Plywood siding is usually applied during the construction process of a home. The plywood siding provides a case and barrier to the frame for the structure. However, it is imperative to seal the wood to prevent rotting, warping and erosion. Absolutely no moisture should penetrate the wood. The sealant will prevent this from happening and can be applied with a brush or standard paint roller. You may find the materials for sealing plywood siding at most hardware and home improvement retail stores.
Pour the plywood sealer into the paint pan. If sealing the plywood siding outdoors, which is most likely, avoid performing this task on a windy day. Sanding the wood is not necessary, as plywood siding is structural, not cosmetic. A smooth finish is not imperative. It is recommended that you apply the sealant prior to installation.
Dip your paint roller or brush into the pan with the plywood sealer and saturate the roller. Apply the sealant in up and down motions with each stroke crossing the previous stroke slightly. This ensures a smooth and even finish. Be sure to use dust sheets to avoid staining on the floor.
Allow at least one to two hours for the plywood sealant to dry completely. Apply a second coat once drying is complete. To paint all sides of the plywood, finish one side first then flip over and repeat the same process. The same number of coats should be applied to every side.