How to Refinish Fir Floors

Check to see if there is enough wood left to refinish your fir floors. If most of the nail heads are visible, the wood is too thin for refinishing, and will need to be replaced. If only a few nail heads are visible, these nails were likely not installed correctly, and there should be enough wood left to refinish the surface. If the wood is thin in only a few, high-trafficked areas, use reclaimed fir from a salvage facility to replace only these few planks before refinishing.

Clean the floor. Fir floors are soft, and the boards tend to settle over the years. This creates gaps between the boards that are larger than those found on other wood floors. Use a screwdriver or other pointed item to pry packed in dirt out from between the boards. Sweep or vacuum the fir to ensure the floor is clean.

Apply a wood filler to the entire surface using a trowel. Look for a filler that matches your fir floors as closely as possible. Spread the filler very lightly over the boards themselves, but pack it tightly into the gaps between each row. Wipe away excess material as much as possible.

Sand your floors. This will make the floor smooth and soft, and will also even out the joints of wood filler. Because fir is such a soft wood, it should be sanded by hand. Work in small areas at a time, sanding in the direction of the wood's grain. If you are experienced and comfortable using a power sander, this is another option. Power sanders should not be used on fir by inexperienced users.

Vacuum or sweep away sanding dust until the floor is clean. You may also want to wipe the floor with a cheese cloth or tack cloth to pick up fine dust.

Apply stains or seals as desired. Fir floors can vary greatly in color from board to board. Using a colored stain tends to emphasize these differences. A clear polyurethane coating can help protect the floor and prolong its life without drawing attention to dark spots and color variations. Use a paint brush or dry cloth to apply these coatings.