How To Refinish Hardwood Floors

Before floor refinishing with a sander, you should pull up the shoe base moulding along where the floor meets the wall.

• Pry up the moulding with a pry bar, using a piece of scrap wood to protect the baseboard.
• Number or otherwise label each piece as you remove it to make it easier to put it back after refinishing the floor. 

Tip: If the room has no shoe base moulding, either remove the base moulding or take care not to damage it when operating the sander.

Sanding eliminates scratches and stains from a hardwood floor, but may not be able to alleviate the deepest gouges or discolored patches of wood.

• Begin by using a drum sander or belt sander with the grain along the length of the boards.
• Always wear a dust mask, safety goggles and ear protection when using a drum sander.
• Work the drum sander back and forth over 3- to 4-foot lengths.
• Use overlapping strokes by at least 1/3 the belt width to remove scratches. 
• Start with coarse sandpaper of 36 to 40 grit, progress to a medium 60-grit paper and finish with a finer 100 grit. Do not skip the progression from coarse grades to finer grades. 
• Replace the abrasive belt after sanding about 250 square feet for most effective results.
• Sweep and vacuum the flooring to remove dust and debris between sanding with different grades of grit.

Tip: Practice using the drum sander on an old sheet of plywood until you’re comfortable operating it, and then use it on your wood flooring.

Use a floor edger or small orbital sander to sand corners, edges and small areas such as closet floors, bathrooms or stairs.

• An edger can be difficult to control, so practice your technique on scrap wood first.
• As with the drum sander, start with course-grit paper and then move to finer grades.
• If the flooring has small areas that even the edger cannot reach, use a scraper and some 80- and 100-grit sandpaper to remove the old finish by hand.

Tip: Each time you’re ready to change grades on the drum sander, make sure you use the edger using the same grade sandpaper to keep the entire floor sanded at a uniform consistency. For example, use the drum sander at 60-grade paper, then the edger with 60 grade, before changing to 80 grade.

Next, use a floor buffer fitted with a fine-grit screening pad to “screen-sand” the flooring. 

• This type of sanding will level minor unevenness left by the drum sander and edger as well as buff away sanding scratches. This fine-detail work can make your DIY project look more like a professional job.
• Be prepared for the buffer to swing to the right or left depending on how you position the handle, making broad arcs across the floor to get a smooth surface.

Thoroughly sweep and vacuum the flooring and then follow up with a tack cloth to remove all the dust that you can. Dust and hairs can leave imperfections in the floor finish. 

If you want to change or improve the floor color, apply a stain. 

• Choose an interior wood stain based on the color you desire and the type of hardwood flooring you have. 
• Apply the stain with a foam applicator pad in the direction of the wood grain. 
• Work one manageable area at a time, such as four square feet.
• Many manufacturers recommend removing excess stain as you go, usually a few minutes after application.
• Use clean cotton cloths or paper towels to remove excess stain. Some finishers prefer wiping the floor with a cotton cloth wrapped around a dry applicator pad.
• Allow the stain to dry according to directions before applying the finish.

Tip: If you choose not to stain, apply a sanding sealer before the polyurethane finish.

Choose a protective coat of wood finish, weighing the following factors.

• Water-based polyurethane wood finishes or lacquers dry quickly, which can pose challenges during application.
• Oil-based polyurethane wood finish dries more slowly, providing more time to ensure a smooth coat, but the fumes may require wearing a respirator during application. 
• Popular wood oils include Danish oil, teak oil, tung oil, cedar oil, ipe oil and mineral oil for wood.

Follow these steps when applying the finish.

• Apply the finish with a lamb’s wool applicator in smooth, even lines while avoiding drips.
• Consider three coats of oil-based finish or four coats of water-based finish.
• When each coat dries, sand the floor lightly with 220-grit paper or #000 steel wool. Many finishes take 24 hours to dry.
• Vacuum up the dust and apply the subsequent coat.
• When the finish is dry, reattach the shoe guard moulding.

Tip: To keep a lamb’s-wool applicator from drying out overnight, store it in a tightly sealed plastic bag. 

Consider these tips when refinishing hardwood floors. 

• Rent equipment such as drum sanders and edger sanders.
• Most drum and edger sanders have built in vacuums and dust bag systems to reduce dust emissions.
• After sanding, fill in holes in the floor with wood putty or wood filler.
• Be sure to work in well-ventilated rooms when sanding or applying stain or finish.
• Spot test the stain or finish to see what it looks like on the floor before applying a coat.
• Apply the stain or finish so your final steps are at the exit door and you don’t have to track through a wet floor.
• When returning the furniture to room, place felt pads on the feet to prevent them from scratching the floor. Avoid dragging furniture across the floor. 
• Flooring experts estimate that hardwood floors can be sanded for refinishing up to 10 times, depending on the thoroughness of the sanding and the level of wear and tear on the floor. Situations differ, but you may not be able to refinish your hardwood floor more than 10 times.

Safety Tip: Store and dispose of oil-soaked rags properly. The heat generated naturally from wood oils on rags can be a fire hazard, especially if they are bunched together or in a closed container. Hang the rags outside, away from any structures, and allow them to dry thoroughly before disposing of them.