Field Support
Graham has always been dedicated to providing our customers with the support and training they need to understand everything about our products. We strive everyday to provide the best possible, product, but due to the nature of wood, some issues may arise that require a better understanding of what can be done to resolve those concerns. Below are some common subjects that may arise with your wood door and the support available from Graham.
Telegraphing and Warp
Telegraph or show-through is any distortion in the face veneer of a door caused by variation in thickness between the core materials and/or the vertical or horizontal edge bands. Warp is any distortion in the door itself and does not refer to the relationship of the door to the frame or jamb in which it is hung. The term “warp” shall include bow, cup or twist. Wood is a hygroscopic material. It constantly exchanges water vapor with the air, picking it up when atmospheric humidity is high, and giving it off when relative humidity is low. Since wood swells as it absorbs water, and shrinks as it releases water, both its moisture content and its dimensions are controlled by relative humidity of the surrounding air. Telegraphing and warpage are a reaction of the wood or wood products to the environment. There are many things that man has learned over the centuries about how to stabilize wood and wood products. The most important is a “magic” moisture level called “EquilibriumMoisture Content,” or E.M.C. The recommended moisture content for wood and wood products intended for interior use is 8% for approximately 75% of the continental United States. Data compiled by the USDA Forest Product Laboratory show that 7%-8% moisture content in wood is most suitably achieved at temperatures of 65-75 degrees Fahrenheit and relative humidity’s of 35% to 45%. In short, if the temperature and humidity levels of the environment into which the wood or wood products are placed are not controlled, warpage may result.
Relative Humidity & Moisture Content
It is the responsibility of the design professional to engineer the space in which fine woodwork (not to mention laminates, fabrics and wall coverings) is to be installed with humidity controls required to maintain the optimum humidity. (For additional data on moisture content and relative humidity refer to the USDA Forest Products Laboratory Wood handbook chapter 14, “Control of Moisture Content and Dimensional Changes”. The map shows the approximate average moisture content for interior use of finished woodwork recommended for general areas of the United States.
For more information contact your Graham Customer Service Professional.
USDA Forest Service, Agricultural Handbook No. 72
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