By Eric Kurtz, LEED® Green Associate, Bostik’s Market Manager for Hardwood Installation Systems
The hardwood industry has changed quickly over the last decade. The flooring itself has trended toward wider plank, engineered is now more common than solid, prefinished flooring has grown in popularity as well as capability, click and floating floors are on the rise, and there are more and more types of flooring emulating the look of real hardwood.
Installation systems have evolved as well. All-in-one adhesives with moisture vapor and sound reduction properties are now common. Zero VOC formulations are in nearly every major adhesive manufacturer’s portfolio. New adhesive technologies, such as Bostik’s AXIOS® Tri-Linking technology found in GreenForce® and Ultra-Set® SingleStep2™ are raising the bar in performance, not only in moisture protection, sound abatement, and zero VOC’s, but also workability, ease of clean even after cure, and ridge retention (to prevent hollow spots).
With this degree of change comes uncertainty. Understanding these new products and systems is critical to avoid installation issues, make customers happy, and extract the value for the contractor.
AVOIDING INSTALLATION ISSUES
All-in-one adhesives like Bostik’s BEST®, Vapor-Lock™, GreenForce®, and Ultra-Set® SingleStep2™ are amazing, time-saving installation systems that offer a lifetime warranty for unlimited moisture vapor protection with no concrete moisture testing required – the concrete simply must be dry to the touch. Vapor-Lock™ and Ultra-Set® SingleStep2™ go even further in offering sound abatement equivalent to ¼” cork or rubber underlayments. Understanding the requirements of the specific products is the key to getting the advanced performance desired. For example, Bostik’s BEST® offers unlimited moisture vapor protection to engineered hardwood, which is more dimensionally stable than solid hardwood. Vapor-Lock™ offers a higher level of protection, so it offers unlimited moisture vapor protection for engineered and solid hardwood, but it does have a 15 lb moisture vapor emission rate or 87% RH limit on bamboo, which as a category is least dimensionally stable. There are no flooring type limitations on GreenForce® or Ultra-Set® SingleStep2™, and there are no board width or length restrictions on any Bostik adhesive.
The ability of all-in-one adhesive and moisture vapor membranes to achieve this exceptional level of performance requires that they form a continuous membrane to be effective. Voids in the membrane could allow significant amounts of moisture through from the subfloor to the hardwood and result in failures. As a result, coverage rates must never be stretched.
One of the most significant causes of voids in all-in-one membranes is the condition of the subfloor. Nothing is more important than proper subfloor prep. Subfloors must be flat per NWFA standards to within 3/16 inch in 10 feet, and excessive roughness of the surface can influence the coverage rate. Self-leveling underlayments, such as Bostik’s SL-100™,
SL-150™, SL-175™, and SL-200™, are a very easy and effective way to achieve a flat subfloor. Be very careful in selecting the self-leveler though. Many products on the market have moisture limitations and may break down underneath the flooring over time as they are exposed to moisture vapor, especially in applications where unlimited moisture vapor protection is desired. The Bostik self-levelers listed above have no moisture vapor limitations and will support unlimited moisture vapor protection systems.
To reduce the inherent risks of not being able to see that proper coverage has been achieved, many installers prefer two-step systems comprised of a moisture vapor barrier coating and an adhesive. The two most common moisture vapor barrier coatings are epoxies, such as Bostik’s Slab-Cote™ or D-250™, or urethane membranes, such as Bostik’s MVP4®. The advantage of a two-step process is that visual inspection is possible to identify and remedy any voids because the moisture barrier is applied prior to bonding the flooring. Photographs may also be taken before the flooring is installed. The disadvantages of the two-step process are that it increases the project timeline, requires additional installation labor and materials, and the flooring can’t be installed until the coating cures – typically requiring 24 hours and a return trip to the job site for the installer.
Moisture vapor moving through slabs is one of the most common causes of failure of hardwood flooring installations on concrete. All-in-one products are an excellent solution if the slab is properly prepared, enough adhesive is applied, the moisture vapor emission rate (or RH) does not exceed the limits of the all-in-one being used, and installation is performed carefully to manufacturer specifications.
ENHANCING VALUE AND CUSTOMER SATISFACTION
First and foremost, the customer will be unhappy if there is an issue with their flooring, whether from moisture damage, hollow spots, gapping, finish, or other aesthetic problems. Simply avoiding problems will not make the customer happy. They need to know that the value they are getting in their new floor is exceptional – that they are getting something special.
Hardwood increases home values better than any other flooring type. In a recent survey, hardwood flooring was revealed to have the same level of emotional connection as fine furniture. Imitation hardwood such as vinyl and tile are getting better at mimicking the appearance of hardwood, but they will never have the character or feel that real hardwood provides. They are not made from natural, renewable materials. They will never match the warmth, comfort, sound, or smell of hardwood flooring, making it a truly unique experiential connection.
The installation system is also critical to the value of a hardwood installation. While floating floors install quickly, they will never equal the durability, sound and under foot feel of a solid, bonded floor. While many of the floating floor underlayments prevent some sound transmission through a floor, they do little for the sound of footsteps within the room. They cannot provide the solid feel under foot as the flooring deflects with each step, increasing the potential for creaking or popping, and undermining the experience of even the most well-designed interior space.