Problem: Crowning of Hardwood Flooring Boards
Cause:
Sanding of wet hardwood.
Crowning is cause when flooring absorbs moisture on the underside and expands, raising the outside edges of the boards in a cup-like fashion. If the floor is sanded while in this cupped position, the edges of each board will become thinner than the rest of the board. When the boards subsequently dry, the outside edges return to their original positions, which will then be lower than the rest of the board surface as shown in Figure 34.
Figure 34 - Crowning Of Hardwood Floor Boards.
Solutions:
Protect wood from changes in humidity.
- Wood flooring must be protected from excessive changes in humidity so that its moisture content remains relatively stable. If it is installed over an area of higher humidity, protect it by placing a moisture barrier beneath it.
Allow wood to reach equilibrium before finishing.
- Allow the hardwood to reach the moisture content under which it will be in service Delay sanding and finishing the hardwood until it reaches its equilibrium. Break hardwood material down into small lots, and store the lots in the rooms in which they will be installed. You may need to allow four to five days for the flooring to become acclimatized to the moisture conditions in the house as shown in Figure 35.
