Linseed, tung, refined hemp, soy, and poppy seed oil, are all-natural oils that on their own can be used to seal and protect hardwood floors (both solid wood and unfinished engineered wood). They are usually called “penetrating oils” on sales pages but the technical term for these oils is “drying oils”.
Drying oils polymerize in the presence of oxygen, they provide a long-lasting finish that does not turn rancid, and that’s what you need to penetrate, harden, and preserve wood.
Non-drying oils won’t polymerize and form a durable coating (source). I wouldn’t recommend using olive oil, coconut oil, or other non-drying oils because they don’t harden and some can go rancid on wood.
Linseed and/or tung are often labeled as “teak oil” or “Danish oil”, though this is a non-specific term that can mean either it’s pure or mixed with additives and solvents.
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Are they 0-VOC?
Some oil finishes are totally natural, solvent-free, and non-toxic. Others are mixed with driers and solvents and can be higher in volatile organic compounds (VOCs) and odor.
Even with a pure oil like linseed or tung oil, during oxidation (curing), aldehydes and hydrocarbons are produced. Peroxides, alcohols, ketones, and acids may also occur during oxidation (Source). In low concentrations, like those that come off linseed and tung oil, these compounds are not considered toxic. However, those who are chemically sensitive can certainly have trouble with these natural VOCs and should test all options first.
The finish of natural oils is a matte look, though waxes can add a subtle satin sheen. This gives a finish that looks like century-old wood, a rustic look, or a modern matte look.
Many of the oils come in a good range of stain colors as well. With some, you can apply a water-based or alcohol-based stain first before the oil.
The maintenance on natural oil floors is fairly easy as you don’t need to sand it down – you can either spot repair or add a coat over what you have.
You need to reapply a maintenance coat of oil every year to every five years depending mostly on the wear but also check with each brand for what they recommend.
I’m going to review pure oils, oil mixes, and oils mixed with driers and/or solvents.
PART 1: My Top Three Choices
1. Rubio Monocoat
This option is the easiest to apply as it’s just one coat. It also comes in the most color options and if you only use Part A it’s the only solvent-free option.
Rubio Monocoat Oil Plus 2C is their interior floor finish. It’s a linseed-based finish (natural and modified) with a wax component (natural and modified as well).
Compared to other natural oil finishes, this one is relatively easy to apply. You apply it with just one coat, and you can touch it up easily with spot treatment without sanding. It can be applied to all wood types (and they show you what the stains look like on white oak, red oak, maple, pine, hickory, walnut, and cedar).
They claim zero-VOCs but you should test any linseed product before using it if you’re sensitive to chemicals or odors. This is lower odor than regular linseed or tung oil. It smells like honey or lemony incense.
I tested this finish and was very happy with it, it’s my top choice on the list
Color and Finish
It is a matte finish that comes in over 50 colors, including bright colors, greys, and whites along with the usual brown wood stain colors. Even the Fumed product (to grey out the wood) is 0-VOC and ammonia-free.
Chemical Additives in Rubio Monocoat
The accelerator which is a Part B drying agent lists hexamethylene diisocyanate as an ingredient (0.5%), but not all ingredients are listed. Part A (without the drier) takes a long time to dry, and this is likely a purer linseed.
It does contain non-aromatic hydrocarbons which they claim are not solvents. Non-aromatic hydrocarbons that can be used with linseed oil but are not a solvent include alkanes such as pentane, hexane, and heptane, and cycloalkanes such as cyclohexane, as well as the less common alkynes and alkenes.
I could not get the company to claim no metallic driers, though it does say it’s free of the following heavy metal drying agents. But it is Toy Safe EN-17 which means it doesn’t contain any significant levels of aluminum, antimony, arsenic, barium, boron, cadmium, chromium (III and VI), cobalt, copper, lead, manganese, mercury, nickel, selenium, strontium, tin, organic tin, and zinc. And they add that it’s also free of beryllium.
Other metallic driers for oil-based finishes (that they don’t say they are free of) include: calcium, iron, vanadium, and zirconium.
Cure Time of Rubio Monocoat
How to Apply Rubio Monocoat
Apply one coat using a buffer, trowel, or squeegee. Remove excess oil with a cloth. Perform a final wipe with a clean terry cloth under a buffer.
They have a Maintenance oil that can be reapplied when the wood looks dull, which can help keep it up. You reapply Oil Plus 2C when the color fades or is worn down.
This is a single-coat finish, making it much easier to apply than most of the other options on this list. It’s also the only one that can be applied without a solvent (if you use only Part A)
2. Pure Linseed Oil
This is technically the purest option if you use only the polymerized linseed (though they recommend the Sylvetac resin version for floors).
Polymerized linseed oil or stand oil is a pure, 100% linseed oil formula that is food-safe.
I like the brand Tried and True because it’s 100% pure linseed, and because of their total transparency with ingredients and additives. No driers are used.
For floors, you use the Danish Oil first which is only linseed oil. (Or you can use the oil with a stain in it). And then the Varnish Oil which is linseed oil and Pine Resin (listed on the sales page) or more accurately Sylvetac Resin (listed on the SDS). They also recommend that shellac is used to prime before any of the linseed coats.
Those with chemical sensitivity should test the pure linseed, the oil with the resin, and the shellac.
It’s relatively easy to repair, as you can repair it with a spot treatment.
Color and Finish
It’s a matte finish but the options with a wax can give it a little sheen. It comes in 5 different natural-looking stain colors.
I tested out their pure linseed and linseed + stain option. I really liked the look of the Java stain, it went on beautifully even though I did not sand and prep my wood very well.
You can use it on all wood types including oak.
How to Apply
Sand the floor. They recommend using shellac first as a grain filler for most floors. Burnish (optional). Use Danish Oil (100% linseed oil) as the prime coat. Then 2-3 coats of Varnish Oil (which is linseed oil and pine resin). Buff floor. Full instructions can be found on their website.
If the floor needs repair, you can either spot-apply new oil, or if the whole floor needs redoing, you can sand and reapply (no stripping necessary).
If possible avoid placing area rugs for a week after finishing.
Available through Amazon.com
3. Pure Tung Oil
While this option requires the most coats (wet on wet), it is also the most durable – this finish has historically been used on boats. It does require a solvent and you can choose which one.
Tung Oil is the most durable of the natural oil finishes. It does usually need to be cut with a solvent when used on most hardwood floors. (It’s possible that reclaimed older wood doesn’t need a solvent).
I’ve tested this brand’s tung oil and other brands of tung oil, and this one is definitely lower in odor. And while this option involved a lot more coats than the other oils on this list, the end durability is worth it.
Color and Finish
Tung oil comes in a 100% natural option and in a darker “Dark Tung Oil” which contains an asphalt product to give it more color. You can also use water-based or alcohol-based stains on the wood before applying tung oil.
It produces a matte finish.
How to Apply
Sand floor as you normally would. Apply a generous first coat with a foam roller on a long paint stick. Let the tung oil absorb into the surface for up to 40 minutes. Apply another coat, let it absorb for 40 min, continue until the wood is saturated. Taking a clean rag or cloth, remove any excess tung oil. You don’t need to sand or buff between coats.
It can benefit from then coming back in 24 hours to apply again up to saturation. So it’s a one or two-day affair.
For surfaces that receive moderate to heavy use, you need a minimum of three and up to six coats.
Maintenance coats are on an as-needed basis. When doing a maintenance coat you do not need to sand the surface again. Just add a 2:1 ratio of solvent to tung oil in a thin coat, wipe up the excess, and let it cure for 24 hours.
During the first 15 days of curing you can walk on the floor with socks on. You will want to avoid getting it dirty or allowing liquids to puddle on the surface during this period.
You can move furniture back into the room after applying the tung oil (with plastic sliders under wooden legs). However, keep area rugs and furniture that sits close to the floor off until a full 30 days of curing are complete. You also need to wait 30 days before you can wash the floor.
Citrus solvent takes two about weeks for most people to not smell the orange scent. More sensitive folks might pick up the remnants of citrus for longer.
Part 2: Natural Oil + Solvent Mixes
1. AFM Naturals Oil Wax Finish
This mix of natural oils includes mineral spirits and goes on in 2-3 coats.
AFM Naturals Oil Wax Finish is made from polymerized linseed oil, organic safflower oil, isoaliphate (mineral spirits solvent), tung oil, sunflower oil, carnauba wax, microcrystalline wax, modified soybean oil, hemp oil, and carboxylate metallic salts of calcium, manganese & zirconium.
VOCs are listed as 250g/l.
Colors and Finish
Like all natural oils, it imbues a light ambering matte sheen. This doesn’t come in any stain colors.
Sand. Apply one even coat with a brush or roller and allow the finish to penetrate for 10-15 minutes, apply a second coat (on top of the first wet coat), allow to penetrate for 10-15 minutes then wipe off the excess with a cloth. If the wood is still absorptive, another coat can be applied 24 hours later.
It’s dry and ready to use at 24-48 hours but takes a full 2-3 weeks for a full cure. Put back rugs at 3 weeks.
In the UK through Old Fashioned Milk Paint.
2. Penofin Verde
This mix is based on Rosewood oil but they do not declare all ingredients. It likely contains soy solvent which is quite a mild solvent. A plus side is it could be applied with just one coat.
Another oil to check out is Penofin Verde which is Brazilian rosewood oil mixed with other natural oils. They use “vegetable ester solvents” which could mean ethyl lactate or methyl soyate (i.e. soy solvent, explained here). They say “no heavy metal compounds”, so it could contain metallic driers, we just don’t know which ones.
VOCs are listed at less than 1 g/liter.
Colors and Finish
Comes in 21 natural colors including lightening shades. Matte finish.
Using a brush, pad, or pump sprayer apply a liberal coat to the wood. Allow Verde 10-20 minutes to penetrate into the wood then wipe the surface thoroughly with clean lint-free cloths to remove any excess finish.
They recommend re-coating horizontal surfaces every 9-24 months.
Verde will dry to the touch in 4 hours and is serviceable after 12 hours.
3. OSMO Hard Wax Oil
The strongest in odor of the options I tested, this has the second-best color selection and is a well-known brand that many contractors will be familiar with.
A well-known worldwide brand, OSMO stains are extremely low odor but they are meant to be used with the top coat of Polyx Oil.
The Polyx Oil had a very noticeable solvent odor for me, the majority of that odor did flash off somewhat quickly but the general odor did take more time than I expected to go down in my test.
Polyx Oil Original contains sunflower, soya, and thistle oil, with waxes, including paraffin, plus de-aromatized white spirits (solvent, explained here), siccatives (drying agents, usually metals/minerals), and polysiloxanes. It’s EN 71.3 which means it doesn’t contain any significant levels of aluminum, antimony, arsenic, barium, boron, cadmium, chromium (III and VI), cobalt, copper, lead, manganese, mercury, nickel, selenium, strontium, tin, organic tin, and zinc.
Colors and Finish
I did really like the stain colors I tested of the Wood Wax which comes in bright colors (along with the usual wood stain colors and greys and white).
The Oil Stain is also for floors. It comes in 10 colors including lightening shades.
Polyx Tints is a topcoat and color in one, it comes in more subtle shades of white, light grey, honey, amber, terra, graphite, and black (all in satin).
Wood Wax stains are applied in one coat, followed by Polyx Oil for floors.
Oil Stain is applied in 1-2 coats and is followed by Polyx Oil.
Polyx Tints (stain and topcoat in one) is applied in 1-2 coats.
Polyx Oil is applied in two coats. With Osmo flat brush, floor brush, oil finish applicator fleece (hand pad holder), or Osmo microfibre roller, apply thinly along the wood grain and spread well. Allow to dry for approximately 8-10 hours under good ventilation. After drying, apply a second coat also thinly.
When renovating or recoating an already oiled surface, one coat applied to the clean and dry surface is usually sufficient.
After 2-3 weeks, the surface is fully cured.
Available in the US on Amazon.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.