Treesearch

Wood finishes (paint, varnish, and stain, for example) give a desired appearance, protect wood surfaces, and provide a cleanable surface. Many people consider appearance most important when choosing finishes for wood products. However, from a technical aspect, protection—from water, sunlight, and weathering—is most important for wood used outdoors. For wood indoors, appearance and a cleanable surface are generally most important. When selecting a finish, one should consider appearance, protection, cleanability, how properties of wood affect finish application, and how long it will likely...

In North America, most housing and commercial structures built prior to the 20th century used wood as the major structural material. The abundant wood resource formed the basic structure for most houses, commercial buildings, bridges, and utility poles. Today, houses and many light commercial and industrial buildings are made using modern wood structural materials. Recently, there has been increased interest in using wood for various types of transportation structures, including highway bridges. In this chapter, the features of various types of building systems are described. Emphasis is...

Fire safety is an important concern in all types of construction. The high level of national concern for fire safety is reflected in limitations and design requirements in building codes. These code requirements and related fire performance data are discussed in the context of fire safety design and evaluation in the initial section of this chapter. Because basic data on fire behavior of wood products are used to evaluate fire safety for wood construction, the second major section of this chapter provides additional information on fire behavior and fire performance characteristics of wood...

Many specialty treatments can be applied to wood to improve its performance. Treatments addressed in this chapter are those that make permanent changes in the shape of a wood product or improve properties, such as hardness, toughness, moisture resistance, dimensional stability, decay resistance, and mechanical or machining properties, through combinations with nonwood resources such as resins, polyethylene glycol (PEG), and acrylates.

Insects and other pests can travel between countries in pallets and other wood packaging materials through international trade. Because these pests can cause significant ecological damage, their invasion into non-native countries is undesirable. Heat sterilization is currently the most practical and environmentally friendly treatment to kill pests in solid wood materials and prevent their transfer between continents and regions. Consequently, regulations requiring heat sterilization are becoming more common. Two important questions should be considered in heat sterilizing solid wood...

Under proper conditions, wood will give centuries of service. However, when wood is exposed to conditions that allow the growth of wood-degrading organisms, protection must be provided during processing, merchandising, and use. The organisms that can degrade wood are principally fungi, insects, bacteria, and marine borers. Molds, most sapwood stains, and decay are caused by fungi, which are microscopic, thread-like microorganisms that must have organic material to live. For some of them, wood offers the required food supply. The growth of fungi depends on suitably mild temperatures,...

Wood products can be protected from the attack of decay fungi, harmful insects, or marine borers by applying chemical preservatives. Preservative treatments greatly increase the life of wood structures, thus reducing replacement costs and allowing more efficient use of forest resources. The degree of protection achieved depends on the preservative used and the proper penetration and retention of the chemicals. Some preservatives are more effective than others, and some are more adaptable to certain use requirements. To obtain long-term effectiveness, adequate penetration and retention are...

Structural analysis mathematically models the physical forces, deformations, and stresses acting within a system. Structural analysis may generally apply to the construction of aircraft, bridges, buildings, furniture, pallets and shipping containers, sculpture, sporting equipment, and tools. In other words, structural analysis is useful in nearly every aspect of wood engineering. The ability to model deformations and stresses under load naturally lends itself to efficient design and, ultimately, effective use of materials.

A large portion of wood products made today are glued, or bonded, together. This is because bonding allows wood to be used in ways that would be impossible otherwise. We take wooden sheet materials, such as plywood, for granted, but they perform far better in some ways, and are far less expensive, than solid wood alternatives. Large structural pieces, such as the glulam skeletons in many buildings, would be impractical without adhesives. Everyday items such as wooden chairs would be extremely difficult to build without adhesives. In short, bonding wood products increases their value. This...

Because wood properties vary among species, between trees of the same species, and between pieces from the same tree, solid wood cannot match reconstituted wood in the range of properties that can be controlled. Wood with localized defects (such as knots) can often be utilized effectively in wood-based composites. When wood with defects is reduced to wood elements, the influence of these characteristics in the manufactured product is reduced. To reinforce sustainable harvesting efforts, wood derived from small-diameter timber, forest residues, or exotic and invasive species may also be...