Testing Hardwood Floor Finishes in an Old House (Part 2)

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For part 1 of this series and backstory, click Testing Hardwood Floor Finishes.

The Commonly Accepted Hardwood Floor Finish Tests and Paired Solvents

Listed in order of aggressiveness of paired solvent.

• Wax – “The Water Test” identifies flooring that has not been sealed, or at least floors that have wax on them. Water on an unsound floor will temporarily pale the floor finish.

 – Mineral Spirits – Will remove Wax. Wax sometimes need to be removed before further tests or refinishing.

• Polyurethane – Oil-based polyurethane (as often found in old houses) is thinned with Mineral Spirits. While water-borne polyurethane can be thinned for application with water, water will not remove polyurethane.
• Shellac – Denatured Alcohol thins Shellac.
• Varnish – Acetone thins and will remove Varnish.
• Lacquer – Lacquer Thinner thins and with extended soaking, will remove Lacquer.

Testing Hardwood Floor Finishes In a Closet :: Testing the Tests

So I found myself in the closet.  I knew pretty well that I did not have varnish on my floors.  I remember that coating from my grandfather’s boat, on and around his basement bar, and probably on a few other things that survived from his day. Varnish is so shiny, you could see your reflection in it — or at least that’s how I knew it.

And the species of wood?  In a house that contains everything from cherry to cypress (I think; and fairly uncommon in my region) to things that smell of fir . . . I can make a pretty good guess. This bit of information is important too when we discuss floor finishes.

Identifying the Existing Wood Floor Species Benefits Refinishing

For now, we will call it an oak floor with a walnut inlay (though maybe something slightly different can be found in the closets). This configuration was very popular throughout the houses of my region. I do not have a great guess on when it was installed.  But how it was butted to certain wall surfaces, and what was in those walls makes me think this floor was installed in or around the 1960s.

This floor is installed on a sleeper system, and is definitely not similar to some of the southern yellow pine floors I have seen. Oak, but it is soft, and has many dents, dings and scratches to prove it.

The second floor’s floor has some wax on it, but applied only over a more original finish.  I believe this because water when dripped on it will pale the surface to a sickly off-white. This condition does quickly subside – and a goldish brown does ultimately return.

The finish is generally consistent insofar as it is inconsistent throughout the house. Since there are no signs that these floors had ever been covered, the assumption has always been — stained (maybe), with coats of well-worn and time-darkened clear coat over it.

Video :: Testing Hardwood Floor Finishes in a Closet

The video below will show you what I know.  It will not show you that I first used water to test for the “soundness” of the floor.  And while I am pretty certain that some locations have a thin layer of wax on them – I do also believe that these floors, and definitely in this closet here, had some sort of solvent-based sealer applied to them.

I tested for shellac, varnish and lacquer.  These tests, advised by multiple resources and documented in the preceding post, left me, well . . . a little perplexed.  All the literature made it seem just that slam dunk  The assumption – acetone thinning varnish and not any other finish, etc.  But who knew. . . .

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What I found was that all three solvents selected – lacquer thinner, denatured alcohol and acetone thinned the floor’s finish with little or no resistance.  In other words, these tests did not really reveal anything in particular.  Each of these three solvents can aggressively clean and/or even strip (down to the bare wood) this (my) floor finish. Lacquer Thinner strips water-based polyurethane.

Get Advice on your Floor Finishes from a Local Flooring Pro

So . . . then somewhat befuddled – I first rang up second generation floor man, Daniel Manger at Danzco Floors. On explaining to him all of what I had found, he said – “Polyurethane really didn’t begin to replace other finishes until the ’70s.  But still, I would expect your floor to have a coat of urethane on it.”

And I told him more, he said – “Sounds to me like you might be looking at lacquer.”

Only after research, I learned that lacquer can be colored.  (I had always associated lacquer with the spray on clear coat for furniture and/or cabinets.)

I finished by telling Daniel that I did notice more of a tackiness when using the acetone, less with the denatured alcohol – and instead, just straight easy removal with the lacquer thinner.  “Lacquer” — he said, and then he proceeded to call out – Fabulon.

Later I learned that Fabulon is still manufactured today, but more commonly now is water-borne. It was installed widely in the 50s and 60s, and in that original form was, guess what, lacquer-based.

(In the spots seen in the upper frame of the video — I actually poured out a small amount of the lacquer thinner (and well acetone in another location), wiped it on and later finished with mineral spirits.  Both of these tests pretty well removed the finish.)

Turning toward Refinishing

So, here I am — a partially stripped floor, still not completely confident that I know what the finish is.  With the closet almost finished, I turn my thoughts to how I might refinish this small floor.

Dean Morgan, the resident stain matching expert at Budeke’s Paints, says, “I don’t know what you have there, but you are going to have to test new finishes using a combination of stains and polyurethane.” And as if I knew it before he said it, “It is going to take a lot of trial and error.”