DWC Home | Magazine | Back Issues | April 2005 | Design Perspectives

More Articles by Karla J. Nielson  More Design Perspectives

DESIGNPERSPECTIVES:
Warm Woods
For interior design, wood products grow in popularity.

by Karla Nielson, ASID Allied Member,WCAA

At the window, wood and wood-like treatments are at an all-time high in terms of popularity and functionality. Wood is a topic worth understanding, as the more we know, the better we can help our clients make the right decisions. Let’s begin with a quick lesson in wood.

Most wood window coverings products are harvested from wood cut by one of three methods: plain (straight grain), quarter (vaulted grain) or rotary slicing (irregular vaulting). Wood from broad-leaved trees that generally lose their leaves in winter are called hardwoods, and woods from needle bearing, coniferous trees are called softwoods. Generally, hardwood is used for furniture and high-grade flooring. Wood for shutters and wood blinds is often softwood, which can be worked more easily and is lighter in weight than hardwood. However, many shutters today are made of hardwoods and engineered wood.

Engineered wood typically is a combination of engineered polymers and real hardwood bonded together by various, often proprietary, processes. They are an economical, environmentally sound alternative to solid wood and usually come with a performance guarantee that ensures the products will not fade, yellow, warp or bow under any condition.

Wood is ideal as permanent or semi-permanent window coverings because of its impressive qualities. Wood is strong, hard, stiff and dense. Strength does vary according to the type of wood—some woods are stronger in some areas than others. Wood generally has compression strength and can be bent under heated, moist conditions, although different woods rank stronger in compression and weaker in bending strength or vise versa. Thus, certain woods are better suited to some applications than others, so specific woods used for manufactured products have the right combination of strengths and features.

Freshly cut wood contains water—from one-third to more than one-half of the total weight—and must be seasoned before manufacturing either by air-drying (several months) or kiln-drying (a few days). The wood must be carefully stacked to prevent warping, and the rate of drying must be carefully controlled so that the wood doesn’t change in shape during the process. Seasoned wood resists decay and is much lighter and, therefore, less expensive to ship.

Wood is durable. If not attacked by living organisms, it will last for hundreds or even thousands of years. The most important of the organisms attacking wood are the fungi that cause so-called dry rot, although it actually occurs only when the wood is damp. A number of woods are comparatively resistant to termites including redwood, black walnut, mahogany and several types of cedar. In most of these cases, the woods are aromatic and the resistance probably is due to the resins and similar chemicals they contain.

Wood may be preserved by protecting it chemically against deterioration via impregnation with creosote or zinc chloride or a number of newer chemicals including copper compounds. Wood can be protected against weathering by suitable surface coatings applied by brushing, spraying or dipping.

Certain new products consist essentially of a mixture of wood with certain chemicals; such a mixture will have mechanical properties similar to those of wood, but will be stronger and more resistant chemically. The most important methods of making these mixtures consist of impregnating the wood with certain chemicals, such as a mixture of phenol and formaldehyde, and then heating the impregnated wood so that the chemicals react within the cells of the wood to form a plastic.

Wood treated with such resins is known as impreg. It has great resistance to decay and to insect and borer attack. Its specific gravity is increased, but its strength is increased only slightly, if at all.

A different product, called compreg, is made by compressing the impregnated wood in a hydraulic press at pressures of about 70 kg/sq. cm. (about 1,000 lb/sq. in.) while the chemical reaction which forms the plastic is progressing. Such compressed impregnated wood may have a specific gravity up to about 1.35. The hardness is many times as great as that of the original wood, and the strength is somewhat greater, although the toughness may be less.

SHUTTERS AND BLINDS
An understanding of how wood must be seasoned, stacked and carefully treated, explains why some wood shutters warp slightly after installation. In very moist climates, wood may indeed swell and warp. However, quality wood shutters, properly treated and prepared, will last for generations. As such, they often are sold as “furniture for the windows.” There are some installations for which vinyl or composite shutters and blinds will be valuable, as well.

Shutters are typically an end-product use in that they are handsome and finished without any added fabric or ornamentation. They most often are a stand-alone architectural look.
Wood and wood-like blinds are a popular choice for several reasons. Like shutters, two-inch wood blinds are stained, treated or, most often, painted for ease of cleaning and cleanliness of appearance. Wood blinds have some advantages in that they are generally less costly than shutters, can stack more or less out of the way and when opened do not have vertical stile impediments to the view.

WOOD-LIKE MATERIAL—GRASSES
The families of grasses that are used for woven products and are similar to wood include grasscloth woven textiles (and their polyester faux partners) and the bamboo genre, which is categorized with wood, but is technically a grass.

Bamboo is a common name for 60 genera and 1,000 species in the grass or Poaceae family, a family of monocots—the perennial, woody, usually shrubby or treelike plants of the grass family. The different species of bamboo range in height from the smallest at six inches to the giant variety at 130 feet.

Bamboo has more than 1,500 documented uses and can be found in North America, South America, Africa, Australia and southern Asia with the highest diversity in China. In America, bamboo products are used for flooring, furniture and accessories, and for blinds or shades and most recently as a shutter material.

A highly renewable resource, bamboo is fast-growing; depending on the species, the stems, called culms, can grow up to a foot a day with a lifecycle that is highly productive. Thus bamboo is emerging as a highly favored and desirable material for the environmentally aware future of interior design products.

Although young bamboo can be harvested and eaten as vegetables, in four years time the culms, or hollow internodes, will become more woody and composed less of water.

WOVEN WOOD PRODUCTS
Woven wood products have increased dramatically in popularity over the last several years. Woven wood products, whether of wood, bamboo, grasses or polymers, offer the consumer the warmth of wood tones, a depth of color palette and the richness and variations in the surface. In some products these characteristics offer a naturalness that is deeply pleasing and easy to live with.

Woven wood products can filter daylight, assuring daytime privacy and are often sheer in appearance—even gossamer-like and mystically intriguing. They can be lined for nighttime privacy. Most treatments operate as cloth shades and combined with a general style direction of Oriental influence, which is very mainstream today, woven wood products are a natural choice for many contemporary interiors.

Karla J. Nielson, Allied ASID, WCAA, is assistant professor of design at Brigham Young University. She is a practicing interior designer and has authored several books including Window Treatments and Understanding Fabrics. Nielson is a regular correspondent for Draperies & Window Coverings addressing the areas of fashion, education and merchandising.