Home woodworking enthusiasts, us included, work with polyurethane often. It’s an easy-to-apply, easy-to-use wood finish that is a suitable topcoat for both stained and painted pieces and is inexpensive. We’ve written on these pages of polyurethane before, most recently in answer to the question of how many coats of polyurethane you should apply.
Key Points:
- Polyurethane is an easy-to-apply and inexpensive wood finish that protects pieces from water and other damage.
- Water-based and oil-based polyurethane have distinct differences in application and drying time.
- Polyurethane shouldn’t be taken lightly, as it emits a noxious odor when drying, which can be toxic, and take precautions should be taken to properly ventilate the area in order to reduce smell.
How Does Polyurethane Work As A Wood Finish?
Polyurethane has two main components, polymers, and urethane, that make it an excellent topcoat for wood projects. When it dries, it forms a hard plastic sheet on the wood that keeps water out, resists damage from heat, and offers a durable and long-lasting surface that does not dent or scratch easily.
Polymers are a kind of plastic, if you will, to keep the definition in fairly simple terms, both natural and synthetic. Examples of natural polymers include silk, wool, and proteins; examples of synthetic polymers include nylon, epoxy, and Teflon. Urethane falls in between a plastic and rubber, probably more so into the rubber category.
Other components of polyurethane include flatteners, added to lessen the gloss of the dried finish. VOCs, volatile organic compounds, are present in polyurethane, and they are emitted as gasses as the poly dries and cures. They are toxic and can cause harm to living things, humans and animals, and are not to be treated lightly.
As polyurethane dries and cures, this plastic/sort-of-rubber product will solidify into a hard and durable sheet of plastic on the wood’s surface. It offers protection from water, heat, dents, and scratches.
Water-Based Polyurethane and Oil-Based Polyurethane
The constituent parts of polyurethane, polymers, and urethanes are suspended in a medium for delivery. Water is one; oil is the other, two different polyurethanes with distinct differences, each offering features that might be needed for a particular use.
Water-based polyurethane is thinner than its oil-based cousin and dries quicker. Thin means you probably want to use more coats, depending on what it is being applied to, and we addressed that in our earlier piece referenced above. It dries fast enough, though, for you to be able to apply two coats, at least in a day, and keep your project moving along to completion.
Oil-based polyurethane is the thicker of the two. That thickness, coupled with the oil medium, means it will take much longer to dry than the thinner, water-based polyurethane. With a greater volume of VOCs, the toxic gasses emitted will be greater and more offensive to our smell.
Working with an oil-based polyurethane does require a greater degree of care. A respirator should be worn, as the chemicals and gasses can cause eye, nose, throat, and lung irritation and damage; the room should be very well-insulated and with a lot of ventilation to allow the gasses and smells to escape. Because the oil-based polyurethane takes a long time to dry, those gasses and smells will be with you for a long time, so be prepared.
Does Polyurethane Smell?
As we have just said, polyurethane does smell, and not in a pleasant way.
In answer to the question, what does polyurethane smell like? It’s a difficult smell to describe: chemical in nature, irritating and unpleasant, and you really should be wearing a respirator when working with it. Once you’ve smelled the odor of polyurethane, you will always remember it.
Polyurethane odors are noxious and toxic, and polyurethane is a known carcinogen. Proper care is essential when using it. Getting rid of the distinct polyurethane smell and the fumes should be a priority when using either type of poly, and odor removal should be a part of your project plan when using it as your finish, as health issues can arise.
For How Long?
How long the smell of polyurethane lingers depends on a number of factors:
- What was it applied to? Read on.
- How many coats were applied? Obviously, the more you use, the longer to dry and the longer to smell.
- What type of polyurethane was used? Oil-based is the culprit, while water-based is fairly benign
- How well-ventilated is the space where it was used? Crucial when using an oil-based poly.
When using an oil-based polyurethane, you can expect the toxic fumes to linger at their worst for 5 – 7 days. However, a milder odor will linger for another 2 – 3 weeks in the case of water-based polyurethane and 3 – 4 weeks in the case of oil-based poly.
Once polyurethane has dried and cured, though, the toxic fumes will have dissipated and will no longer be harmful. It is only when it is still wet and releasing the VOCs. The potential health issues are very real, and care is essential for your well-being and the well-being of those in your house and home.
Hardwood Floors And Oil-Based Polyurethane Odor
Now that you know of the smells, the toxic fumes, and the harm that can be caused if proper care is not exercised, let’s talk about specific projects where polyurethane will be used. Finishing a hardwood floor is one such project. Most floor finishers prefer an oil-based polyurethane for hardwood floors, so we are talking about the oil-based type of poly here. Water-based polyurethane does not have the odor or the degree of VOCs and dries/cures quickly.
Imagine an entire household filled with the odor of polyurethane when its floors have been finished (if new construction) or refinished (in an existing home), let alone its toxic fumes. With human health issues at stake, this is a major issue that requires careful planning – whether for the workmen finishing the floor or your family.
Air purifiers like those we hang from our car mirror will not do the trick, and neither will spray air fresheners. Something more substantial is required.
- Move out of the house. You and your family should not remain in the house while a polyurethane coating is drying and curing on your floors.
- Open windows throughout the house to allow as much ventilation as possible to the area affected.
- Odor eaters like distilled white vinegar, baking soda, and activated charcoal can be effective in lessening the smell. A bowl or paper plate of baking soda or activated charcoal in the room(s) affected can help, but to a lesser degree than good ventilation. Lemons and lemon juice can also help.
- We like a product called Damprid moisture absorber with activated charcoal. A canister or three with an open grate on top will also help reduce substantially, but not eliminate altogether, the smell of polyurethane finishes. As an aside, it also works very well in damp areas generally – under the kitchen sink, under the bathroom sink, etc.
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Furniture and Polyurethane Odor
With furniture, the problem is much easier to manage. That new chair, shelving, desk, or table can simply be left in the garage while the polyurethane varnish dries and cures. Then, when it’s safe and odor-free, the piece can be brought inside. There will be plenty of ventilation in the garage, and no one to harm by the strong fumes or smells.
Yes, polyurethane smells and smells bad. The fumes are toxic and can cause serious health issues – shortness of breath, eye, nose, throat, and lung irritation, and even allergic reactions. Respirators are essential with the use of oil-based polyurethane, as well as gloves. Air circulation and adequate ventilation of the room(s) is essential.
Take this seriously, and take all necessary precautions. Your health is somewhat at risk, and that’s serious business.
Last update on 2023-06-06 / Affiliate links / Images from Amazon Product Advertising API
