Sealing plywood for longer life. plywood is an important and stable building material, comprised of many different veneers glued together at right angles. these layers provide dimensional stability, but leave the edges, which expose all of the laminate sections, particularly vulnerable to water damage.. Plywood is a flexible wood material used in the construction of houses, sheds and other buildings. the material, like other wood, is not resistant to moisture and other weather elements when used outdoors. to keep exterior plywood from rotting, it is important to seal the wood with a water-repellent. When painting exterior plywood, it's important to take the proper steps toward preparation before you even think about applying any paint. if you want your paint project to last, you must thoroughly seal the exterior plywood to protect it from varying weather and temperatures..
Plywood is a durable material for projects, but it is necessary to seal plywood to protect it against water damage and rotting, and to ensure a long-lasting finish. once it is sealed, you may finish your project with paint or polyurethane. you may find the materials for sealing plywood at any hardware or home improvement store.. Types of waterproofing. many types of waterproofing are available to protect plywood. the most common type sold in home improvement stores is the paint-on or spray-on type of waterproofing.. Exterior plywood is commonly used for siding. for this application it should have a rough sawn surface (textured) or be overlaid with a stabilized, resin treated paper called medium density paper overlay (mdo). smooth sanded plywood is not recommended for siding, but it may be used for soffits..