When restoring an outdoor pergola, examine the structure and evaluate its general condition. This will tell you if it is sound enough to justify the time and materials it may take to restore it. If not, you may want to replace it with a new one. Once you've determined the pergola is worthy of being saved, your project will be similar to most outdoor wood restoration projects. The process is fairly simple if the wood has been left in its natural state.
Step 1 - Hose it Down
Remove all attachments to the pergola. Be careful with clinging vines since you may need to do some unwrapping that could cause shock to the plant. If possible, remove any lattice side walls the vines cling to, concentrating on the pergola post and beam wood. Once you have cleared the pergola, use a water hose to wash away any dirt or debris.
Step 2 - Clean the Wood
Use a commercially available wood or deck cleaner that will be easy to use. These solutions do a good job removing built-up grease, grime and dirt, helping prepare the wood for a refinish. Either use a synthetic paint brush to apply the solution using long, even strokes or, better yet, place the solution in a spray bottle that you can evenly spread across the wood surface area. Start at the bottom, working upward to prevent streaking. Use a side-to-side spraying motion.
Step 3 - Soak in
Wait a few minutes while the cleaning solution soaks into the wood. Use a flexible bristled brush to loosen all dirt and debris. Use a small brush, like a toothbrush, to scrub hard-to-access areas. Remove any damaged wood particles and splinters carefully. Make sure to wear gloves to protect your hands.
Step 4 - Rinse
Rinse the solution scrubbed wood with your water hose. Carefully examine all areas for spots missed and repeat the soak and scrub step above and rinse again. Once you’ve arrived at a satisfactory level of wood cleanliness, allow the furniture to completely dry; 24 hours should do the job.
Step 5 - Sand the Wood
After the wood has completely dried from your soak and shine scrubbing, the wood grain should stand out. Smooth the wood using rough sandpaper but don’t overdo it. You want to rough up the wood just enough to get it to absorb a coat of finish.
Step 6 - Color it
Consider adding color to your pergola wood. Adding color will help protect the wood while adding a little extra enhancement. Use a gel stain because it won’t drip. Use an applicator pad on larger, wider surface areas while employing a paintbrush along the board and beam edges. Work the applicator pad in a circular motion to successfully get the stain into the wood grain. Make sure the stain is completely dry. Apply a protective coating of clear sealant.
Using a high-pressure water hose can help speed up the cleaning process, but be careful using it during the rinse stage.