Many homeowners confuse pre-finished floors with site-finished wood floors.

Site-finished wood floors consist of boards of raw oak which are installed and then sanded insided the home. Custom color is added to the entire floor and then sealed with multiple coats of polyurethane. This produces a very even and consistent look.

Pre-finished wood floors are comprised of boards sanded, stained, and coated individually at the factory. The finished boards are installed and the process is complete.

Pre-finished wood is becoming the product of choice for many homeowners.

It offers several benefits over site-finished hardwood including a more durable and flawless finish. The finish is harder than standard polyurethane because it contains different elements, such as aluminum oxide, which are cured with ultraviolet light. This is not something that can be done on the job site because it requires special equipment in a dust free environment. Boards finished under controlled conditions will also have fewer defects in the finish such as debris, a more uniform color, and fewer puddles or drips since the stain and finish are applied mechanically.

Homeowners often notice a slight difference in height from one board to another on a pre-finished wood floor. This is called over-wood or lippage and is defined as the vertical distance between two abutting boards. Pre-finished boards are manufactured to be within a certain tolerance and may have a slight variation in height from board to board. Due to the fact that the boards are sanded at the factory prior to installation, some deviation between the individual planks is unavoidable. Typically the boards come from the factory with a maximum deviation the height of a business card.

Sanding a site finished hardwood floor creates a level surface which has had all the uneven edges smoothed to the same height. Because this is done on site, sanding masks any deviations in the sub-floor as well. No sub floor is perfectly level, even after careful preparation for hardwood installation. Pre-finished boards sometimes exacerbate natural deviations in the sub-floor and create a situation in which boards that are basically the same height can appear to be slightly uneven. Square-edged boards as opposed to beveled edged boards will seem to show over-wood more due to the fact that they are designed to be flush board-to-
board whereas beveled edges are designed to slope down and outward.

Some over-wood in a home is perfectly normal and does not indicate a flaw in the boards or unacceptable deviation in the sub-floor. Nor does it affect the integrity of the floor. The National Association of Home Builders Residential Construction Performance Guidelines describes over-wood as lippage. According to their standards, Lippage under 1/16 of an inch (about the size of a credit card) is considered to be within tolerance.