T1-11 is available in two grades: plywood and OSB. Plywood is the superior material, while OSB is the least expensive. Plywood consists of a series of fine layers of laminated wood, while OSB is comprised of a series of wood chips and strips that are glued together. Plywood holds a finish better than OSB, and plywood affords with homeowner with the benefit of being stainable. OSB board cannot accept a penetrating stain evenly and must be painted to avoid damage from moisture.
Plywood T1-11 can accept stain or paint, while OSB cannot accept stain and must be painted. The inherent expansion and contraction of T1-11 makes it difficult to maintain a painted finish. Stain is the better choice for plywood T1-11. Unfortunately, the OSB version of the material will only take paint. Prime the board with a good exterior primer and use 2 coats of exterior paint. Expect to sand and repaint every few years to maintain the board’s water-resistance.
Keep your T1-11 siding finished and keep whatever coating you choose well maintained to preserve the water-resistance and protection for harmful ultraviolet (UV) rays from sunlight. Moisture allowed to seep into T1-11 siding will cause the board to expand, and checks and fissures can appear in boards left exposed to sunlight.
T1-11 emulates the appearance of a series of vertically aligned siding boards. Plywood T1-11 is available in both a sanded and a rough-hewn variety. The choice between the two is purely aesthetic; both types of material perform similarly.