Mastery in Finishing

Photos courtesy of NWFA

Wood floors are known for their timeless beauty and durability, but it’s the finish that truly enhances the natural look and character of the wood. Whether it’s stain, sealer, penetrating oil, hardwax oil, or a protective topcoat, every product has its place and plays a crucial role in determining the final outcome.

Mastery in finishing encompasses far more than just completing the task of laying down a coat of finish; it’s an art form that embodies a holistic approach to craftsmanship, characterized by meticulous attention to the details required to produce a product worthy of being considered “perfect.”

If you are reading this and expect the recipe for perfection, I can tell you there is no such thing. Wood floors are to be walked-on, lived-on, worn-in, even scratched and dented. And they will last for centuries. Wood floors are hand-crafted, and finishes are hand-applied onto floors that are imperfect by nature, in environments that are far from sterile.

That said, finishing a wood floor is an art and a skill that only comes with understanding the many complexities involved in the entire process fully. The following highlights some of those complexities and offers a recipe for working toward achieving a flawless coat of finish.

Secure the Jobsite: Be cognizant of extreme jobsite conditions and make necessary adjustments to create an environment conducive to the proper application of the finish. Regardless of how many situations will adversely affect the final coat of finish, if you don’t take everything into account, the finish will not perform as intended. This includes keeping homeowners and other trades away, which alleviates unnecessary foot-traffic from the workspace; assessing the HVAC system; addressing any water leaks; identifying or testing for any sort of contaminants. In addition, be mindful of airborne debris. Inspect weather stripping at exterior doors and windows. Large windows that are adjacent to the floor could introduce heat to the environment. Lastly, hang signs at all entrances and do not allow traffic onto the floor.

The Sanding Process: The quality of the sand job will dictate how the finish looks and performs. Before deciding how the floor should be sanded, you need to determine what your “endgame” is. The “endgame” is defined by the finish that will be used on the floor. If the finish you’re using indicates the final cut needs to be a 120-grit abrasive, this is your “endgame.” The floor itself will dictate where you need to start, and what process should be followed to get to that endgame. NWFA Sand and Finish Guidelines have detailed instructions on the proper sanding process and sequence.

Tampico brush

Tampico Brush: After the floor has been sanded, the use of a Tampico brush on the buffer will loosen and remove dust from the open grain within the wood, and result in a much cleaner floor surface. The Tampico brush also minimizes grain raise, which can ultimately result in a smoother coat.

 

Vacuum all dust from the jobsite.

Vacuuming: After sanding is complete, vacuum all dust from the baseboards, windows, sills, doors, and door frames to avoid dust/debris from falling onto the floor. Clean from the highest surface to the lowest, in that order. Use a cloth and/or a duster where appropriate. After every surface has been thoroughly vacuumed or wiped down, the floor should be vacuumed. Vacuum the perimeter of the floor, and any in-floor vents, then follow up by using a wand with a clean vacuum head in the direction of the floorboards to remove all dust from the surface and between any cracks. There are two primary types of professional vacuum wand heads used on wood flooring: felt vacuum heads are more efficient in extracting dust from the surface and from cracks and crevices. This is the best choice for final cleaning prior to finish application or between coats. The bristle-head vacuum brush attachments are good for extracting larger debris and loosening dust from open grain within the wood.

Dry tack

Dry Tack: Dry tack the floor thoroughly after vacuuming to remove all the fine dust particles from the floor surface, or in between coats. Microfiber mops are usually made of synthetic fibers, typically polyester, polyamide, nylon, or a composite of any of the three. These small fibers rub together creating a micro-static charge. This charge assists in physically pulling fine wood dust particles into the cloth from the floor surface. When the mop is fully loaded with dust, simply vacuum it to remove the dust (this recharges the static on your mop as well).

Inspect the Floor: Inspect the floor carefully for all sanding imperfections from different angles. Direct light sources or lamps will highlight imperfections and may be used as a tool to evaluate imperfections. (This is a professional’s tool, not a homeowner’s tool trying to make a determination of acceptability.) Repair all imperfections as necessary using a scraper and/or sandpaper, and finish by hand rubbing with an appropriate abrasive pad. If the result is not satisfactory, the sanding steps must be repeated.

Staging area

Staging Area: Set up a staging area to place all tools, finishes, supplies, and other items necessary for the job. This staging area should be inside the jobsite, directly accessible from the floor being coated. This step minimizes unnecessary trips to and from your work vehicle, which could introduce potential contamination to the floor. It also allows all of the materials being used to acclimate to the interior temperature of the jobsite.

HVAC Systems: The heating, ventilation, and air conditioning (HVAC) systems need to be operating and maintained at “normal living conditions.” Extreme temperatures (above 80°F or below 60°F) or humidity levels (above 50 percent or below 30 percent) can affect the drying and curing process of the finishes.

Airflow: Airflow is important to the drying process of the finish. Stagnant air does not allow the finish to dry properly, however, during application, air movement can cause finishes to dry prematurely, which can negatively affect the end result. Air movement can also force airborne particles into the drying finish film. When applicable, set the thermostat to come on about an hour after the finish has been applied. Do not turn the HVAC completely off unless it’s required due to a finish being applied or for safety purposes. Turn all ceiling fans off during the finish application.

Applicators

Application Tools: The applicator you use should be determined by the finish manufacturer’s specific instructions. Understand which type is recommended and how to use it properly.

  • Applicators for film-forming finishes include wood blocks, t-bars, rollers, and cut-in pads. The fibers, foam, and adhesives used in some of these applicators may break down and degrade with exposure to some of the more-aggressive solvent finishes such as universal alcohol sealers, acid-cured or moisture-cured urethanes, or high solvent acetone, MEK, or toluene. The nap of the applicator or roller sleeve will dictate the coverage-rate of the finish being applied. These applicators may shed. It is crucial to remove the loose fibers from the applicator or roller sleeves prior to application of any finish.
  • Brushes may be made from natural bristles, nylon bristles, foam, or other synthetic materials.
  • Non-abrasive buffing pads are commonly used for stains, natural oils, or hardwax oils. A secondary polishing pad, clean carpet remnant, or similar pad is normally used for burnishing and removal of the stains or oils. Some manufacturers then suggest the use of terry cloth towels for that final step.

Do not use an old applicator for one type or sheen of finish that was previously used on another. A contaminated applicator can cause streaky finish or undesirable results. The cost of applicator sleeves and refills is minimal compared to recoating or resanding an entire job.

Choose the Right Finish: Select the appropriate finish based on your customer’s desired look, durability needs, and lifestyle. Read and understand the mixing and application instructions. Most manufacturers recommend using products within a designated system, and from the same manufacturer. Before using different manufacturers for stain and finish products, check with the manufacturers
for compatibility.

Prepare the Finish: Identify how many square feet you need to coat, and secure enough product to do the job. When calculating how much finish you will need for the job, mix slightly more than you think you will need in case you happen to lose product during application (vents, cracks, holes, etc.).

Batch together the appropriate amount of product to complete the entire job (based on the recommended coverage rates). Batching ensures consistency in what you’re laying down, in case there is any variance from one container to the next. Mix in a clean tray, bucket, or container. Mix the finish exactly as recommended by the manufacturer. Some finishes need to be stirred, some need to be rocked gently, and some need to be shaken vigorously.

Mastery in finishing encompasses far more than just completing the task of laying down a coat of finish; it’s an artform that embodies a holistic approach to craftsmanship, characterized by meticulous attention to the details required to produce a product worthy of being considered “perfect.”

Debris in finish

Prepare Yourself: You are the only entity that stands between the finish and the wood. If you’re sloppy, dusty, hairy, or messy, the finished product will reflect your demeanor. Vacuum your clothes to remove all dust, hair, or lint. Clean your shoes. Better yet, have a pair of shoes which are only used for coating floors. If you have hair, contain it. It may require putting long hair in a ponytail or wearing a hair net. Stay clean-shaven, or maintain your beard/mustache to avoid dropped hair in the final coat. Even if removing it from the final coat is a simple fix.

Application of the Finish: Map out the entire jobsite to determine where to begin and where the exit will be during application. Always use the direction, doorways, and primary focal points with the wood floor to determine cut-off points.

Understand how quickly the product sets-up based on the solvents in the finish and the environment they’re being applied in. Some finishes set up very quickly, such as waterborne finishes in dry climates, moisture-cure finishes in humid climates, and alcohol-based finishes in any climate. Other finishes remain open for long periods of time, allowing for more flexibility in the application process.

Work Methodically: Begin the application along one edge of the room in the direction of the flooring and work your way toward the exit, applying the finish in smooth, overlapping strokes. Cut in at the walls. Remove excess from the applicator and apply liberally, with smooth, even strokes along the grain. Work in a path narrow enough to maintain a wet edge, and feather strokes back into the area just covered. Do not overwork the finish. Finish applied too thin or too thick can negatively affect the intended appearance and performance. If you run into a scenario where you’re running out of finish, find a good stopping point, mix more product, and complete the job. If the finish has begun to dry or skin over, wait until the entire floor has dried before attempting to touch up missed spots or holidays. Rushing the drying process can lead to imperfections in the finished product.

Sand Between Coats: Depending on the type of finish you’re using, you may need to lightly sand the surface between coats to ensure adhesion and a smooth finish. Follow the manufacturer’s instructions regarding sanding between coats. The type and grit of the abrasive used for intercoat abrasion will affect how well the next coat sits on the floor. Many manufacturers have developed high-quality, fine-grit abrasives that effectively remove imperfections from the prior coat.

Final Inspection and Touch-Ups: Ensure each coat of finish is allowed to dry completely before applying the next coat or allowing foot traffic on the floor. After the final coat has dried, inspect the floor for any imperfections such as bubbles, streaks, or uneven areas. Touch up any flaws carefully with additional coats of finish or by sanding and refinishing specific areas. Ensure the floor will be maintained with the correct product to preserve its beauty.

Mastering the art of wood floor finishing is an ongoing process that requires continuous learning and improvement. By embracing the principles of craftsmanship, remaining open to learn, staying up-to-date on the latest techniques and trends, experimenting with different finishes and application methods, seeking feedback from peers and experts, and continuously striving for excellence, you can achieve a final product worthy of being considered “perfect.”

Brett Miller is the vice president of technical standards, training, and certification for the National Wood Flooring Association in St. Louis. He can be reached at brett.miller@nwfa.org.

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