Hardwood floor finishes protect hardwood floor from wear, tear, water, stains, scratches, and other substances that might make it look faded with the reasonable usage. From our experience and common sense we can say that finishes are very important because only protected hardwood floor can maintain its beauty and long-lasting performance. All finishes are nontoxic when fully cured and once the solvents have evaporated, any cured film is safe.
How to choose a type of hardwood finishes for your project?
Once the wood surface is prepared and stained, a number of needed finish coats can be applied. Finishes come in a variety of different colors and shines, such as high-gloss, semi-gloss, matte, and satin. Finishing products are grouped based on general working qualities and the degrees of protection they offer. Different finishes offer different levels of protection, durability, reparability, ease of application, and drying periods. There are many types of finishes but commonly used ones include oil-modified urethane, penetrating sealers, paste wax, varnish, shellac, water-based urethane, or even paint. Let’s look closely on each of them.
Oil-modified urethane is generally the most common surface finish. It is a petroleum base with a blend of synthetic resins, plasticizers and other film forming ingredients that produces a durable surface. It is moisture resistant and becomes very hard once it dries. This finish requires putting of 2-3 coats on the surface and takes longer time to dry (approximately 8-9 hours) because oil tends to penetrate deep into the graining of the wood.
Penetrating sealers is made of tung and linseed oil and have solvent based. Normally installers remove the excess sealer after 24 hours of curing. This type of finish often has to stain and seal the hardwood floor.
Paste wax is an evaporative finish because it is dissolved in turpentine or petroleum distillates to make the familiar soft paste. After these distillates evaporate all that's left is the wax. It is relatively easy to apply and repair. Wax is spread in thin coats (1-3) for a surface protection after the stain and/or sealer is applied, after that buffed to the desired sheen. Despite the fact that the paste wax is the least expensive and fastest drying finish, it is very soft and never dries to a hard finish. In other words, it is least durable finish. That’s why some installers believe that it doesn’t protect the wood as good as other finishes. Some of them use paste wax over other finishes, such as shellac or lacquer (not recommended because it is flammable).
Varnish is made from vegetable oils, tough and durable synthetic resins, and a thinner or solvent. Varnish cures by the same process as true oils (polymerization) but the resins make this finish more durable than oil. In fact, oil-based varnish is strong finish that can be easily applied. However, it takes a long time to dry and is very strong-smelling. Good thing about this finish is that it is resistance to water, heat, solvents and other chemicals.
Shellac is a very widely used single component resin varnish that is alcohol soluble. It is not used for outdoor surfaces or where it will come into repeated contact with water. Shellac has been processed to remove the waxy substances from original shellac and can be used as a primer and sanding-sealer substrate for other finishes such as polyurethanes, alkyds, oils, and acrylics.
Water-based urethane is a water-borne urethane with a blend of synthetic resins and other durable ingredients, such as film forming and plasticizers to make it strong and long-lasting that is also moisture-resistant. This choice will eliminate the fire hazard and to mitigate the environmental and health impact. They have a milder odor than oil-modified finishes have. Even though, the finish requires 2-3 coats to put on the surface, the dry period is pretty much fast (approximately 2-3 hours). Water-based urethanes are popular also but are slightly more expensive than most others hardwood floor finishes.
What finishes are more durable?
In order to answer this question, we need to understand that as our life anything is perfect. So, we should consider a finish as a durable one if it is reasonably resistant to normal usage. And as was mentioned above, the durability of a finish is measured by its resistance to water, chemicals, solvents, heat, scratches, etc... Unfortunately, most of finishes will be damaged if exposed to water long enough and scratch easily if you have a dog (dogs) in the house. Wax is resistant to acids. Oil-based polyurethane is the most durable finish you can find.
