How Long Does it Take for Polyurethane to Dry?

Polyurethane is a finish layer applied after sanding or installing a new hardwood floor to protect the wood and highlight the wood’s natural grain.

A cured wood sealer protects the underlying wood from water and moisture damage, prevents the grain from rising, and adds color or depth to the wood.

For lasting protection, polyurethane needs to dry and cure before you resume normal activities. This brings us to a question – how long does it take for polyurethane to dry?

There are multiple factors that determine the amount of time it takes for a sealer to cure.

How Long Does it Take for Polyurethane to Dry

A wood sealer is dry if the surface neither feels sticky nor appears wet.

At this point you can walk on the floor barefoot without your feet feeling sticky. To avoid causing surface blemishes, avoid walking in shoes or placing any heavy objects on the floor until you are sure the finish has dried.

Polyurethane cures after molecules interact with oxygen for some time.  This creates a strong bond between the polyurethane finish and the underlying wood.

Once the floor is cured, you can allow in foot traffic and resume normal operations on the floor.

Polyurethane Curing and Drying Time

Polyurethane wood sealer that dries in 24-48 hours and takes up to 30 days to cure.

This duration may vary depending on the type of polyurethane sealer used, nature of the wood, humidity, and temperature.

Type of polyurethane

There are two types of polyurethane: oil-based and water-based. Polyurethane is made by dissolving a resin compound into a solvent.

After applying the sealer, the water or oil evaporates from the polyurethane resin, leaving a plastic-like coating on the wood.

Water-based polyurethane

A water-based polyurethane is odorless, dries quickly, cleans with water, and will not yellow with age.

Six hours after application, wood should appear dry and should not feel sticky to the touch. At this point, do not walk in shoes or allow in pets.

After 12 hours, sand and recoat as needed. Remember to clean after sanding.

After 48 hours, water-based polyurethane is dry and you can wear shoes and replace furniture. Do not cover the surface with rugs until 30 days after the polyurethane has cured.

Oil-based polyurethane

Oil-based — known as solvent-based — polyurethane is very durable and the best option for humid or high traffic areas.

Oil-based sealer is more resistant to wear, moisture, solvents, and heat. The only problem with this finish is yellowing with time.

Oil-based polyurethane takes more time to dry and cure. During application, the area need to be ventilated. 24 hours after the application, the wood should not feel sticky to the touch.

However, you should not wear shoes or allow in pets. You can sand for an additional coat.

Four days after application of your oil-based finish, you can walk in shoes and replace furniture, but do not cover the surface until the 30 days are over when the varnish has cured.

Nature of the wood

There are some wood species that produce chemical substances and natural oils that inhibit or delay the normal drying or curing time of polyurethane.

Rosewood and aromatic cedar are examples of such woods.

A properly sanded wood presents an open grain surface that absorbs polyurethane for fast drying.

Subsequent coats may take longer to dry. Dust and other ingrained dirt can delay drying time for polyurethane on the wood.

It is a good idea to prepare your wood before a sealant is applied.

Weather elements

Unsurprisingly, polyurethane will take longer to dry during cold, wet days as opposed to dry, windy days. Higher temperatures and lower humidity will hasten the drying of polyurethane.

We suggest you be aware of the weather on the day you are planning to refinish your wood floor and take it into account when considering drying times.

Application

Polyurethane is applied using a bristle or foam brush. Before you begin, clear the room, sand the wood, and clean it to remove dust and any dirt.

Decide on the number of finish coats needed. Choose one of the best hardwood floor finishes and start your task. Follow the manufacturer’s instructions, and wear protective gloves and a respirator mask while applying your finish.

Too many coats may delay drying, form surface wrinkles, and make the whole project unappealing. Adhere to the guidelines and allow humble time for the sealer to dry and cure.

Sheen

Polyurethane finishes are available in three different sheens, each offering different features and a difference in drying time.

High Gloss – This is a tough yet flexible finish suitable for both interior and exterior finishing.

The high gloss polyurethane gives a shiny and slick surface. High gloss varnishes takes longer to dry and cure.

Semi-Gloss – The finish dries to a sheen between high gloss and flat. This sheen is common on woodwork, furniture, doors, floors and cabinets.

Semi-gloss finishes takes a moderate amount of time to dry and cure.

Satin – A satin polyurethane finish provides a durable matte surface and gives wood a subtle gloss, a slight shine, and an extra color.

It is a fast drying formula.

Do you buff hardwood floors after polyurethane?

Yes, definitely! Simply coating your hardwood in polyurethane and calling it quits is not going to leave you with the gorgeous finish you’re lusting for.

Following the first coat, you can expect to see the following: raised grains, loose fibers, brush marks, bubbles, an uneven sheen, even a rough surface and lap marks or trapped particles, which is particularly common after using polyurethane.

What you need to do is get yourself some 180-220 grit sandpaper or screening, then give your finish a thorough buffing all over. This should help to remove all of the above problems we’ve outlined, and once you’ve vacuumed up the mess, swept up any remaining bits and given things a good mop, you should have the shine you want.

However, in the event that you still have an uneven sheen or strange coating after sanding down, it might be advised to apply a more even second layer of polyurethane, being sure that you’ve stirred the mix more thoroughly this time to ensure everything is incorporated and there are no lumps or clumps.

Of course, you’ll have to sand it down again, so be prepared for a few days of work here! But as long as you do everything right, there’s no reason why one coat won’t have your floor looking just like you want it to. 

Should I sand between coats of polyurethane on hardwood floors?

You don’t have to, but it certainly helps! Waiting approximately four to six hours for the finish to dry and then applying another coat of polyurethane without sandpapering will not give a massively different result than if you had sanded, but if you’re striving for perfection, it’s worthwhile. 

If, between coats, you find there are brush marks, bits of dust or other nitpicky areas, you might find sanding smooths them all away, as well as preparing the layer to be re-coated, which also results in a smoother finish for the next one!

If you’re applying each coat immediately after the latter has dried, in around four to six hours for instance, then you shouldn’t find the need to sand the floor before applying your next one. Leave things longer than twelve hours, though, and you’ll definitely want to give things at least a gentle sanding before you recommence.

How often should you polyurethane wood floors?

It depends on several factors! If you do an incredible job at applying perfect coats of polyurethane, with a glorious shiny finish that isn’t marred by imperfections, and you rarely have people in the house to walk over your floors – or the parquet is in a room with little foot traffic – then you’ll probably be able to wait around six years before you have to do it again.

However, if you’ve got a large family, a lot of foot traffic in your home, or your attempt at polyurethane coating didn’t go as perfectly as you’d have liked the first time, you may want to consider giving it a makeover after around four years instead!

The trick is not to wait until the wear and tear is obvious and starts to show, but to recognize that things have dulled down considerably and could use a refresh.

Likewise, how regularly you deep clean your floors and remove any dirt buildup will also determine how often you’re going to need to repeat the polyurethane process; that being said, even the most professionally applied, well-maintained coating is going to need a revamp after a couple of years. When those scuffs and scratches stop disappearing after a deep clean and buff with polish, it’s time to bust out the recoating stuff.

Do you have to seal hardwood floors before polyurethane?

Definitely, yes! If you’ve got an unfinished hardwood floor on your hands, then you’re going to want to apply a single coat of sealer to protect it. This is a very important step when you’re sealing, but particularly when you’re finishing with polyurethane, as it will protect your precious hardwood floors from panelization. 

Especially for those who live in hot and humid climates, if your floor is exposed to moist and damp conditions, it’s likely to develop large cracks, because where normally hardwood would expand and then shrink after being exposed to liquid, the polyurethane locks everything in place, preventing the pieces from contracting the way it is supposed to and resulting in unsightly damage.

Boards can even split right down the middle or at the edge, causing further structural issues with the subflooring, which is a big problem when left untreated. Plus, where things start to protrude from the floor, it could also present a trip hazard.

Although it adds an extra step to your process, you should definitely seal up your hardwood floor before treating it with anything, but this advice is especially important when you’re making use of polyurethane.

Conclusion

Polyurethane is type of finish which offers a strong wood protection and a beautiful look.

The drying time is one of the factors to consider when choosing polyurethane for a wood flooring project.

Allow the recommended curing and drying time for durability, maximum protection, and the most appealing outcome.

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