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Composites made from wood, other biomass resources and polymers have existed for a long time but the nature of many of these composites has changed in recent decades. Wood-thermoset composites date to the early 1900s. "Thermosets" or thermosetting polymers are plastics that, once cured, cannot be remelted by heating. These include cured resins such as epoxies and phenolics, plastics used as wood adhesives with which the forest products industry is traditionally most familiar (see Chapter 9). For example, an early commercial composite marketed under the trade name Bakelite was composed of...

One of the greatest assets of cellulosic resources is their compatibility with nature, including their combustibility and degradability which allow for constant turnover and regeneration of these natural resources. A fundamental understanding of these properties and possible methods for controlling them is essential for protection and better utilization of these resources.

Wood exposed outdoors can last for centuries. What kind of wood you choose and how you protect it can make a big difference in how long the wood lasts. Two conditions influence the service life of outdoor wood: weathering and decay.

Removing paint and other film-forming finishes is a time consuming and often difficult process. In some cases, finishes need to be removed prior to repainting; for example, if the old surface is covered with severely peeled or blistered paint or if excessive paint buildup has caused cross-grain cracking. You must also remove the finish before applying a penetrating stain or water-repellent finish to a previously painted or stained (solid color) surface.

You have decided to put wood siding on your new house. Several questions are probably going through your mind: “What’s the best type of wood?” “Should I use paint or stain?” “Should I apply the finish before or after I install the siding?”

Dipping new siding or decking pieces before installation is faster than finishing after installation, and it gets finish on the backside and ends of the pieces, thereby extending their service life. This method is appropriate for any penetrating finish, such as waterrepellent preservatives or semitransparent stains. It may also be used to pre-treat siding with water-repellent preservative before painting, which can greatly extend the service life of the paint.

The “Madison formula” was developed at the Forest Products Laboratory around 1950 as a simple linseed-oil-based finish that could be made from readily available components. It was one of the first formulations of its type—a penetrating finish that eliminated the problems with cracking and peeling commonly found with the oil-based paints available at that time. The finish could be made with pigment to give a semitransparent stain or without pigment to give a water repellent preservative (WRP). For more information, see the original 1979 document, “Forest Products Laboratory Natural Finish.”

If you’ve ever admired an old, unpainted barn that has survived 100 years or more of weather, it’s easy to wonder why you should use a finish on your home. However, the cracks, fissures, and air spaces that give weathered barn siding its character wouldn’t be acceptable on most houses. For a discussion of weathering and decay see the FinishLine “Outdoor Furniture, Artwork, Fences, and Play Equipment.”

Wood decks have become an important part of residential construction. Wood decks can add versatile living space to a home and, with minimal maintenance, provide decades of use. However, wood decks are exposed to high levels of stress from severe weather conditions that shrink and swell the wood. Without proper maintenance, wood decks can develop problems such as checks and cracks, raised grain, and mildew, thus increasing the risk of decay and insect attack. Because of these risks, lumber used in decks is usually pressure treated with a preservative, or the lumber used is a naturally...

Many wood shakes and shingles have been replaced by composition or asphalt-based shingles. Nevertheless, wood shakes and shingles are still widely used on commercial structures and residential houses.