smell within the first 24-36 hours following application.
  • Will amber (not yellow) with age.
  • Requires exceptional sanding procedures due to optical clarity.
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Waterborne Finish is a very popular finish with many contractors for a variety of reasons. Although this wood floor finish can be durable, there are key elements that you need to know to ensure you get the best investment.

The most critical element to waterborne finish that determines durability is whether is it a chemically catalyzed finish or not. The catalyst adds an additional 25-30% cost to the finish, but adds close to 50% or more in durability. The catalyst added to wood floor finishes crosslinks the polyurethane resins so that you gain additional scratch and scuff resistance. The primary reason that contractors do not often use this finish are: cost and reduced pot life. After 4-24 hours, a catalyzed finish is not generally able to be used, so the waste factor is increased.

Pros

  • The smell from the finish is very minimal and quickly subsides following application.
  • Can be very durable in some situations.
  • Cures quickly, so move-in time is greatly reduced.

Cons

  • Does not age gracefully. Although this finish is touted as “non-yellowing” I liken its aging characteristics to plexiglass in the sun.
  • The resins are optically not very pure, so the floor can look less optically clear. Some contractors favor this look, as it hides sanding errors.
  • Can be prone to white lines syndrome in certain scenarios. Read my blog for more about this.

What you really need to know

All wood floor finishes have varying strengths and what is important is to be open minded to all varieties. What is common in the industry amongst contractors is to learn only one type of finish and then badmouth all other finishes that are available. This underhanded move perpetuates a great deal of myths about wood floor finish. It can leave a homeowner distraught rather than confident in their choice.

Here is my final take on choosing a wood floor finish…Choose an educated contractor with a great attitude to begin your search. I highly discourage reading too thoroughly on sites like Houzz and Pinterest for solid advice, because the the contributors are not actively involved in contracting. If you want a real resource for information online, I greatly suggest to read the forum on Hardwood Floors magazine. The contractors who provide the information are active users of the products and can offer you real long term insight regarding finish durability.

You are always more than welcome to contact me for honest and transparent advice. I am not paid to endorse products and can give you useful insight. Although we live around Auburn, California we are willing to help consumers across the country.