NOFMA Tip Sheet: Color -- Staining Wood Flooring
The most important factor for coloring or staining wood flooring is customer expectation. What look does the customer want and expect to have? Once the look is established you must then determine, is it possible to provide the expected look? The next factor is what must be done to achieve the look.
Attaining a particular color or stain will almost always involve site finished rather than factory finished flooring. The most commonly used stains for site finishing flooring are oil based. These stains are user friendly, offering fairly simple application techniques as well as consistent and repeatable performance. Water-based stains and aniline dye stains are also available. Because application techniques for these stains are more difficult, good, repeatable results are hard to obtain. Only the experienced mechanic familiar with these specialty stain systems should use them.
The general application technique for oil stains is to apply stain in sections along the length of the flooring. Apply across reachable sections totally wetting the areas with stain. This is followed by uniformly wiping up all the excess stain from the surface of the flooring with rags. Repeat the process and overlap previously stained sections by 1 or 2 boards until the entire room or area has been stained.
• The overall color should be uniform and will include dark and light natural tonal variations of the wood.
• Because sanding scratches naturally absorb more stain color, scratches should be uniformly distributed and individual scratches highlighted by stain should not be prominent features on the casual glance from a standing position.
• A stain color difference, or halo, around the perimeter of the room is not acceptable.
• Leaving extra or excessive stain on the flooring to intensify color will affect finish performance negatively, often resulting in peeling finish.
• White, pastel, intense red, and very dark stains dry slowly, requiring extra dry time before over-coating.
• Splotchy, non-uniform coloration often results when staining species such as maple, beech, birch, pine, cherry, hickory/pecan and woods with similar non-porous characteristics.
• Any water dripped on the sanded floor will pop the grain and a water spot will result during staining-don't sweat on the floor!
• Stick with a single manufacturer if possible, follow their recommendations, and contact the manufacturer(s) for the special color or for questions on compatibility.
Wood flooring has to have a finish to protect it or it will be discolored from daily traffic and soiling. All finishing materials, even neutral colored finish, will impart some color to the flooring. The color and intensity of a neutral sealer or finish is very similar to freshly sanded wood that has been wetted. Some consumers want the light appearance of a freshly sanded floor. This is an unreasonable expectation in that any finish applied to freshly sanded flooring will change the appearance of the flooring by intensifying or darkening the color of the grain.
A uniform look from stain colors which show natural wood tones from light brown to medium brown are generally easiest to achieve and will likely complement any décor. For the contractor these colors translate into fewer steps and less time on the job. For the consumer these systems are less expensive than the special color systems.
On the other hand, specialty colors involve more steps, more time and more attention to detail. Also, the consumer often wants the particular look that is difficult to obtain, i.e. whiter or blacker. In order to get these more intense and special colors, the contractor must have a through working knowledge of the wood species and the finishing materials being used. Don't experiment on the 400 square foot beech floor to be stained cinnamon. After re-sanding 3 times and still not achieving the desired color, you will ultimately loose money-not to mention gain a stained reputation. Always prepare a sample, either on the floor or as a sample panel for the customer to view and approve. Be sure the sanding and finishing process is exactly the way you would prepare and finish the entire floor.
You should know that whites and intense reds generally have pigment particles that are quite large. Compared to the mid-colors, these large particles slow drying processes and are not absorbed easily into the wood particularly if very fine sanding has occurred. If there is too much stain residue left on the floor, the top coat will stick to the residue and not the underlying wood fibers. In addition, if the stain is not completely dry before top coat application, the solvents will interfere with the coating properly adhering. Peeling of the top coating will likely result.
The key aspect to successful staining is the sanding operation. In order for the stain to be consistent in color and intensity, sanding scratches must be uniform in depth, direction, and most important have a uniform frequency.
In order to achieve a uniform scratch pattern, practice good fundamental sanding techniques. The following laundry list addresses some but not all issues that can affect the stain and staining process.
• Keep all machinery in good working order, clean, and properly adjusted to avoid chatter, waves or irregular scratches.
• Clean the floor after each procedure.
• Pre-sand or repair problem boards before starting general sanding.
• Start and stop gradually, sand at an even pace, and don't "bump stop" the sander.
• For the first cut, sand on a slight angle in the flooring direction to flatten the floor, and help eliminate over-wood/under-wood and end joint variation.
• Never skip more than one intermediate grit i.e.- 30 to 40 (skip 36), 50 to 80 (skip 60), etc.
• Edge all possible areas not covered by drum sander.
• Don't pressure or allow edger to dig and create ruts and deep scratches.
• Blend edger scratch with drum scratch by hard plating, screening, and/or scraping and hand sanding.
• When screening/disc sanding, sand from edges toward center then from opposite edge to center to blend as sanding paper dulls.
• Hand scraping and hand sanding is not optional-certain areas will require them.
• After scraping, hand sand to create the desired scratch pattern.
• Moisture from placing a bare hand, knee, or foot on the sanded floor can create a print when stain is applied.
• With the softer wood species, be aware that dragging machines or toes can crush wood and leave a mark that will show when stain is applied.
• Stain the same day as the sanding is completed.
• Staining the second time can lighten the color of an oil stain because it is reactivated and diluted.
• Coarser grits which produce the deeper scratches can give darker overall color.
• The surface also looks rougher with the coarser sanding scratch.
• CLEAN and CLEAN and CLEAN.
Factory finished flooring can be a great option in providing some of the special looks. For instance, a dark red stained maple product is available. A similar color would be extremely difficult or impossible to obtain in a site finished floor. The customer can visit the distributor's showroom and select a particular product to meet the desired look. Sometimes this choice is the most efficient and least difficult particularly if the wood species and color selected are not compatible for coloring a site finished product. The purchased product should meet the customer's expectations. As a contractor, you should communicate with the customer to determine their expectations and fine tune the product as delivered to avoid problems.
Finally, communicate, communicate, communicate! For the extra special color show a sample using the actual procedures to get the color. The sample should be large enough to show natural color variations. Take a picture and/or save the sample. Figure in more time for the completed package. And above all, don't experiment on the 2,000-square-foot job- you just might not be around for the next magazine issue.