Can You Sleep In House After Polyurethane?

Coating your hardwood floors with polyurethane is essential for their proper maintenance. But should you stay at home after its application or should you make arrangements for a place to stay in the meantime? That's what we asked experts, and here's what they said.

It is advised that you don't sleep in your house for at least two days after applying polyurethane on your wood floors. This wood sealant contains isocyanates and VOCs that are harmful to your health once you inhale them.

Keep on reading so we can explain further why you need to stay away from your house after you use polyurethane on wood floors. We'll also tell you the harmful effects of polyurethane and discuss its two types as well as their advantages and disadvantages. This article will also answer if polyurethane is cancerous and how long it takes before the coating on your wood floors is fully cured. Let's get this started!

Squeegee Style Brush Applying Clear Polyurethane to Hardwood Floor , Can You Sleep In House After Polyurethane?

Can you live in your house while refinishing hardwood floors?

The carpenter is wearing a polyurethane on a teak floor.

Wood floors provide your home with a classic and timeless style. They certainly add value to your home. But they don't come cheap.

To protect this major investment from damage, it's best to coat it with polyurethane wood sealant and recoat it when the need arises. Otherwise, your hardwood floors would be prone to scratches, stains, and even pest infestation. Polyurethane acts as a shield against external elements so that your wood floors would last longer.

However, you have to plan well for your polyurethane application. You need to make arrangements where you can stay for a few days to protect your best health after this wood treatment.

Polyurethane contains isocyanates and harmful gases or VOCs. Once this sealant is applied on your wood floors, it would be gassing off or releasing toxic gasses into the air.

Experts recommend staying away from your house for at least two days for your safety. If you have a place where you can stay longer, that's even better.

The fumes and odors of this sealant could even stick to your walls, curtains, and other parts of your house. So the chances of inhalation of harmful gasses are still very high even after the sealant has dried.

It would only be safe once the polyurethane has completely cured. It could take days for water-based wood sealants and weeks for oil-based ones.

Two types of polyurethane

Polyurethane is a class of polymers that exists in different forms. It is essentially a plastic material that can come in rigid or flexible variants to suit your particular needs. It can be used for cushioning, mattresses, adhesives, coatings, to name some of its numerous applications.

What we're concerned about here is the polyurethane that's used for coating floors and other wood structures. There are two types of polyurethane that you can use to coat your hardwood floors - water-based and oil-based.

The type that you would choose would determine how soon you could sleep in your house after its application. While we're at it, let's discuss the pros and cons of each type so you can make the right choice and preparations after their application.

Water-based Polyurethane

This is a thin solution that has a clear color. It will not alter the look or color of your wood floor. This polyurethane is less flammable and doesn't contain any harmful VOCs, so it's safer to use. As you apply it on your floors, there won't be any strong odors or fumes.

This polyurethane type also dries quickly, after about two hours, so you can reapply your second and third coating within the same day. Yes, you would need several coats to make your finish durable because this type is composed of fewer solids.

Cleaning isn't a problem. You can simply wipe off the dirt and spills on the surface. You may also use soapy water when needed.

Water-based polyurethane is more expensive. It costs twice as much as oil-based sealants. They also aren't as durable which is why you would need to reapply the coating every two years.

Check out this water0based wood sealer on Amazon.

Oil-based Polyurethane

Oil-based polyurethane sealants are made up of 45% to 50% solids. This is why they are more durable than the water-based type. Because of this, you would only need a few coats of this sealant to give your floor the protection that it needs.

They also come with an amber hue that gives hardwood floors a rich glow which is why they stand out even with little maintenance from your end. Lastly, this type is more affordable than water-based sealants.

Click this link to find this oil-based wood sealant on Amazon.

However, oil-based polyurethane emits a very strong odor and toxic fumes. It contains a high level of VOCs which can be dangerous to your health. It also takes much longer to dry. You have to wait for about five hours before the next coat. If you need to apply for three coats, the job would take three days.

Since the fumes from oil-based wood sealants can be toxic, you would need to go find a place to stay for a week or two. To help it dry and get rid of the odor faster, you can leave the windows and doors open to keep it well-ventilated.

You can also turn on your fans and heater. It is also recommended to use an air purifier once you come back to help clean the air from these harmful substances.

Are polyurethane fumes harmful?

Squeegee Style Brush Applying Clear Polyurethane to Hardwood Floor

We've been talking about polyurethane being harmful to your health. Among all the paints and coatings, it is said to be the most dangerous. But how exactly can it affect your body?
Polyurethane contains isocyanates that are considered toxins to our respiratory system. As long as this sealant hasn't been fully cured yet, these toxins are present in the air that you breathe.
They can trigger asthma attacks. Those who inhale these fumes might also experience headaches, nausea, vomiting, throat and eye irritations, coughing, shortness of breath, and other respiratory concerns. 
Keep in mind that kids and family members with existing respiratory conditions are more vulnerable to this. That's why it would be best to keep them away from the house until the polyurethane has fully cured. 

Is polyurethane cancerous?

Pouring Polyurethane Clear Coat on Hardwood Floor

There have also been concerns about polyurethane causing certain kinds of cancer. This is not yet proven. However, studies have shown that the ingredients of this particular wood sealant are carcinogenic to animals. 
The said ingredients are toluene diisocyanate and methylene diphenyl diisocyanate, which can be found in large quantities in polyurethane products. They can cause blood, liver, lung, and other cancers in animals. 
Based on these results, experts recommend that we take extra precautions as polyurethane can probably be carcinogenic to humans as well.

How long does it take polyurethane to cure on floors?

As mentioned earlier, the toxicity of the VOCs and isocyanates in polyurethane wood sealants will only be gone when they have been given sufficient time to cure. 
Let's clarify that drying is different from curing. It may only take hours for each coating to dry, after which you can put another coat of sealant or you can walk on the surface as long as you're wearing socks.
After about two to four days, your wood floors are ready for use. You can bring back your furniture. But it isn't advisable to put an area rug in the meantime as it would prevent the gasses from the sealant from fully escaping.
Meanwhile, it would take up to a month for this wood sealant to cure completely. This is when the sealant hardens to form a durable protective cover over your hardwood floors and fully adheres to the surface underneath.
Curing time would depend on the:
  • type of polyurethane sealant and the formula used,
  • the number of coats,
  • and the humidity level after the application.
Water-based sealants take 20 days to fully cure while oil-based polyurethane would take 30 days. Certain formulas are fast curing, so this can speed up the waiting time.
The more coats applied on the surface, the longer it'll take to cure. The temperature has to be warm enough but not too dry so as not to cause cracking on the polyurethane's surface. 

Final Thoughts

Squeegee Brush Applying Clear Polyurethane to Hardwood Floor

If you're having your wood floors refurnished with polyurethane, make sure you have a place where you can stay at least until the worst of the off-gassing is over. This is for your good as inhaling its toxic fumes is dangerous to your health.

For more resources related to house painting, feel free to visit the following links:

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