After sanding or installing a new hardwood floor, a polyurethane finish is applied to protect the wood and bring out the astonishing grain. For a lasting protection, polyurethane need to dry and cure completely before resuming normal activities. This brings us to a question – how long does it take for polyurethane to dry?
A fully cured wood sealer protects the underlying wood from water and moisture damages, prevents the grain from rising and adds color or depth to the wood. However, there are factors that will determine the amount of time or duration it takes for a sealer to fully cure.
A wood sealer is considered to be dry when the surface does not feel sticky to the touch and doesn’t appear wet. At this point you can walk on the floor bare footed without feeling tacky. To avoid causing surface blemished, avoid walking in shoes or placing any weighty objects on the floor until you are sure the finish has dried.
A fully cured polyurethane takes place after the molecules have been allowed enough time, usually 30 days to interact with oxygen. This makes them strongly bind together and to the underneath wood. This is when you can confidently allow in foot traffic and resume normal operations on the floors.
Polyurethane Curing and Drying Time
Polyurethane is a commonly used wood sealer that usually dries in 24-48 hours and takes up to 30 days to fully cure. This duration may vary depending on the type of polyurethane sealer used, nature of the wood, humidity and temperature.
1. Type of polyurethane
There are two types of polyurethane namely; oil-based and water-based. Polyurethane is made by dissolving a resin compound into a solvent. After applying the sealer onto wood, the water or oil into which the polyurethane resin is dissolved evaporates overtime leaving behind a plastic like coating on the wood.
A water based polyurethane is odorless, dries quickly, cleans easily with water and will not yellow with age. Six hours after application, wood should appear dry and should not feel tacky to touch. At this point, do not walk over in shoes or allow in pets.
After 12 hours, sanding can be done and another coat can be added. Remember to clean thoroughly after sanding. After 48 hours water based polyurethane is dry and you can wear shoes and bring back furniture. Do not cover the surface with rugs until 30 days when the poly has fully cured.
Oil based also known as solvent based-polyurethane is a more 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 fee tacky to the touch. Although you should not wear shoes or allow in pets. You can also sand for an additional coat.
Four days after application of your oil based finish, you can walk over in shoes, bring back furniture but do not cover the surface until the 30 days are over when the varnish has fully cured.
2. Nature of the wood
There are some wood species that produce chemical substances and natural oils that inhibits or delays the normal drying or curing time of a polyurethane. Rosewood and aromatic cedar of such woods.
A properly sanded wood presents an open grain surface that readily absorbs polyurethane for a fast drying. However, subsequent coats may take longer to dry. Dust and other ingrained dirt can delay drying time for a polyurethane on the wood. It is therefore a good idea to adequately prepare your wood before a sealant is applied.
3. Weather elements
Polyurethane will take longer to dry during cold wet days as compared to dry windy days. Higher temperatures and lower humidity days are likely to fasten drying of polyurethane. It is therefore a good idea to be aware of the weather of the day you are planning to refinish your wood floor.
Polyurethane is applied using a bristle or foam brush. Before you begin, clear the room, sand the wood and clean it thoroughly to remove dust and any dirt. Decide on the number of coats that will be needed. Choose one of the best hardwood floor finishes and start your task. Follow the manufacturer’s instructions, wear protective gloves, and gas mask then apply your finish.
Too many coats may delay drying, form surface wrinkles and makes 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 somehow 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 very shiny and slick surface. High gloss varnishes takes quite longer to dry and cure.
Semi-Gloss – The finish Dry to a sheen between high gloss and flat. This sheen is common on woodwork, furniture, doors, floors and cabinets. Semi-gloss finishes takes moderate amount of time to dry and fully 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 usually a fast drying formula.
Polyurethane is type of finish which offers a strong wood protection and beautiful looks. Drying time is one of the factor to look at when choosing a polyurethane for a wood flooring project. Always allow recommended curing and drying time for durability, maximum protection and appealing outcome.