Wood Structural Panel Siding
Wood Structural Panel Siding
Wood structural panels used as siding are made from plywood. They are most commonly seen as 4×8 foot and 4×9 foot vertical panels. They come in a wide variety of textures and panel patterns. Thickness is between ⅜ and ½ inch. Panels should be installed by fastening siding to walls over a water-resistive barrier. Plywood was first available in the late 1800s, became widely available in the 1930s, and was most popular during 1940s through 1990s. It is currently available, but has a small share as siding in many markets. Do not describe this material as hardboard or wood siding. Plywood siding is often referred to as T1-11 because the indentations can be 1 inch wide and the raised section can be 11 inches wide. Wood structural panel siding comes in many different textures and panel patterns so the term T1-11 is not an accurate description of this material.
Wood structural panel siding should be installed according to manufacturer’s instructions. These instructions will vary based on the manufacturer, the model of siding being installed, and the location of the house.
Typical Defects Typical siding defects that home inspectors should report include:
- inadequate clearance above grade, hard surfaces, and roof coverings (2 inches above hard surfaces and above roof coverings, 6 inches above grade),
- absent and deteriorated flashing and sealant around doors, windows, other penetrations, and at horizontal joints between sheets,
- absent and improperly installed flashing and kick out flashing at wall intersections,
- damaged and deteriorated siding; deterioration often found near the bottom edge of the siding,
- improperly installed fasteners (e.g., wrong fastener type, improper location, over and under driven),
- absent or deteriorated paint at the bottom edge.
Standards (1) IRC 2018 Section R703; (2) manufacturer’s instructions.
