Is Water Based Polyurethane Flammable? Know the Truth!

Is Water Based Polyurethane Flammable?

Water-based polyurethane is a popular choice for finishing wooden surfaces due to its durability and ease of application. However, a common concern among DIY enthusiasts and professionals alike is whether water-based polyurethane is flammable. In this article, we will explore the flammability of water-based polyurethane and provide you with the information you need to know.

Understanding Water-Based Polyurethane

Water-based polyurethane is a type of finish that contains polyurethane resins dissolved in water. It is used to seal and protect wooden surfaces while enhancing their appearance. Unlike oil-based polyurethane, which uses a solvent such as mineral spirits, water-based polyurethane relies on water as the primary carrier. The water evaporates as the finish dries, leaving behind a protective layer.

The Flammability Factor

Unlike its oil-based counterparts, water-based polyurethane is not flammable in its liquid state. This is because water is the main solvent used, and water does not burn. Therefore, you can safely handle and store water-based polyurethane without worrying about it catching fire accidentally.

However, it is important to note that even though water-based polyurethane is not flammable in its liquid form, it can become flammable once it is dry. When the water in the finish evaporates, the polyurethane resins form a solid coating on the surface. This dried coating can burn or catch fire if exposed to an ignition source, such as an open flame or a spark.

Is Water Based Polyurethane Flammable? Know the Truth!


Fire Safety Precautions

While water-based polyurethane is not inherently flammable, it is still crucial to exercise caution when working with it. Follow these fire safety precautions to minimize the risk of a fire:

  1. Ensure proper ventilation in your work area to prevent the accumulation of flammable vapors.
  2. Avoid smoking or using open flames in the vicinity of the polyurethane finish.
  3. Do not spray water-based polyurethane near anything that could potentially ignite it, such as electrical equipment or pilot lights.
  4. Store water-based polyurethane in a cool, dry place away from direct sunlight, heat sources, and open flames.
  5. Dispose of any rags or materials soaked with water-based polyurethane in a metal container with a tight-fitting lid to prevent spontaneous combustion.

Benefits of Water-Based Polyurethane

Despite its potential flammability when dry, water-based polyurethane offers numerous benefits that make it a popular choice for finishing wood surfaces:

  • Easy cleanup: Water-based polyurethane can be cleaned up with water and soap, eliminating the need for harsh solvents.
  • Faster drying time: Compared to oil-based polyurethane, water-based finishes dry more quickly, allowing for faster project completion.
  • Low odor: Water-based polyurethane emits fewer fumes and has a milder odor compared to oil-based products, making it more pleasant to work with.
  • Environmentally friendly: Water-based polyurethane releases fewer volatile organic compounds (VOCs) into the air, reducing its impact on indoor air quality and the environment.
  • Durable finish: Water-based polyurethane provides a tough and protective coating that resists scratches, stains, and UV damage.
Is Water Based Polyurethane Flammable? Know the Truth!


Frequently Asked Questions For Is Water Based Polyurethane Flammable? Know The Truth!

Is Water-based Polyurethane Flammable?

Water-based polyurethane is considered non-flammable as it does not contain volatile organic compounds (VOCs) that can easily ignite.

How Does Water-based Polyurethane Differ From Oil-based?

Water-based polyurethane has a lower odor, quicker drying time, and produces less harmful fumes compared to oil-based polyurethane.

Is Water-based Polyurethane Safe To Use Indoors?

Yes, water-based polyurethane is safe to use indoors as it emits fewer toxic fumes and has a lower risk of fire hazards compared to oil-based alternatives.

Can Water-based Polyurethane Be Used On All Surfaces?

Water-based polyurethane can be used on a wide range of surfaces such as wood, concrete, and metal, making it versatile for various projects.


Water-based polyurethane is not flammable in its liquid state, thanks to the water as its primary solvent. However, once the finish dries and the water evaporates, the solid coating can become flammable if exposed to an ignition source. By following fire safety precautions and handling water-based polyurethane responsibly, you can safely enjoy its many benefits while minimizing the risk of fire. Remember to always read and follow the manufacturer’s instructions for the specific water-based polyurethane product you are using.

Updated: January 1, 2024 — 3:00 pm