Restoration Guide: Plywood Siding for Exterior Walls
Editor's Note: This is article 13 of 18 in Chapter 2: Exterior Walls of the Old House Web Restoration Guide. This guide was developed and edited for old homes from original materials in the U.S. Housing and Urban Development (HUD) Rehab Guide.
13. VERTICAL PLYWOOD PANEL SIDING
Section 1--The Basics
Plywood siding was introduced in the 1950s and is a popular building material in many northern states, although its use has dipped over the past decade. As other products, such as fiber cement and vinyl siding, gain market share, use of plywood panel siding is expected to further decrease.
Plywood siding hasn't changed much since it was introduced more than 50 years ago; however, veneer facings are now being added by some manufacturers that extend the life of the siding and increase it's ability to hold paint. Newer products include:
- Simpson Forest Products Guardian
- Roseburg Forest Products Breckenridge
- Stimson Lumber Company's Duratemp
Simpson's Guardian plywood siding includes a craft paper impregnated with resins, while the Roseburg and Stimson products are made with a hardwood overlay that improves durability.
1.1: Types of Plywood Panel Siding
Most plywood panel siding is made from Douglas fir or southern pine veneers. It's sold in sheets in a variety of textures and seam styles. Patterns include:
- Channel grooved
- Rough sawn
In many cases, especially in old houses, the plywood siding was applied directly to the framing in place of plywood sheathing. Plywood panel siding also can be used over masonry walls if furring strips are added to provide a nailing surface. Plywood siding must be primed and painted within a month of being hung, or it degrades due to exposure to ultraviolet rays and other weathering effects.
Section 2--Repairing Existing Plywood Siding
One of the inherent problems with plywood siding is with its vertical lap seams--water tends to find an entry point at these seams, and over time the siding often expands and bulges at seam lines. Any remodeling project that includes vertical plywood siding most likely has areas where the siding hasn't stood up to the elements--one reason why other horizontally run siding products have diminished vertical plywood siding's market share.
In addition to seam lines, siding often swells and expands along stud lines, forcing siding nailing away from the framing members. Remodeling homes with plywood siding should include time spent with a hammer to snug up the plywood paneling. Using a 2x4 inch block to beat the siding tight against wall framing eliminates chipping the paint off nail heads.
The best way to replace damaged sections of plywood siding during a home renovation is to remove the whole panel. Cutting out damaged sections and replacing them results in an unattractive patch that's prone to leakage at the new seam lines.
2.1: It's All in the Groove
Depending on when the siding on your home restoration job was produced, you may have a difficult time finding a similar siding pattern since some siding patterns are no longer produced by current manufacturers. There are some specialty contractors available that can manufacture outdated siding groove patterns. Another option is to find the best-available matching product, remove all the old siding from an entire wall, and replace it with the new pattern. Although it won't match the rest of the house, it won't be as noticeable as a different pattern on the same wall section.