Low odor polyurethanes have lower VOCs.
And lower VOCs are healthier for you and healthier for the planet. But it is more difficult to engineeer low- or no-VOC protection.
Hardwood floor finishes need to incorporate really hard, wear-resistant resins and solids in order to protect your floors. But these resins need to be invisible because we want to see the wood through all that protection; otherwise you may as well just use paint.
This is a pretty big challenge already.
But the next huge problem is you have to get these solids to dissolve into liquid form first, so they can actually be applied evenly to the wood.
Getting these protective resins to remain in liquid form in the can, but become solid on your floor requires potent chemical solvents. And the best solvents have historically come from distillations of petroleum.
Most of these solvents are dependent on a class of chemicals known as Volatile Organic Compounds (VOCs). These chemicals evaporate and spread easily through the environment, but also degrade very slowly. But while these high-VOC solvents do their job well, they are increasingly correlated to respiratory harm, cancer, and environmental damage.
Most people think that the damage from these VOCs is minor and only happening when the finish is fresh and you can actually smell the solvent.
Do not underestimate the severity of this short term degradation of indoor air quality. The headaches, dizziness, nausea, and nosebleeds experienced by flooring professionals and by home occupants during floor refinishing are major.
“Exposure to very high levels of VOCs may cause damage to the liver, kidney, or central nervous system (brain and spinal cord). High levels may also cause vision and memory problems.” [1]
Health effects of VOCs (Volatile Organic Compounds)
Health effects may include:
- Eye, nose and throat irritation
- Headaches, loss of coordination and nausea
- Damage to liver, kidney and central nervous system
- Some organics can cause cancer in animals, some are suspected or known to cause cancer in humans.
Key signs or symptoms associated with exposure to VOCs include:
- conjunctival irritation
- nose and throat discomfort
- headache
- allergic skin reaction
- dyspnea
- declines in serum cholinesterase levels
- nausea
- emesis
- epistaxis
- fatigue
- dizziness
But there’s more.
Eventually these solvents evaporate out of your finish, but even though the heavy concentration of VOCs in your house has eased, the long-lived nature of these chemicals means that they continue to cause damage out in the environment.
Some are considered “greenhouse gases, which are able to absorb radiated energy from Earth, their concentrations increase in the atmosphere [and] have been correlated with the global warming.
Furthermore, VOCs from wastewaters decrease the possibility of water reuse, such as in irrigation, thereby placing a higher demand on the limited existing primary water resources.” (Niculescu, 2021 Dec; 18)
Here at Pete’s, we know firsthand the discomfort and damage that these chemicals cause and want to be part of the groundswell of demand for higher-performing, low- or no-VOC floor protection.
But there’s the rub: most customers insist that safer products like low odor polyurethanes or european-style penetrating oils are not protective enough.
We are here to tell you that is hogwash.
Yes, it is much more challenging, from a chemical engineering standpoint, to create finishes that protect without relying on crude-oil derived solvents.
But so much progress has been made, just in the 20-odd years we have been in business that we can now offer you multiple, high-quality, low-toxicity finishes.
There are two ways chemists are solving this problem:
- Replacing petroleum-derived solids, binders, and solvents with lower-VOC alternatives in traditional, polyurethane-style film finishes.
- Working with botanically derived oils like linseed, soybean, or tung to create finishes that cure from liquid to solid using oxygen, and eliminating the need for solvents and plastics altogether.
Both of these are valid pathways to the same goal of having a transparent finish that allows you to live on the floor, enjoy its beauty, but keep it constantly protected.
Both methods have pros and cons you should be aware of. No floor finish, not even those super-toxic OG formaldehyde moisture-cured varnishes from the 70s can give you everything.
[1] Ohio Department of Health, Bureau of Environmental Health and Radiation Protection Fact Sheet 1/8/2021
Option 1: Building a better polyurethane
Okay people, stop hating on polyurethane.
This clear, tough protection allowed hardwood floors to re-emerge from the dark ages.
From the 1850s through the late 1950s it was extremely labor-intensive to keep hardwood floors looking good. The varnishes, shellacs and waxes were so mediocre and yet so time-consuming to maintain that generations of homeowners rejected wood floors entirely and covered them up with carpet.
Do you ever wonder why so many people are “discovering” hardwood under carpeted or sheet-vinyl floors?
Because people literally hated taking care of hardwood so much that they glued new floors on top. But as soon as they came up with a coating that was durable and easy to apply, people starting ripping that carpet up.
Early versions of these coatings, chemically referred to as “oil-modified polyurethanes” are still manufactured today. They are falling out of favor because they are amber-tinted and give that characteristic “orange” look to floors that is currently so scorned.
But some customers still insist on using them because they assume that those paint-thinner based finishes were superior. They may have been superior to the waxes and shellacs that came before them, but they are no longer king of the hill.
But the problem is, these old school polyurethane rely on large quantities of mineral spirits, a cheap, readily available petroleum-derived solvent. These products have VOCs in the 500-600 g/L range. So, in the 1980s, they started researching ways to build polyurethane that did not rely on mineral spirits.
The first patent for a waterborne low odor polyurethane was granted to the BonaKemi company out of Sweden. Early versions of the product were certainly less stinky, but also very challenging to apply, and not even as protective as the early solvent-based polyurethanes. But they have improved quickly. Today’s epoxy style two-component waterborne floor finishes are more protective than any historic floor finish.
Within this class of finish, Pete’s still carries the Bona line, but has added a newer line from Germany called Pallmann. Both have significantly lower VOC levels than mineral-spirits based polyurethane, somewhere between 110-250 g/L.
But, even though these products replaced most of the mineral spirits with water, they still relied on small amounts of particularly toxic solvents like Xylene, Aziridine, and Toluene to get the solids to cross-link.
Isocyanates were used in the hardeners to get these finishes to perform better. They needed to use various ammoniated chemicals to control the tendency of the water to leave unpopped bubbles in the finished surface. And they needed to add biocides to the mixture to keep it from molding!
So even water-based finishes had the same dangers associated with paint thinner, plus other mutagenic and irritant risks.
So, the next step was keeping the water as the main solvent base, but find alternatives to these other, smaller quantity additives. This has been a slow process.
But Vermont Natural Coatings makes a line of floor protection that has reduced VOC levels to under 60g/L by using whey, a byproduct of the dairy industry, to replace both solids and solvents in their finishes.
Finally! Because we have been able to buy zero-VOC paint for a decade, it’s been hard to explain to people why we can’t have that for floors.
So, if you are used to the idea of having a clear, low-gloss but tough protection over your wood that you expect to last 10-20 years before you need to apply a fresh coat, this is the product for you.
Yes, it is a multi-layer “plastic” finish, but that plastic comes in satin or matte sheens so your floor won’t look like a basketball court.
But this still has a small amount of volatile organic compounds. If you need a ZERO-VOC formulation or want something with no plastics whatsoever, you want to look as this option:
Option 2: European-Style Penetrating Finishes: Hardwax Oils or Hardened Oils
In Europe, they have been using penetrating finishes as an alternative to varnishes and polyurethanes for years.
This product type has been slower to reach our shores.
But here at Pete’s, we were getting sick (literally) and tired of the solvents and stink of conventional hardwood flooring finishes. And we really needed a product that we could actually recommend to those who were pregnant or chemically sensitive.
We started looking for options.
So, back in 2008, with much hesitation and skepticism, Pete’s began to explore options in the vast field of hardened oil and hardwax oil finishes.
We were skeptical at first, not just because these products were new to us, but because these finishes promise protection using only one layer of product on the wood. This was unheard of.
Current floor finishing wisdom says that the best way to protect wood is to encase it in multiple layers of tough plastic – you just finished reading our explanation of why polyurethane is so adored!
But hardened oils work differently: they are driven into the wood and harden and strengthen the wood itself; there is not really a film or layer that builds up on top of your floor.
The very notion of whisper-thin layer of oil being able to protect wood not only from spills, but from the grinding onslaught of a Minnesota winter was, frankly, outlandish.
The first product we tested was Rubio Monocoat.
But even the Monocoat name made us worried: one coat?! How will one coat of anything, let alone one without solids, protect a floor? Our expectations were low.
So, we tested these products ruthlessly. We spilled red wine. We left wet metal on them overnight. We poured coffee on them. We burned them with ammonia. We applied them under rolling chairs, at exterior doorways, and all the places where customers stand with their salty, wet boots. Maintenance guidelines? We ignored them.
These products should have failed miserably. But they didn’t.
And we now carry two different brands of penetrating finish – Rubio Monocoat and Pallmann Magic Oil – and they now make up over half of all the finish we sell.
Penetrating finishes are not categorically better than polyurethane, but they do solve some of the inherent problems of that type of finish.
Here’s what we’ve learned about why these hardened oils will hold their own against polyurethane and are here to stay:
EXTREMELY LOW ODOR!
They can be coated year round, even when you can’t throw the windows wide open
Hardwax oils are just oils. Rubio Monocoat is essentially linseed oil and Pallmann Magic Oil is soybean oil. The oils are altered for speed of cure, and carnauba and beeswax are added to give water resistance.
But there are no other solids or solvents added so these products are far safer for both respiratory and neural systems, especially during application. Yes, even for pregnant people, babies, and other beings with tiny lungs – like gerbils and Chihuahuas.
Even in winter, hardwax oils are so inoffensive that you don’t have to move out of your home during coating. Hardwax oils are food safe for countertops; some brands are even cut-safe for cutting boards.
They make the wood look like, well, wood.
One of the objections to polyurethanes, even low-VOC versions, is that you can “see” the protection. If you want your floor to look like it has nothing on it, as close to natural as it was when it was a tree, then a penetrating oil finish is a great choice.
Especially in the lighter colors, it can give the appearance of complete, ahem, nudity. Even the most matte polyurethane finishes can look like Formica. If you bought your wood floor because you wanted to see and feel the wood itself, penetrating finishes help achieve that.
The other advantage of this minimal approach is that floors treated with penetrating oils look even better over time. Well-maintained hardwax oils develop a patina from maintenance and use that feels timeless and unobtrusive.
Hardwax oils are extraordinarily tough for their thickness.
These finishes may only be fraction of the thickness of a conventional polyurethane finish, but as long you refresh your hardwax oil just once a year, it will deliver the performance of a multi-coat poly or varnish. This doesn’t meant sanding your floor every year – just reapplying a layer of either a maintenance product or the oil itself.
The shop floor at Pete’s is living proof that if you just booster coat a hardened oil on the regular, it will withstand wear, water, salt, and sundry solvents.
It can handle regular washing – water will bead and evaporate. It is not better than a typical polyurethane floor, but certainly no worse.
That said, you still need to be aware of pet accidents and pet drool – sometimes these liquids are corrosive and affect many finishes, not just hardwax oils. So you can’t just let your pets pee on a hardwood floor.
Same for foods like saffron, turmeric, and beets, which will stain just about any surface. And wear spots will appear fastest where you have the most friction: exterior doors, in front of the fridge, and the dog’s water dish.
Yes, the hardened oil involves more frequent maintenance, but it is a small price to pay for a VOC-free and solvent free experience that ages gracefully.
Easier to spot-fix, up to a point.
One of the selling points of a thinner, non-layer-forming finish is that you should be able to lightly sand a worn or discolored area and just reapply a bit of the original oil. This is really hard to do with polyurethane – you can always see your repair zone.
Because hardened oils are designed to bond just to wood, and not to wood already coated with the oil, you get “edgeless” repairs. And we have found this to be reliably true for the plainest colors like Rubio Pure or Pallmann Magic Oil Neutral.
But if you have used colored oil, or have used one of the colored pre-treatments under your topcoat of oil, your floor will be harder to spot-fix invisibly. Replicating the wood texture that allowed original color absorption and intensity can be tricky, so think carefully about making crazy colors if you are relying on an easy-to-repair surface.
Are we saying that penetrating-style finishes are BETTER than all other finishes?
Nope. We are saying that they are a legitimate alternative to more traditional finishes, as long as you heed their maintenance guidelines.
You can dig even deeper in to the three brands we sell below.
Do you need advice for your specific hardwood floor problem?
Get a one-on-one phone consultation with a hardwood flooring expert. For a small fee of $25, we can provide the wisdom and knowledge that you need to complete your hardwood flooring project. When you don’t know what you need to do next, that’s when it’s time to call Pete’s Hardwood Floors Help Hotline.
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