How to Install the WonderBoard With Either Side Out
- 1). Measure the area on the floor where you will be installing the Wonderboard with a tape measure. Multiply the length by the width of the room to get the total square footage. Divide that number by 15, which is the square footage of a piece of Wonderboard to get the number of sheets necessary for installation.
- 2). Open up a tub of thin-set mortar and dip a notched trowel into the mortar. Spread out the mortar over the subflooring, beginning at any corner of the room. Cover a space on the flooring with a thin, even layer of thin-set mortar big enough for the first 3-by-5 foot sheet of Wonderboard to sit on.
- 3). Set the first piece of Wonderboard down with either side facing out perpendicular to the subflooring underneath and leave a gap of 1/8-inch between the panel and the edge of the wall. Run your hands over the entire surface so the Wonderboard can adhere to the flooring underneath.
- 4). Fasten the Wonderboard down with 1 1/4-inch backerboard screws. Position the screws every 8 inches around all of the board, and at least 1/2-inch from the edge of the board. Continue installing screws around the perimeter of the first board with a power drill. Spread out mortar where the second piece will go just like the mortar was applied for the first piece.
- 5). Set the second piece of Wonderboard down next to the first and leave a gap of 1/8 inch to allow for expansion. Continue installing the remaining Wonderboard just like the previous pieces were installed until you reach the end of the first side.
- 6). Measure and mark the final piece of the first side with a black marker. Line up a T-square along the mark and score the Wonderboard with a utility knife multiple times until the Wonderboard snaps in two. Install the cut piece just like the previous pieces were installed.
