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.
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.
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 — 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.
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.
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.
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.
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.