What Are the Differences Between Floor Finishes?

Penetrating Finishes

• Penetrating finishes, also called "penetrating seals," soak into the surface of the wood. Many such finishes are thinned with varnish, but natural oils also function as penetrating finishes. Natural oils don't harden the surface of the wood as much as penetrating finishes that contain resin . Penetrating finishes come with or without stain added, although clear finishes still slightly darken the floor as they soak in. Because penetrating finishes soak into the wood rather than staying on the surface, they provide a more natural look than surface finishes. Penetrating finishes leave the natural wood pores visible. These floor finishes come in low-gloss or satin varieties.

Surface Finishes

• Surface finishes, such as varnish, shellac and polyurethane, coat the surface of the floor with a hard protective layer. The user can paint multiple layers of surface finish on the floor to build up to a desired thickness. Because surface finishes stay on the surface of the wood, they can obscure the wood's natural texture. Most surface finishes are clear, but some come with pigment. Surface finishes tend to be more glossy than penetrating finishes, and they give wood a coated, glassy appearance.

Wear and Maintenance

• Surface finishes show scratches more easily than penetrating finishes. Penetrating finishes are part of the wood, so they don't flake or crack the way surface finishes might. Penetrating finishes also don't show wear in high-traffic areas as much as surface finishes. Surface finishes are also more difficult to patch than penetrating finishes. To fix scratches and dents in penetrating finishes, you can simply rub more finish onto the area with steel wool. It's also possible to add more penetrating finish to worn-out spots. To fix problems in surface finishes, you need to eventually refinish the entire floor.

Fillers and Sealers

• Fillers cover open pores in wood, giving floors a smooth surface. They are used underneath other finishes, and are an optional step when finishing floors. Some people like the open-grained appearance of oak and other woods, but others prefer the smooth surface created by fillers. Sealers prevent too much stain from soaking into the wood or prevent stain from bleeding into other clear finishes. Most modern stains and finishes do not require a separate sealer, but sealers will keep knots in wood from bleeding into the finish. They also help extra-absorbent parts of the wood, like roughly cut edges, from absorbing too much stain and becoming darker than the rest of the wood.