Bird-Safe Wood Sealers (For Birdhouses)

The following list of brands of sealers, stains and paints are safe for a birdhouse and have been reviewed by our resident veterinarian.

We want to select a sealer and stain that is 0-VOC and safe for birds.

It’s important that it does not contain pentachlorophenol preservative (source).

It’s recommended to seal or paint the outside only.

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Non-Toxic Stains and Paints for a Birdhouse

1. Rubio Monocoat Linseed Oil

Most linseed oil formulations are not meant for exterior wood. Many brands can go moldy in outdoor conditions.

Rubio Monocoat Hybrid Exterior Wood Protector is a one-part system and requires no catalyst or accelerator.

It comes in clear and colored stains that are safe for birdhouses, says the company.

It holds up in outdoor conditions and won’t go moldy.

Curing times without the Oil Accelerator B is 7 days.

(I would recommend using it without the optional accelerator, since the accelerator is a solvent).

It’s faster to cure than Tung Oil, plus you only need one coat.

They also said in an email that the new DuroGrit would also be safe for birdhouses (and it’s also based on linseed oil).

2. Natural Tung Oil

Natural Tung Oil can be used on birdhouses.

It’s a very durable oil that holds up well in outdoor conditions.

It does usually need to be mixed with a solvent.

You can use their mix with natural Citrus Solvent or their Outdoor Defense Oil (which is Tung Oil and Pine Oil as the solvent).

Unless the wood is very old and dry, in which case you can likely use pure Tung Oil with no solvent.

Apply Tung Oil/Tung Oil-solvent mix to the wood.

Let the oil absorb into the wood.

Repeat the oil application as many times as necessary until the surface doesn’t absorb any more oil.

Once you reach the point of over-saturation, wipe away the excess oil and let the oil begin the curing process.

It takes 7 to 15 days to be dry to the touch and 30 days for complete curing before you can put it in outdoor conditions or wash it down.

3. Milk Paint

If you want to paint your birdhouse, you can use Milk Paint under a natural drying oil like Tung or pure Linseed.

The drying oil over Milk Pint is necessary to protect the paint in outdoor conditions.

It also darkens and dulls the colors.

The Real Milk Paint recommends cleaning the wooden birdhouse with Tri-Sodium Phosphate.

Mix Real Milk Paint in a 1:1 ratio with water and let the foam diminish for 15 minutes after mixing.

Outdoor Additive is safe to use on birdhouses, they say, and this can help reduce any knot bleed-through and tannin discoloration over time.

Coat the surface once and let it dry for roughly an hour, then add another coat and let your project dry overnight.

Milk Paint requires that you add a finish to protect it from direct sunlight and weather.

Tung Oil (the natural type in the section above) can go over Real Milk Paint.

You may need a reapplication every now and then.

Paint colors for birdhouses: Birds avoid bright unnatural colors since they are too obvious to predators (source). If you want to paint it, earth tones (but not black) are best (source). Though different species prefer different colors (or prefer unpainted birdhouses).

4. ECOS Paints

ECOS Paints Pet Dwelling Primer and Pet Dwelling Paint are a 0-VOC acrylic paint and primer that are safe for all animal enclosures including birdhouses.

ECOS recommends semi-gloss for a birdhouse.

On raw wood, use the primer followed by two coats of paint.

Avoid getting the birdhouse wet for the first 30 days (which is how long it takes for a full cure).

Don’t Use On Birdhouses

• Shellac – shellac doesn’t hold up in outdoor conditions.
• Most linseed oil – most linseed oil brands can go moldy in outdoor conditions.
• Teak Oil or other tung oil mixes from conventional stores – I would not go with an oil-solvent mix with synthetic solvents or unknown ingredients as they could be toxic to birds.

Safe Wood Species to Use for Birdhouses

• Cypress, white cedar, hemlock, or local weather-resistant wood with low toxicity. (source)
• Another source says softwood such as pine is fine for smaller nests, but cedar, redwood, or cypress should be used for larger boxes. (source)
• Cedar, redwood, and cypress are durable enough outdoors to not need a protective sealer.
• If you are looking for an indoor birdhouse for a pet bird, the best wood types include maple, poplar, and birch. (source)
• Materials not to use:
• Do not use pressure-treated wood which is toxic to birds.
• Don’t use wood that has been treated with pesticides.
• If you use recycled wood, make sure it was not pressure treated, treated with creosote, or painted with paint containing lead. (source)

Sources:

https://www.massaudubon.org/nature-wildlife/birds/birdhouses

https://www.audubon.org/news/how-build-bluebird-nest-box

https://www.wintuaudubon.org/Documents/DefinitiveGuideToBuildingYourOwnBirdhouses2013.pdf

https://www.massaudubon.org/nature-wildlife/birds/your-guide-to-birdhouses

Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.