The first step to refinish a herringbone hardwood floor is to sand away the old finish and scratches. Traditional hardwood floors have all the wood slats running in the same direction. In these cases you can use a standard drum sander. However, drum sanders are designed to work with the wood grain. The pattern of a herringbone floor is not compatible with a drum sander, at least not for the novice. Use a square buff or random orbital machine for your job. Although these machines generally work slower than a drum sander, they can sand in any direction on the wood floor -- with or against the grain is not a problem for these machines, which makes them a perfect match for herringbone floors. Multiple sanding is done in several stages. Start with a coarse sand paper. Once the entire floor is sanded, move to medium then fine sand papers.
Sanding machines will only get so close to the edge of the wall. To get a clean, professional look, use a hand sander. Like the sander for the room at large, choose a random, orbital hand sander. Use a medium grit; even though it will take a little longer than using a coarse grit, you risk less chance of creating uneven swirl lines in the herringbone pattern if you put too much pressure on one side of the machine.
Cleaning the Floor
Before you begin and between each step of sanding, vacuum the floor with a utility vacuum. Make sure there are no small stones or other gritty items that can get stuck under your sander. A bit of grit lodged under your sander can gouge your herringbone pattern. When all the sanding is done, wipe the floor with a tack cloth soaked in mineral spirits.
Adding Stain and Urethane
Add wood stain to change the color of your wood floor, if desired. When the stain is dry you can add coats of urethane finish to complete the project. Stain is generally applied with a paint brush; urethane is usually put down with a lamb's wool applicator. Both are suggested to be put down in the direction of the wood grain, which is a problem for herringbone floors -- you will have to pick a direction and go with it. Spread both your stain and urethane finish in one direction, evenly over the floor. Some finishes require waiting as little as two hours between coats, while other may require waiting till the next day. Also, for proper coat adhesion, you may be required to sand and tack the floor between coats. Consult the manufacturer's directions for specific instructions regarding additional coats of urethane finish.
Wood floor refinishing involves dust and chemical vapors that can be harmful to your lungs and eyes. Wear appropriate personal protection equipment including goggles and dust masks. Work in a well ventilated area with the windows open or fan providing fresh air.