Wood is a healthful choice for flooring provided that the subflooring, adhesives (if used), and finishes are carefully chosen to be healthful as well. In standard construction, unfinished wood floors are commonly nailed to a formaldehyde-emitting underlayment and then finished with solvent-based finishes that will outgas for many months. Noxious glues may also be used in the installation process.
There are several prefinished engineered flooring systems available that can be applied directly over concrete using a floating floor installation method. When considering a prefinished floor, order a dated sample, product literature, and an MSDS. Manufacturers will publish their underlayment requirements. Most require a vapor barrier of some sort between the underlayment and the flooring product and will state allowable maximum vapor emissions from the subfloor.
In our experience, most factory finishes have proven to be far more durable then any of the more benign finishes available for jobsite application. Furthermore, when a wood floor must be finished onsite the required sanding is a very dusty process, although dust levels can be reduced if you specify that a “dustless” process be used. For “dustless” sanding, a double-filter vacuum called a DCS unit is attached to the floor sander. It can contain up to 90 percent of the dust, making the process less dusty but by no means dustless.
All components of each wood floor application from underlayment to finish must be carefully analyzed. If you can look at both new and older installations that are similar to your proposed application, you will be able to carefully evaluate what the product smells like when it is new and how well it wears over time.
Wood Flooring International offers a complete line of both solid and prefinished engineered flooring using FSC certified wood. Their flooring is engineered to make very full use of the trees harvested. Their American Woods, Monteverde, Pacific Northwest, and Orchard Collections all meet Ei emissions standards (European standards set to limit formaldehyde emissions). These standards would permit up to an estimated 0.14 parts per million of formaldehyde for hardwoods. This is a significantly higher level than is permitted for wood-based products certified by GreenGuard, which sets a limit of 0.05 parts per million.
Prefinished Engineered Wood Flooring Systems
The following wood flooring systems meet stringent European emissions standards:
• Junckers: This is a solid wood engineered flooring system from Denmark that can be applied directly over concrete. It has a factory-applied UV-cured urethane finish and comes in a variety of wood species with trim pieces. Wood comes from a source with managed forestry practices.
• Kahrs: This is a solid wood engineered flooring system from Sweden with a factory-applied UV-cured multilayered acrylic finish. The wear layer is solid %- inch plain sawn. Available in eleven wood species.
• Rappgo: This is a Swedish system manufactured to meet German DIN emissions standards and containing a central layer of low-emissions plywood sandwiched between a top and bottom layer of solid wood. The product is distinctive in that the top wood has long plank length and the flooring holds up well in very dry conditions. It comes with a durable factory processed UV-cured acrylic finish that is fully cured by the time it reaches the jobsite.
Underlayment for Wood Flooring
Interior-grade plywood or particleboard, most commonly used for wood floor underlayment, should not be used anywhere in a healthy house. The following underlayments are acceptable:
• 1- or 2-inch tongue-and-groove wood or rough-sawn lumber laid diagonally.
• Exterior-grade plywood (CDX), if used for underlayment, should be stickered to air out onsite. When used for chemically sensitive persons, it should be sealed with an acceptable vapor-barrier sealant, as specified in this chapter.
