Low-VOC and non-toxic sealers (and stains) for log cabins fall into two categories: natural oil penetrating sealers and low-VOC synthetic sealants.
For the exterior, we want something as durable as possible. There are two main options here. The first is the all-natural tung oil mix made for exteriors and the second is a low-VOC synthetic from Vermont Natural Coatings.
While there are other options in both categories – other brands that make penetrating oil sealers and other brands that make water-based or oil-water hybrid sealers, these are my top brands and the best in each class.
For the interior, you can use something that is not quite as durable. This allows for more options that are lower in odor than the exterior products. We still have the same two categories, natural penetrating oils and synthetic sealers.
I also cover stains, some are a stain and sealer in one and with other options, you need to add the stain first.
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1. Natural Penetrating Oil
Penetrating oils come in all-natural formulas. These oils naturally polymerize and form durable coatings. Tung oil is the most durable of the oils and is suitable for exterior applications. It is almost always mixed with a pine or citrus solvent when used on wood, which can be too strong for some people, at least at first.
If the log cabin walls are raw wood with no finish on them you can use a penetrating sealer. If you are unsure if the wood is already sealed, you can do a water test – put some water on the surface and see if it absorbs. If it does, then penetrating oils should work well. If it doesn’t absorb, there is some kind of sealer or finish on the logs that would need to be removed prior to using any penetrating finish.
Penetrating Oil Exterior Log finish
Outdoor Defense Oil (ODO), a natural tung oil mix, is a great sealant for the exterior. If the logs are super dry, you might even be able to use Pure Tung Oil for the first coat or two and then follow up with ODO to top off the wood. For the log ends, the Pure Tung Oil would be best since the “end grain” of the log is super absorbent and will take the tung oil without diluting.
Tung oil is a natural choice but it’s still very durable and holds up well. The Outdoor Defense Oil is made from pure tung oil, pine oil, and zinc. The pine and zinc give it natural anti-fungal properties and some UV protection.
One of the benefits of the tung oil on log homes is it is partially vapor permeable which is usually a good thing for moisture management. Also, tung oil is flexible, so as the wood expands and contracts with the weather the tung oil will also flex with the wood rather than being rigid and cracking.
I would expect annual maintenance for the best protection.
Stains for Natural Oil Finishes
Tung oil naturally darkens the wood somewhat. If you want an even darker color there are some more options.
You can also paint the exterior of the cabin with Milk Paint! The Milk Paint is very colorfast since they use pigments rather than dyes. You do need to seal over the Milk Paint with the tung oil to give it weather/water resistance.
Their pigments can also be used to tint the tung oil, but if you add too much though you’re essentially creating an oil-based paint.
Interior Penetrating Oil Log Finish
For the interior, any of the penetrating drying oils will work well and you don’t need to fully saturate the logs, usually 1-2 coats will do.
The Hemp Oil is nice for the interior because it doesn’t require any solvent so it is low odor compared to tung oil and is lower in odor than linseed as well.
If you do prefer linseed I like a pure linseed oil with no additives like Tried and True.
If you want to paint your interior walls be sure to use a breathable paint, they are listed here.
2. Low-VOC Synthetic Coating
If you don’t want to go with the natural oils, there are low-VOC synthetic formulas. Some are water-based and some are an oil/water hybrid. I really like the company Vermont Natural Coatings as their products have been both low odor and competitive with more toxic sealers in terms of durability.
Low-VOC Exterior Log Finish
On exterior spruce/fir/pine logs that do not already have a stain/sealant on them, you can use SunCare900 Primer (1 coat), followed by Bohme Ligno Exterior Stain, a super low-VOC water/oil hybrid exterior grade stain and topcoat in one (2 coats).
Choose one of the colors to mask/prevent the natural graying of the wood underneath.
Low-VOC Interior Log Finish
For the interior, you have more choices. Really any acrylic or polyurethane low or zero-VOC coating will do. You can choose from a number of brands. I still really like Vermont Natural Coatings but some people do react to this (possibly to the whey). So you may want to test multiple options if you are sensitive to chemicals.
These are my top picks:
Vermont Natural Coatings PolyWhey was my top choice for a durable coating that holds up well on wood and is very low odor. It has the best combo of durable and low odor that I have found.
ECOS varnishes, which are acrylic-based, are super low toxin. In my experience, they are not as durable as the polyurethane alternatives but that’s not usually a problem on walls.
AFM Polyureseal is liked by many. It is a very tolerable formula by a high-quality brand. This brand is a durable low toxin polyurethane finish for wood floors.
Very low odor polyurethane and acrylic options also include BioShield Aqua Resin, Earthpaint Aqualine, Earthpaint Easy Safe 1K, and Vermeister. I compare them all in a dedicated post if you want to consider more options.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.