What is the Difference Between Traditional Varnish and Polyurethane?

Everyone appreciates the elegant look of wood floors, cabinets, and doors, but wear over time can leave the wood in your home looking old and neglected. In order to better preserve the inherent beauty of wood furniture and fixtures, a traditional varnish or polyurethane top-coat finish is usually applied.
The downside is that this protection comes with a hefty cost in terms of harmful chemicals, strong odors, and environmental damage. Let's talk about the different options for protecting the wood throughout your home, including our eco-friendly options to help protect your family at the same time.
Varnish vs. Polyurethane
Varnish and polyurethane are protective finishes used on wood furniture, floors, and fixtures to enhance their appearance and safeguard them from damage.
While varnish and polyurethane are often used as synonymous terms, they are very different products and not interchangeable.
We will walk you through the difference between traditional varnish and polyurethane, and provide you with our products that offer a healthier, more environmentally safe option to traditional wood protectants.
What is Traditional Varnish?
Traditional varnish has evolved to include several derivatives, but the basic product includes a combination of solvents, resin, drying oils, and UV protectors. Furniture makers and woodworkers have traditionally used conventional varnishes to give wood a durable and flexible finish as well as protect it against damage from the sun.
There are three primary elements in varnish that give it the appealing properties that consumers and woodworking professionals desire. Unfortunately, these components also create noxious odors and can present serious health risks:
Resin: Resin is a viscous material in varnish used to give the body of the finish. It is typically made from dammar, copal, balsam, sandarac, and other organic materials.
Drying Oil: When exposed to air, drying oil forms a hard film surface. There are several different drying agents including tung and walnut oil.
Solvents: A solvent allows the base material to cure as it evaporates. Turpentine is still used extensively in varnish products, but mineral-based substitutes have grown increasingly popular.
In addition to the potential side effects, applying a conventional varnish finish isn't particularly easy, and those with experience usually get the best results. If done improperly, conventional varnish can bubble, peel, crack, delaminate or never fully harden.
It is also important to apply conventional varnish in an environment free of dust, dirt and other contaminants. In most cases, several coats are required to produce the desired effect, which can lead to delayed projects and messy mistakes.

What is Polyurethane?
Polyurethane is a sealant and finish product that is used to protect and enhance fine wood floors, cabinets, and furniture. While it is similar to varnish in terms of application and appearance, polyurethane is generally harder and more abuse resistant, which means it is commonly used for sealing wood floors. It's less flexible than varnish, so it may not be the best choice to use on wood pieces that move or flex.
Water-based polyurethane finishes are comprised of a resin suspended in water and solvent. As the water evaporates from the resin, the material transforms from a liquid into a film. Oil-based polyurethane cures in a slightly different way. The solvents evaporate from the material, which allows the oils and resin to harden, creating a protective layer.
Polyurethane Toxicity Issues
Water-based polyurethane can have less of an offensive odor when compared to oil-based products, but floors require at least four coats to achieve the desired level of protection. While oil-based polyurethane only needs two or three coats, the odor may be so strong the home is uninhabitable for several days.
At its core, polyurethane is a petrochemical resin that contains isocyanates. Uncured polyurethane can aggravate a variety of different breathing problems including allergies, asthma and bronchial conditions.
Additionally, those who are exposed to the fumes may develop vision difficulties, throat irritation, nausea, uncontrolled coughing, vomiting and headaches. Isocyanates contain compounds that are classified by the EPA as potential human carcinogens.

Traditional Varnish Toxicity Issues
The resins and solvents used in varnish are toxic if ingested. Many varnish products contain benzene, which is a known carcinogen that is highly flammable. The solvents in varnish are extremely pungent, and the fumes can cause drowsiness, headaches, skin irritation and dizziness.
At high concentrations, a person may become unconscious, suffer respiratory distress, and may even develop pulmonary edema. Those who apply varnish should always wear a mask, and those with respiratory conditions such as asthma may want to avoid contact with varnish completely.
Breathe Easier with ECOS Paints' Zero-VOC, Water-Based Varnishes
To address the toxicity issues associated with traditional varnishes and polyurethanes, we have developed our water-based varnish product that is non-toxic* for human health and has no polyurethane odor**.
ECOS varnishes are designed for use on furniture, cabinets, floors, woodwork, and doors and are available in a wide array of sheens. The water-based varnish has exceptional clarity and durability, and it can be applied with the same applicator tools commonly used with polyurethane.
When you use any of our zero-VOC, environmentally friendly finishes, you can feel assured that you are protecting your home without exposing your family to harmful fumes and chemicals. Shop now to keep your wood looking damage-free by protecting it from everyday wear and tear!
*Non-Toxic: Conforms to ASTMD-4236, specifically concerning oral toxicity, skin irritation and respiratory effects.
** No Polyurethane Odor: Polyurethane can cause headaches, nausea and respiratory issues. Conforms to ASTM E544 & ASTM MNL13.