Reclaimed Sinker Cypress Used for Exterior Siding of the Center
The Living Building Challenge (LBC) requires as many elements of the design as possible to be composed of recycled, reclaimed or salvaged materials. This minimizes the carbon footprint that is created by new manufacturing processes and maximizes the retention of our natural resources by reusing materials and products already manufactured.
To satisfy this requirement, the CBF project team investigated many different materials that could be used as the exterior wall finish of the building. Reclaimed “sinker cypress” was chosen because of its durability, longevity, beauty and history.
History of sinker cypress
Sinker cypress wood consists of cypress logs that have been submerged in rivers or swamps since the late 1800s. The logs were cut by axes or hand saws from 150- to 1500-year-old virgin forests during the “industrial cypress harvest” from 1880 to 1930. The fallen logs were then taken to the nearby rivers by oxen or horses to a neighboring riverside sawmill. During their trip down river, it was common for some of the logs to become waterlogged, or get stuck in a log jam, where they would sink to the bottom of the river. They have been preserved underwater since that time.
Today, the sunken logs are retrieved by divers, raised to the surface and shipped to a sawmill where they are cut into different lumber sizes and allowed to air dry. The required drying time is usually one year per one inch of thickness of the lumber. If a kiln is used to dry the lumber, then less time is needed for air-drying. Typical drying periods range from 1 to 2 years after the log is cut into lumber. This allows the wood to dry slowly and become more stable and resistant to warping and exterior elements.
Using sinker cypress for the Brock Environmental Center
The most important characteristics of sinker cypress are its durability and longevity. The wood typically lasts over 150 years without severe deterioration due to a natural preservative oil, cypresseine, which resists rot and insects. This made it a perfect choice for the exterior siding of the Brock Environmental Center.
The actual lumber profile being used in the Center is a ¾” thick x 5” wide board attached to a Forest Stewardship Council (FSC)-certified wood sub-frame over rigid insulation. The sinker cypress will have a 3-coat system of ultraviolet-resistant stain applied, which will also darken the natural color of the wood. This will help it match the design of the rest of the building.
In addition to using reclaimed sinker cypress, the Brock Environmental Center will be using fallen oak trees for benches, old school gym bleachers for interior trim and salvaged ceramic tile in restrooms, just to name a few of the resources being incorporated during construction. Learn more about how the Brock Environmental Center is reusing salvaged materials here.