The impact of vinyl products on the building industry over the past 30 years has been nothing less than revolutionary. The introduction of vinyl siding in the 1960s and '70s ushered in a dramatic rethinking of the ways in which exterior building products are designed and manufactured. New materials meant choices — and important new opportunities.
Looking back, we can see this revolution actually comprised at least two phases. The initial phase saw the introduction and popularization of PVC as an innovative alternative to wood, metal or other siding choices.
The second phase saw this thinking expanded as PVC was applied to a wide range of other exterior products — window and door frames, gutters, shutters, fencing, decks and railing, to name just a few.
Today an important third phase has begun in the vinyl revo-lution. In many ways its long-term impact may be as significant as the introduction of PVC building products, since this phase involves the introduction of yet another type of building material: so-phis-ti-cated composites offering many of the best features of both wood and vinyl.
These re-markable new composites have the potential to reshape builders and homeowners' thinking in a way that hasn't been seen since vinyl's introduction more than 30 years ago. More important, this third wave of the vinyl revolution presents significant opportunities to those building industry professionals farsighted enough to be part of it.
WOOD COMPOSITES — SOME OF THE BASICS
In general terms, wood composites are produced using wood that has been ground into flour-like powder. This powder is mixed with a plastic that binds the wood together when melted. The mixed and melted composite substance is then extruded into components with various dimensions.
Wood composites offer many advantages over either traditional wood or all-vinyl components. Like pure PVC components, they will not split, splinter, rust, rot or corrode, and never need scraping, sanding or painting. Composites are also unaffected by termites or other wood-boring insects, and have added environmental appeal because they are manufactured using recycled wood scraps.
What's more, construction materials made of wood composites are stronger than vinyl alone. Yet wood composite components handle and cut like traditional wood counterparts and route better than vinyl, making it simple for crews trained in traditional wood construction to pick up on composite construction techniques quickly. Because of these advantages, wood composites are gaining widespread market acceptance in a very short time.
Moreover, a recent regulatory development helped to further speed the popularity of composites. Last year the Environmental Protection Agency announced it would ban most residential uses of wood products treated with copper arsenate, the most widely used chemical in the manufacture of pressure-treated lumber. The arsenic-laden pesticide has proven its ability to repel termites and other wood-boring insects, but it is suspected of being a cancer-causing chemical, and is now due to be phased out by 2004. This development added great urgency to the introduction and adoption of wood composites for outdoor construction applications such as fencing and railing.
CONTRACTORS: WHAT YOU SHOULD KNOW
As with any trend, contractors are wise to be careful about jumping on board before they understand the technology involved. There are important quality issues that should be understood and, while the contractor does not need to be an expert on composite manufacturing, he or she should understand what sets one type of product apart from another.
For example, material consistency is crucial to product performance, especially for use in exterior construction such as railing, an area in which we at Kroy Building Products have been pursuing the use of composites. It is essential to eliminate pockets of air within the product and to ensure a correct ratio of wood to plastic throughout the process.
At Kroy, we recognized the process of manufacturing composites was outside of the scope of our immediate manufacturing capability and technical proficiency, so we sought a partner that could provide technical knowledge and manufacturing guidance. Ultimately we selected Strandex Corp., based on its patented method of extrusion, which offers excellent material consistency and assures all the individual wood particles or fibers are encased in plastic. This is essential in order to protect the railing systems from rot, decay or termite damage.
Another important quality issue is the selection of raw components, including the wood type, the wood mesh or particle size, the type of plastic and the source of plastic. The various wood or plastic choices are dictated by three factors: the specific manufacturing process that is being used, the desired performance and cost of the end product. The processes and technology options for manufacturing composite materials are abundant and growing — a sign that this new type of exterior building product will continue to evolve and improve over the next few years.
The wood flour used in composite material is manufactured by recycling the waste from other woodworking processes such as furniture and cabinet making. The process can produce powder in a varying range of particle or mesh size, made from either softwood or hardwood.
In terms of the plastic binder materials, manufacturers use a broad range of substances, including high and low density polyethylene, PVC, polypropylene and polystyrene. Some manufacturers use virgin plastics, others use only recycled, while others use a combination of the two. In our case, we reviewed the possible use of recycled plastic, but concerns relating to availability and quality made virgin plastic a better choice. Ultimately, we settled on a composite that is composed of recycled pine wood flour and virgin PVC.
With the formulations and extrusion technology settled, the next question we faced was the product design itself. In making this decision, a further refinement helped us focus on our most promising new product — a series of railing designs that are enhanced by the addition of a pure vinyl capstock dubbed the Fair Bluff. The strong composite posts require no additional support — a significant advance over earlier systems that relied on wood posts that were simply oversleeved with vinyl.
John Forbis is a building materials industry consultant with JTF Enterprises in Lincoln, Neb. He retired last year as president and chief executive officer of Kroy Building Products Inc.