Remove any baseboard molding around the room.
Set a laser level to the desired height of the wainscoting (this project was 53-1/2 inches) so everything is nice and level. Measure from the laser line to where the base plate will fit, based on the height of the siding boards. Any imperfections in the floor will be covered later by the base molding.
Based on these measurements, mark the wall with a piece of chalk where the top of the MDF baseboard will be attached.
Rip the MDF into strips 5-1/2 inches wide. Cut the strips lengthwise to fit around the base of the room. Wherever the strips meet along the straight part of the wall, cut the seams of the scarf so the pieces match up and hide the seam. One piece should be cut at a 15 degree angle to the front and the complementary angle to the back. Join the pieces at the corners with 45 degree angles.
Attach the strips to the wall with 2" nails.
Cut the 4 x 8 sheets of wainscoting in half.
If there are exposed electrical outlets or wires or telephone jacks, measure and mark the location on the piece of siding for cutting. Using a drill that is large enough to fit a hacksaw blade, drill a hole in the edge of the area to be removed. Make sure to drill inside the mark, then cut around the marked area with a jigsaw, starting at the drilled hole.
Liberally apply construction adhesive to the back of a siding panel and hold it against the wall so that the bead runs vertically.
Lay the liner on the wall with the bottom resting on the MDF strips that were added at the base. Quickly remove the panels from the part of the wall out of the way so that the adhesive becomes stringy and covers more area on the back.
Quickly nail down the siding with 2-inch pointed nails to hold it flat against the wall and prevent it from shifting.
Unless the perimeter measurement of the room is divisible by four, then a siding panel will need to be cut to fill in smaller gaps.
After siding is applied, attach the base trim to the exterior of the MDF at the base with 2-inch brad nails. Make sure the trim also has scarf joints to hide the seams.
Lastly, add a chair rail to the top of the siding, using the same gouging and glove nailing technique as the siding and trim.
