They are treated so that they survive exposure to rain, humidity, and extreme weather conditions without decaying. These types of plywood are mostly resistant, particularly marine plywood and BWP, boiling-proof plywood. It is waterproof, adhesive-treated, and chemical-treated, resisting warping, swelling, and breakdown, making it fit for use in outdoor or waterproof circumstances such as boats, roofing, or external walling.
Marine, BWP, or exterior-grade plywood is the best type for outdoor use. Such plywood types are treated to give a surface that is quite resistant to moisture and exposed to changing weather conditions. Marine plywood is ideal for areas of humidity and water, while BWP offers durability even for general outdoor applications. Both types are durable and not prone to degradation by rain, wind, and temperature, among other factors.