Bamboo is a gorgeous material for outdoor furniture, products, and fencing, but the outdoors can be harsh, and bamboo needs protection from the elements! With proper protection, your bamboo products could last many seasons.
You can seal bamboo for outdoor use with bamboo sealer, exterior wood sealers, oil-based exterior varnish, marine varnish, spar urethane, outdoor polyurethane, or tung oil. You’ll need to prepare your bamboo by sanding and cleaning it before you apply the sealer.
Bamboo has multiple sealer options; you’ll need to decide on one before diving into the next steps. This quick step-by-step guide will provide you with everything you need to know for sealing outdoor bamboo, from furniture to fences.
Sealing Bamboo For The Outdoors
Bamboo has a natural waterproof silica layer, but it disintegrates rather quickly and will not last the trials of adverse weathering. As for some bamboo products like furniture, the silica layer is worn away during production, so you must protect it with a sealer if you want to keep them outside.
Bamboo will only last up to two years without sealer, but if protected, it can last up to twenty years. A proper sealer will make your bamboo durable and keep it looking snazzy for years to come. Some sealer options last longer, while others look better, but luckily there are plenty of options!
You must prepare your bamboo properly and apply the chosen sealer correctly. You can add a layer of wood oil or wax to finish your bamboo product for aesthetics and extra protection. Bamboo aftercare is also something to think about.
Step 1: Choose The Right Sealer
Before jumping to the easiest sealer option, some choices might have aspects that don’t suit your needs. Some sealers require multiple layers or a long drying time. Some sealing choices also have a more natural finish than others.
These are your bamboo sealing options:
- Bamboo Sealer: Some hardware stores sell a sealer made explicitly for bamboo, formulated to seep into bamboo fibers, protecting it against moisture and UV rays while keeping a natural appearance. Bamboo sealer options are limited and often expensive.
- Exterior Wood Sealers: You can use a wood sealer made specifically for exterior use. You should look for one that includes moisture, mildew, and UV protection. The downside is that exterior wood sealers are not as durable and don’t have high UV resistance
.
- Oil-Based Exterior Varnish: Oil varnishes are ultra-durable, and water-resistant, shielding bamboo from UV rays and temperature fluctuations. These varnishes require a long cure time, have strong fumes that require caution and may be glossy.
- Marine Varnish: Marine-grade varnishes are long-lasting and weather resistant, making them suitable for bamboo items exposed to extreme outdoor conditions, such as coastal environments. Although this is the most durable option, it is difficult to apply, glossy and is subject to yellowing over time.
- Spar Urethane: Spar urethane is a clear protective finish commonly used for exterior wood surfaces. It is highly durable against moisture, UV rays, and temperature changes. The downside is that it is challenging to apply evenly, and you need a VOC-free one, or it can cause air pollution. Spar urethane is incompatible with some paints and coatings if you plan to paint afterward.
- Outdoor Polyurethane: Polyurethane is a resilient clear coat that protects bamboo against water, sunlight, and wear. Make sure to choose a polyurethane labeled for outdoor use. The qualities resemble spar urethane, but it is less yellow.
- Tung Oil: This is the most natural-looking sealer and is easy to apply. Tung oil offers a matte finish that protects bamboo from moisture and UV rays but isn’t as good as the other sealer options. Tung oil also requires more regular maintenance.
Step 2: Prepare The Bamboo
Clean the bamboo to remove dirt, dust, and debris using water and a mild detergent with a clean cloth or a brush. Sand any rough spots or splinters using medium-grit (60 – 80) sandpaper. After ironing out the imperfections, use fine-grit (200 – 240) sandpaper to smoothen the surface. Remember to wipe the dust!
If your bamboo still has a silica layer, you’ll need to sand it off; otherwise, the sealer will wear away as the silica does. You must also ensure your bamboo is 100% dry before sanding, or you will damage it. Always sand with the grain of the bamboo.
Step 3: Apply The Sealer
Any sealer you decide on will come with its own instructions that vary per manufacturer. Follow all instructions carefully and follow the safety guidelines as necessary. Apply all sealers evenly in the direction of the grain.
Feel free to test a small area on your bamboo product before committing to the sealer!
Step 4: Let The Sealer Dry And Cure
Most bamboo sealers require multiple coats; you must wait for each to dry between applications. The more coats you have, the longer the cure time will be. You should ensure your sealed bamboo doesn’t get wet during the application and dry time; otherwise, you’ll run into issues!
Note that multiple thin coats of sealer are better than one thick coat. Some sealers recommend gently sanding with fine-grit sandpaper between coats to ensure a smooth and adhesive finish.
Step 5: Apply Finishes
To extend the lifespan of the sealer, you can introduce regular touch-ups with wax or tung oil to your bamboo product. You can also play around with appearances and textures.
Some additional finishes can include:
- Wax
- Tung oil or any other wood oil.
- Stain
- Paint
- Matte or satin topcoat
- Resin
- Clear lacquer
Step 6: Bamboo Maintenance
To ensure your bamboo lasts a lifetime, you could apply protective finishes yearly to prolong the sealer effect and lessen your reapplication frequency. Once you notice the sealer starting to wear away, it’s recommended that you reapply a coat or two again to prolong the bamboo’s lifespan.
|
Sealer |
Coats |
Dry and Cure Time |
Approximate Reapplication Frequency |
|
Bamboo Sealer |
1-2 Coats |
Dries in 1-2 hours, cures in 24-48 hours. |
1-3 years |
|
Exterior Wood Sealers |
2-3 Coats |
Dries in 1-2 hours, cures in 24-72 hours. |
2-4 years |
|
Oil-Based Exterior Varnishes |
2-3 Coats |
Dries in 8-12 hours, cures in 7 to 14 days. |
2-4 years |
|
Marine Varnish |
3-4 Coats |
Dries in 8-12 hours, cures in 10 to 21 days or more. |
3-5 years |
|
Spar Urethane |
2-3 Coats |
Dries in 4-6 hours, cures in 7 to 14 days. |
2-4 years |
|
Outdoor Polyurethane |
2-3 Coats |
Dries in 2-4 hours, cures in 7 to 14 days. |
2-4 years |
|
Tung Oil |
3-5 Coats |
Dries in 24 hours, fully cures in 7 to 30 days. |
1-2 years |
Wrap Up
With ample sealing options within your reach, your bamboo products will last a long time outdoors – maybe even 20 years! Always prepare your bamboo and follow your selected sealer instructions for the best results.