For even the most eye-catching wood flooring installations, hollow spots can be present in any installation. These hollow sounds can be normal occurrences, but often are accompanied by deflections, voids, and popping conditions which sometimes can necessitate costly replacements and renovations. In fact, hollow sounds cost the flooring industry millions of dollars every year. It’s crucial to understand what steps can be taken during an installation to prevent hollow spots, as well as the cost-effective tools and solutions available to silence them if they arise.
Studies show that the major cause of problems like hollow spots for wood flooring installations are voids between the flooring and the subfloor. The subfloor always must be properly flattened, clean, and dry before installation. A variety of solutions are available to achieve a properly prepared subfloor, including moisture barriers, primers, and self-leveling cementitious underlayments. Moisture barriers can enhance protection from subfloor moisture vastly, also while serving as a substrate consolidator and adhesion promoter. Certain primers can reduce the absorbency of substrates and improve adhesion between an underlayment and the substrate. Lastly, a high-performance self-leveling underlayment can offer a self-smoothing, rapid-setting, and flat substrate. For the ultimate peace of mind, identify complete systems that come from a single source, and can be used in combination with one another under a single warranty. This also will assist greatly should there be any postinstallation issues.
Proper adhesive application also plays a major role in the success of a wood flooring installation. Adhesive failing to have full contact with the flooring often results in gaps between the floor and subfloor. The use of an improper trowel, incorrect spread rate, inadequate coverage, or installing wood flooring over skinned over adhesive are all factors that can result in an inadequate bond and easily result in hollow spots. One way to avoid hollow spots proactively is to follow all manufacturer guidelines in its application.
Hollow spots in an installed wood floor are not always a legitimate concern. Where vertical deflection accompanies a hollow sound, it needs to be addressed, otherwise it may just be a normal component of the installation. When it becomes a concern, there are two kinds of approaches to remedy the concern. The traditional option would be to remove and replace the damaged sections. Huge swaths of the floor may need to be redone to ensure no hollow areas are missed. This route can be destructive, messy, and costly, and may necessitate the use of pry bars and hammers. A fresh layer of adhesive and new wood planks would then need to be installed, along with a new finish for the wood flooring. Often the finish requires several coats to achieve an evenly matched color. This approach is the worst-case scenario for homeowners and may entail days or weeks of repair, along with substantial costs. Essentially, time and money.
Fortunately, there is a second option available – injectable adhesives. This innovative and cost-effective option provides everything you need to fill hollow spots by injecting a repair adhesive directly through the existing floor. Wood floor repair kits are functional and easy to use for both the professional flooring installer and the DIYer. The process is four simple steps: drill two or more holes (between boards, or at board joints), draw adhesive into the syringe, inject the adhesive, and fill the holes with dowels (or a toothpick).
A properly injected repair will eliminate any vertical deflection, but may not completely remove the hollow sounds. The included drill bit and applicator tips are small and discreet in diameter, meaning the only destruction involved is in the form of small holes that are hidden easily with dowels or putty. There’s no set up time or weighing down of the floor required, and the floor can be walked on immediately after the injection. These kits feature reusable tools and easy-to-clean adhesive technology, requiring only a damp cloth or mineral spirits for clean-up. Adhesive replenishment containers are available for those installations with widespread hollow spots.
No matter how much care is given to installation planning, subfloor preparation, and adhesive application, hollow spots can be a concern that you should be ready to address. With repair injection kits, the popping, cracking, and echoing of a hollow spot no longer needs to be cause for dread. A repair kit delivers peace of mind at an exceptionally low cost when compared to an expansive wood floor replacement, making it a must-have, fail-safe solution for both installers and homeowners.
Nick Mizzone is the marketing manager for Sika Corporation in Lyndhurst, New Jersey. He can be reached at mizzone.nick@us.sika.com.
