If you have a birdhouse in your yard, it may be a good idea to seal it to protect it. But what kind of products can you use to seal your birdhouse?
This article will give you more information about whether you need to seal your birdhouse in the first place and, if you do, what products you should use. Read on to learn all about the best bird safe wood sealers for birdhouses.
Do You Need to Seal a Birdhouse?
In some cases, yes, but it all depends on the type of wood that your birdhouse is made from. Natural, untreated wood is prone to damage when it is exposed to the elements, so it will need to be sealed. However, a lot of wood that is used for exterior projects has been pressure-treated beforehand.
During this process, high pressures are used to force chemicals such as ACQ (alkaline copper quaternary) into the wood to protect it from moisture damage and UV rays. So, it will last longer outside without a sealer. Hardwoods are more robust too, so they will last longer without protection.
However, even if your birdhouse is made from pressure-treated wood, sealing it is still an option. It will stop any moisture from getting inside and make it last much longer.
The Importance of Sealing a Birdhouse
When your birdhouse is outside, it is constantly exposed to moisture, which soaks into the wood and eventually causes it to rot. UV rays from the sun will dry the wood out and cause cracking and warping. The wood may also lose its color over time and turn gray.
When you seal the wood with a natural wood oil or a sealer, you can reduce the amount of water that the wood takes up and protect against UV damage. Ultimately, this means that your birdhouse lasts a lot longer.
Wood oil enhances the natural color and brings out the grain of the wood too, so it will make it look more attractive.
What is the Safest Type of Sealer for Birdhouses?
When choosing a sealer for birdhouses, you need to consider whether it is safe for the birds. Anything that is highly toxic creates a problem with off-gassing and the toxic fumes could harm the wildlife.
Natural wood oils like linseed oil and tung oil are the safest option. Boiled linseed oil does contain some harsh chemicals, so it’s important that you let it fully dry before the birds use it, but it is still safe.
Shellac and other clear varnishes are also safe for birds, but only once you have let them dry and cure properly. While they are still wet, they can release toxic fumes that are harmful to the birds.
10 Best Bird Safe Wood Sealers
1. Sunnyside Corporation Pure Raw Linseed Oil 
Raw linseed oil is excellent for protecting wooden birdhouses. It has a nice natural wood tone and it penetrates deep into the wood to protect it. This Sunnyside Corporation Linseed Oil is an excellent quality oil that will give you long-lasting protection for your birdhouse.
Be aware that raw linseed oil has a very long drying time, so you need to give it 2-4 days before you can use the birdhouse outside. Although this is a long time for it to dry, it gives a chance for the oil to settle deep into the wood and give great protection. When applying, use a cloth to keep rubbing layers in until it stops soaking in and it beads on the top instead. Then, you can wipe off the excess.
2. Hope’s Pure Tung Oil
Tung oil is another excellent natural wood oil for your birdhouse. This Pure Tung Oil from Hope’s gives a clear finish, in comparison to the slight yellow tint you get from linseed oil. It’s got great moisture protection and is completely non-toxic, so it’s safe for the birds. This product also takes a while to dry, so don’t be alarmed if it still feels slightly sticky after a few days. However, you can recoat after around 24 hours, even if it is a bit tacky. It’s an oil product, so it doesn’t need to be fully dry before recoating.
3. Rust-Oleum Zinsser Bulls Eye Clear Shellac
This Rust-Oleum Clear Shellac is easy to use and it gives a great protective layer. It dries much quicker than wood oils, so you can get a few coats done in a single day and start using your birdhouse as soon as it is dry. This product is thin enough to be applied with a sprayer, which makes it easier to get an even coverage.
Unlike wood oil, shellac forms a film over the top of the wood rather than soaking into it and protecting from within. This means that you get a solid barrier against moisture, making it a better choice in very rainy climates. This is a clear option but you can also find some tinted options on the market too. You will get a glossy finish with shellac, but if you want to dull it, you can use some fine steel wool to take the sheen off.
4. Minwax Helmsman Spar Urethane Aerosol Spray
Spar urethane is another durable clear coat that forms a protective layer on the surface of the wood. If you want an easy option for sealing your birdhouse, this Minwax Helmsman Spar Urethane Aerosol Spray is so easy to apply, just spray it on. You’ll get a strong coating that offers excellent UV protection as well as waterproofing and you don’t need to worry about brushes or cleanup either.
You can use clear coats like spar urethane after staining too, so if you want to change the color of your birdhouse and then protect it, this product is ideal.
5. LinSheen Boiled Linseed Oil
This LinSheen Boiled Linseed Oil is excellent if you want the nice finish and protection of linseed oil without the long drying times. Although it is called boiled, it has actually been treated with hot air and additives to reduce the drying times. It goes on the same as raw linseed oil but it dries much faster.
You should know that some of the petroleum-based additives are potentially harmful, so you need to let it dry in a well ventilated area before you let the birds use it. However, once it has dried properly, it’s perfectly safe. This linseed oil has a nice clear finish that highlights the wood underneath.
6. TotalBoat Gleam Marine Spar Varnish
The TotalBoat Gleam Marine Spar Varnish is a brilliant product that combines tung oil and spar urethane varnish in one. It’s designed for protecting boats, so it can easily stand up to the moisture from normal weather conditions in your yard. The tung oil soaks into the wood, gives it a nice amber color and protects from moisture and UV damage. The spar urethane then forms a protective barrier over the top and locks in the oil, while also giving another layer of protection.
If you’re looking for something incredibly hardy that will make your birdhouse look amazing and protect it for a long time, this is the product for you. It’s also available in gloss and satin, so you can decide what finish you want.
7. Howard SunShield Outdoor Furniture Wax with UV Protection
Satin furniture wax like this Howard Sunshield Outdoor Furniture Wax is good for protecting wood and bringing out the natural grain. It’s also very scratch resistant, especially compared with clear coats, which is a bonus for a birdhouse. This product also has excellent UV protection so the wood will stay looking fresh for longer.
It is a combination of carnauba wax, beeswax, and orange oil, so it not only protects the wood but the orange oil nourishes it too, to stop it from drying out.
8. Varathane Diamond Spar Urethane Satin
This Varathane Diamond Stain is a great water-based spar urethane stain that offers superior protection. It’s a very quick drying clear coat, so you can do up to 3 coats in a single day. It is also specially formulated to avoid yellowing and give a nice satin finish. The water-based formula also makes for easy clean up. If you want a spar urethane coating that is easy to apply, the Varathane Diamond is one of the best.
9. STAR BRITE Premium Golden Teak Oil
Teak oil is a combination product usually made from linseed oil and tung oil, with some mineral spirits and other additives. The mineral spirits thin it out slightly, so it applies easily compared with thicker all-natural oil products. The STAR BRITE Premium Golden Teak Oil is one of the best teak oils on the market. It’s made from high quality linseed and tung oils that give long-lasting protection and a great golden color.
Teak oil is one of the best exterior wood coatings because you get the best features of natural wood oils with a few additions to make them perform even better. The slightly thinner product also soaks into the wood easier, so application is simple.
10. Seal It Green Garden Box Sealer
The Seal It Green Garden Box Sealer is designed for garden planters, but it’s great on other exterior wood fixtures, like birdhouses. It has a non-toxic formula so it doesn’t kill off vegetables, and that means that it’s also safe for birds. It is made from a combination of different tree oils and some other plant based materials, like coconut oil.
Bird Safe Wood Sealers for Birdhouses FAQs
What Sealers are Toxic to Birds?
Some sealers are toxic to birds and you need to be very careful when sealing your birdhouse. Using these products could harm or even kill local wildlife in your garden. Toxic wood treatments to avoid are:
- Lacquers
- Acrylic based paints
- Oil-based stains (water-based products should be non-toxic but double check the label)
- Polyurethane (this shouldn’t release VOCs once it is fully dried, but should be avoided if you want to be safe)
Can You Stain a Birdhouse?
Yes, you can stain a birdhouse to give it some color and if you find a waterproof and UV resistant stain, you can protect it at the same time. However, many oil-based stains are quite toxic and shouldn’t be used for birdhouses. If you are going to use stain, look for water-based products and check the tin to look for guidance about toxicity.
Is Wood Glue Safe for Birds?
Yes, PVA wood glue is safe for birds as it has very low toxicity. So, if you need to make repairs to your birdhouse, make sure you use wood glue and nothing else.
Final Thoughts
Sealing your birdhouse will protect it from the elements and make it last a lot longer without rotting or cracking. Wood oils are a great natural option but if you want easy application and long-lasting protection, clear coats like spar urethane are excellent.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.