POLYURETHANE
When to choose Water or Oil-Based?
Two types of wood flooring polyurethane exist: water and oil base. Polyurethane is the protective finish applied to hardwood floors after sanding is complete. Typically three coatings are applied when the natural look is to be achieved. If staining of the floors is the desired look then the polyurethane is applied afterwards. But what type of polyurethane is best for your floors? One type of polyurethane is not necessarily better than the other however there are circumstances when you may choose water-based over oil-based or vice versa.
COLOR:
Oil-based polyurethane leaves an amber glow which darkens over time.
Water-based polyurethanes provide a clear finish that will remain clear for a longer time.
Sheen:
Polyurethane in general comes in three sheens: satin, semi-gloss and gloss.
Oil-based polyurethane typically has a higher sheen than water based polyurethane. Although the sheen will vary depending on manufacturer.
Durability:
Oil based polyurethane contains more solids which create the protective floor finish thus making the end product more durable than water based.
Often water-base treated floors need a re-coating sooner than and oil-base treated floor.
Volatile Organic Compounds (VOC’s):
Oil based polyurethanes have a higher level of VOC’s
Water based polyurethanes have lower VOC’s
VOC’s are the emitted gases when the polyurethanes are drying.
SMELL:
Oil based polyurethane has a strong odor which dissipates as the finish dries.
Water based polyurethane, on the other hand, has a low odor.
DRYING TIMES:
The dry time for oil base polyurethane is about 8-10 hours. Usually a day between coatings.
The dry time for water base polyurethane is about 4-5 hours.
(Dry time is always dependent on the temperature and relative humidity).
Cost:
Oil based polyurethanes are less expensive than the water-based which can be almost triple the cost.
Circumstances that require water-based polyurethane:
In some cases you may choose water based polyurethane over oil. For instance if you stained your floors gray or white the clear water-base finish will maintain the stained color without yellowing. Others prefer the natural look of sanded floors or the light tone of maple floors which is maintained with a clear finish. In other circumstances such as condominiums or apartment buildings, offices, museums a water-base finish is required due to the low VOC’s which have less odor.
Product:
I would be remiss if I did not mention that the product/brand of polyurethane applied to your floors does matter. Simply put, an inferior product will affect the finished product.
At Frank H. Duffy Inc., Duffy Floors, we only use high quality polyurethanes such as Woodline and Traffic by The Bona Company.