Damage to plywood siding often happens due to sun exposure. Sunlight and moisture can damage the surface of the plywood siding causing cracks and warping. Fixing the sun damage is easy to do, and can be done with wood cleaner, scrubbing, and sandpaper.
Step 1 - Remove Damaged Plywood
Follow the instructions that come with a bottle of wood cleaner and mix a batch following the ingredients. Brands may vary so follow the instructions on the bottle. Apply the solution to the damaged plywood siding. You will want to leave the solution on the plywood for about a half an hour.
Step 2 - Scrub the Plywood
Scrub the plywood siding with a scrub brush. You will need to do so with a little force. All the dead wood fibers from the plywood should come right off from the scrubbing and all that you will have left is healthy wood.
Step 3 - Rinse the Plywood
Use a hose to rinse the plywood siding. If the hose you are using has pressure control, you can higher the pressure of the water to ensure a clean area.
Step 4 - Apply Wood Brightener
Sometimes the plywood can darken after cleaning. If you are not happy with the dark color, than you can apply wood brightener to the plywood. If you choose to use wood brightener, leave it on the wood for 45 to 50 minutes or as recommended by the instructions. Rinse the plywood again with water.
Step 5 - Apply Putty to the Plywood
Next you will apply wood putty over any visible areas of damage on the panels. You want to be generous with the putty and fill up any holes or damage. If you are having difficulty getting the putty into the tiny areas, you can use a knife to aide you. Dab a little putty on the end of the blade of the knife and carefully fill up the crevice. Putty varies on how long it takes to dry. Twenty-four hours is usually enough time for the putty to completely dry.
Step 6 - Sandpapering Damaged Plywood
Any really damaged plywood will need to be sanded down with sandpaper. With the coarse side up, you can begin to sand down the plywood. Don't use an up and down motion because this can give you an uneven finish. Always use circular motions to ensure a smooth surface. Don't be afraid to use a little force, you want to make sure the putty is evenly plastered upon the plywood siding.
Step 7 - Remove any Damaged Plywood
Use the back of a hammer or a pry bar to remove any damaged plywood. If there are a lot of boards that need to be replaced, you should complete this step first to save time. You don't want to end up replacing many of the boards you started to sand down. Use a hacksaw to remove any exposed nails and dispose of them properly. Replace any damaged siding with new boards. Secure these boards with nails.