Whether you choose to paint, stain, or apply urethane to your wood, it will inevitably smell. This is especially true for oil-based polyurethane. That being said, water-based polyurethanes give off much less of an odor than oil-based urethanes and other varnishes.
Though its smell is less pungent than other products, there are a few ways you can minimize its odor and avoid the unpleasant side effects that come with it.
What Is Water-Based Polyurethane?
All water-based polyurethanes will give off an unpleasant odor, but much less so than oil-based poly. This is partially due to the quicker dry time of water-based products and their ingredients.
Polyurethanes are made of a mixture of polymers and urethanes that create a chemical reaction that produces a liquid plastic-like product. Water-based polyurethanes use different ingredients in their production process than oil-based urethanes, which is why they give off much less of an odor.
Water-based poly contains water, as opposed to solvents, as a medium to apply the urethane to a surface. Oil-based products instead use petroleum and mineral-based solvents as a medium for the urethane.
Urethanes get their distinct and intense smells from the volatile organic compounds (VOCs) that they contain. These VOCs are released into the air once we crack open a new can. They are most noticeable when we first start applying them, but the fumes dissipate as the urethane dries.
Does Water-Based Polyurethane Smell?
Water-based polyurethane’s smell is considered less offensive when compared to oil-based urethanes, but it isn’t completely odorless. Since there are fewer VOCs and other smelly solvents in water-based products, they don’t emit as strong of an odor, and their smell doesn’t linger as long.
If you are applying water-based poly in a small unventilated room, you will most certainly notice its fumes. When working on an outdoor project or in a well-ventilated room, the fumes may barely be noticeable.
The urethane will produce the most odor while it is still wet, and it will continue to smell until it fully cures. Most of the fumes will be gone after a few hours once the layer has had time to dry, but you may still notice that chemical smell for up to 2 weeks when it has fully cured.
Choosing a satin, semi-gloss, or gloss finish will affect the dry time of your project as well. This won’t greatly affect the dry time, but satin finishes tend to dry slightly faster than their glossier counterparts.
Are Polyurethane Fumes Harmful?
Polyurethane is carcinogenic, meaning it shouldn’t be breathed in. Side effects from the fumes include headache, dizziness, nausea, confusion, and even loss of consciousness.
This is why it is so important to wear proper protection and properly ventilate the room that you are working in.
How to combat the smell of water-based Polyurethane?
Combating these noxious fumes is important, no matter how big or small your project may be. At the very least, it can save you from an unwanted headache or nauseous feeling.
Proper Ventilation
Properly ventilating the room that you are working in is the easiest and safest way to avoid inhaling unwanted toxic fumes from water-based polyurethane. This includes opening as many windows as possible and using a fan to push the fumes out of the area.
Properly ventilating a room will also help speed up the dry time of the urethane, reducing the total time of your project.
Personal Protection Equipment
PPE is always a good idea when undergoing any construction project, especially when using potentially dangerous materials like polyurethane. This includes eye protection and a respirator.
Eye protection will prevent any splashes or droplets of polyurethane from getting into your eyes, which can be painful and cause lasting damage to your eyesight.
Most professionals will only use a respirator when using oil-based polyurethanes, but it is always better to be safe than sorry. Even though water-based polyurethanes give off much less odor than oil-based products, the toxic fumes can build up in a small unventilated room. A respirator will guarantee that none of the harmful chemicals get into your lungs.
Consider Temperature & Humidity
Temperature and humidity play a major factor in the dry time of water-based polyurethane.
Colder temperatures will slow the drying process, causing the fumes to hang around for a longer period of time. It will dry faster in warmer temperatures, but extremely hot temps can cause urethane to dry too quickly and damage the look of your finished product. Check the directions on your can of urethane for the ideal temperature, it should be somewhere between 60 and 70 degrees Fahrenheit.
It’s no surprise that high-humidity areas are not good for dry times of water-based products. This can be hard to control, especially if you live in a humid climate, but it isn’t impossible.
Consider the weather on the days you want to apply polyurethane, even if you are working on an interior project. Opening the windows for ventilation on a rainy day will only let in moist air and may hinder the dry time of your urethane.
Picking a warm day where the temperature isn’t too high, and the humidity is low is a great way to ensure a quick dry time. If the weather is uncooperative, you can always introduce a space heater to the area to raise the temperature as long as you don’t directly apply the heat to the surface.
Preparation Is Key
Sand your surface, wipe clean with a cloth, then vacuum the excess dust. Skipping any of these steps will cause your urethane to adhere unevenly and leave an ugly coat. This means you will have to start from square one and reapply your coats of poly, extending the amount of time you will be exposed to the toxic fumes.
Final Thoughts
Although oil-based products are more known for their overwhelming smell, water-based polyurethanes can be just as pungent in the right conditions. They are unpleasant and harmful to breathe in, but with a little planning, you can avoid this problem altogether.
Always make sure to ventilate the room you are working in, wear proper protective equipment, consider the outdoor temperature and humidity, and prep your project so that you don’t have to start over.
