While your bamboo wicker furniture should always sit under a patio awning or be covered in wet conditions, you should still seal it to protect the surface from humidity and rain. Moisture exposure is perhaps the quickest killer of outdoor wicker furniture. Fortunately, adding a proper sealer is neither hard nor time-consuming. Follow the instructions below and keep your wicker furniture that much safer.
Clean the Wicker Furniture Thoroughly
Remove any dirt and debris on the furniture pieces using a vacuum cleaner with a long-bristled head. This will be able to get into all those hard-to-reach nooks and intersections of the wicker weave. Wipe any spots and stains on the surface with a damp cloth with vinegar or a mild detergent. Then, rinse the surface thoroughly with cold water. You can also gently sand any stained spots with 220-grit sandpaper before sealing; just make sure you wipe away any dust created by sanding before you proceed.
Check the Wicker for any Damage
Look over each piece of furniture before you continue to add a sealer to it to ensure it has no wicker-weave or frame damage. If you find any, repair it if you can; if not, you may have to replace the piece altogether.
Apply Water Sealant
You can use either tung oil or a clear lacquer sealant for ample water protection. Tung oil can be obtained at a building supply center; it comes in a can and can be brushed on thickly with a natural-bristled paintbrush. Make sure to apply the tung oil all over the chair, including the front, back, and beneath. Apply it twice a season, in spring and late summer.
Clear lacquer can be put on either with a brush or from a spray container. Be certain to turn the chair and use firm but steady pressure on the lacquer can if you're using one. You can apply tung oil this way as well, diluted with water in a 1:10 ratio in a garden sprayer bottle. Regardless of which of these you choose, make sure you apply them outside or in a well-ventilated space.
Other Sealing Options
Several types of paint are effective as a water-resistant coating on bamboo wicker when applied all over the item, including underneath the seat and all over the legs. These include oil-based paints and others recommended for wicker.
Spray the paint from an aerosol can into the air near the chair so the paint falls lightly onto it. This saves time by minimizing drips, touch-ups, and recoats. Apply two full coats and ensure the paint dries completely between each. Repaint the furniture, as needed, every three to four years with a top-quality paint.
Marine varnish can be applied directly to unfinished bamboo or it can be used to enhance the water-sealing abilities of any paint. It will alter paint color slightly but this will not be noticeable if you varnish the entire item. Allow 12 hours for the furniture to dry when you're finished.
Spar urethane is a little different than polyurethane. It dries to a clear, more flexible finish, so it works well for wicker furniture that extends and flexes as people sit or lie on it. Spar urethane also works well to prevent cracking and splitting. Reapply this coating over the whole surface of the furniture piece every two years.
Tip: Avoid allowing your bamboo wicker furniture to stand out in driving rain or fog even after water sealing.