Box car siding is a term used to describe any of several varieties of 1-by-6 and 1-by-8 pine tongue and groove siding products. Some are smooth, while others feature "beadboard" style detail lines down the center and slightly rounded edges. The installation procedure for all of these materials is essentially the same and follows a pattern similar to install tongue and groove siding or flooring in other applications. One major distinction between box car siding and newer types of tongue and groove is the absence of end joints, common in hardwood floor materials. Ends are usually butted up to the piece before for a clean, simple joint that is supported by staggering the end joints from row to row.
Use a pry bar to remove any crown molding around your ceiling. Use locking pliers to pull the nails through the rear of the molding to preserve the face and set it aside to be reinstalled.
Turn off the power to any light fixtures on the ceiling where the paneling will be installed at the circuit breaker. Remove the screws mounting the fixture to the junction box and twist off the wire nuts to disconnect the wiring. Set the fixture aside to be reinstalled. Also remove ceiling vents grilles and other obstructions.
Use a stud finder to locate the ceiling joists above your ceiling. Depress the buttons on both sides of the device and run it along the ceiling parallel to the longest wall. Mark every spot the finder beeps and flashes, indicating the presence of a framing member. Do the same along the opposite wall. Use a chalk line to mark the length of the joists from the marks on one side to the marks on the other. The lines will be 24 inches apart. In some newer construction, they may be 16 inches apart.
Start installation along the longest wall in the space. Position a full length lank of siding, spaced 1/4 inch from the wall, with the tongue side out and the groove toward the wall. Space the end 1/4 inch from the wall at the corner. Drive a 2 inches long finish head screw up through the siding into the first joist, as indicated by the chalk line, out from the wall. Drive one screw up through the siding into each joist. Drive the screws in until the heads are just past the face of the siding.
Butt the next piece up to the open end of the first and screw it against the ceiling in the same way. Add one screw into each joist down the length of the board. Continue adding full length planks as far as possible. Measure and cut a plank to fit from the last full piece to 1/4 inch from the far wall and screw it into place.
Start the second row using the off-cut piece from the end of the first row. This will space the joints between the ends of the boards to stagger them between rows. Fit the plank with its grooved edge against the tongue on the outside edge of the first row. Tap the board up snug to the first row with a wood block and hammer so that the groove covers the tongue. Screw the plank into place as in the first row.
Add planks, butting them up to the one before as you did in the first row. Cut a piece to fit at the wall as you did before. Continue adding full width rows of siding across the ceiling as far as possible. Measure and cut pieces to fit around light fixtures junctions and other obstructions with a jig saw.
Measure from the last full row to the wall and cut enough siding to width to fill the gap, leaving 1/4 inch against the wall. Screw the last row in place as before. Realign the crown molding to the wall and nail it in place with a pin nail gun -- one nail every 8 inches -- to cover the gap next to the wall.
Match the wires by color and replace the wire nuts on your light fixtures to reconnect them. Use longer mounting screws if needed and reattach the fixture to the junction box. Use longer screws for any vent grilles as well.