How to Finish on Site
Many builders prefer to finish hardwood flooring, staircases and paneling on site. Attaining a high-quality finish on site is possible, but it requires planning, time and careful attention to detail. That deep, glossy, finished look takes more than the standard three steps. The keys are repeated sanding, proper cleaning and multiple finish coats.
The following is a step-by-step guide to on site finishing: (Remember to follow all manufacturers recommended safety procedures.)
1. Let the wood adjust to the site.
2. Prepare the room. Keep dust to a minimum and maintain stable levels of temperature and humidity. Seal doorways with plastic film, and schedule other workers away from the job site. Mask off any surfaces you wish to protect.
3. Seal it. Solid hardwoods must be sealed on all sides because moisture can pass through the back, edges or ends as easily as from the exposed faces. To avoid shrinking, swelling and damage, you should precoat surfaces that you won't be able to reach after installation. For strip flooring, sealing the back is not generally done. However, sealing the back of wide plank is sometimes recommended to slow down moisture migration. Also, seal any ends and edges that abut a surface exposed to moisture, such as an exterior doorway or ceramic tile floor.
4. Smooth it. Sanding is critical to an attractive, durable finish. Items like paneling, stair rails or cabinetry usually require only light sanding. It’s recommended to sand hardwood flooring three times, with successively finer grades of paper. Sweep and vacuum the floor thoroughly after each sanding. Spot filling and other minor repairs should be taken care of before the final sanding pass.
5. Keep the surface clean. Smooth any flaws, then remove dust with a brush, broom and/or vacuum.
6. Stain it. Apply stain generously with a brush, rag or lambswool applicator according to manufacturer’s directions. Allow it to sink in, and remove the excess according to the manufacturer’s directions.
7. Seal and finish coats. When the stain is dry, apply the first finish coat and let it dry according to the manufacturer's directions. Drying or curing times will vary depending on type of finish you use. When it's dry, sand the surface with 150-to-180 grit paper, #1 steel wool, and/or an abrasive pad. Sweep and vacuum to remove the dust. For flooring, wrap a push broom with a lint-free cloth lightly dampened with water (never use too much water, only enough to remove the dust residue). Wipe the surface clean.
8. Sand, clean and coat again. The second or third finish coat will usually give you the desired result. Sanding between each coat of finish is generally required, check with the finish manufacturer.