For the standard finish, which can include coloring from neutral to light and medium staining, the customer can generally expect the following.
A smooth surface: the floor should be sanded flat with all mill marks removed and without over wood and under wood. Sander stops, edger digs, and dished grain should be avoided.
The finish itself should be uniform. A consistent gloss level should be present. Puddles, drips, and streaking should not be expected.
The flooring should be sanded only as much as necessary. Over-sanding reduces the life of the flooring and should be avoided.
Of course the corollary is that an occasional mistake of noted exclusions does not cause the floor to fail acceptance. This condition holds as long as the feature is not prominent when viewed from a standing position.
Now that expectations are set, let’s discuss the actual sanding and finishing processes.
Sweep the floor. Embedded grit and debris from other foot traffic must be removed. Vacuuming will likely miss some of this debris.
When sweeping identify and replace or repair problem boards. This includes boards with splits, shake, large broken knots, thin boards and those with bit ends, and other boards with unsound characters. Also, be sure to set all top nails and fasten any loose boards.
SandingThe purpose of the first sanding operation or the rough cut is to remove milling marks and flatten the floor. Today’s precision flooring machinery can produce very uniform flooring that requires less sanding than product from 25+ years ago. Normally a 50 or 60 grit sanding paper is sufficient for this purpose. Also, make the first pass on a 15 to 20 degree angle to the direction of the flooring. If the flooring is rough and these grits do not cut the floor efficiently, sand at an increased angle and/or use a coarser grit for the more aggressive cut. The angle cut prevents the sander from rounding and or highlighting board ends and can prevent telegraphing a sanding wave in the floor. With wide plank this is especially important since straight cutting will likely highlight the ends when stain is applied. After the angle cut it is necessary to straight cut the floor using the same grit as the angle cut.
Again set proper customer expectations, then give the customer a product that meets expectations, and everyone is pleased, you get paid and the customer is your advocate and a source of referral and future jobs.