Fit the wood to the space

• 1
  Wood paneling lends warmth to a room or porch.The surface-treated natural wood boards image by Supertrooper from Fotolia.com
  
  If the space to be covered is rectangular, begin at the highest point. If it is angled, begin at the widest point.
  
  
• 2). Cut the wood to fit the space to be covered, pointing the tongue of the plank outward, where the next piece of wood will be going.
  
  
• 3). Nail the first board on by driving two nails through the board and into each rafter, one at the beginning point against the wall and the other through the tongue at a diagonal, so that it passes through the board and into the rafter.
  
  

Apply boards across the width of the ceiling

• 1). If the area to be covered is triangular or irregular, custom cut each board. If the area is square or rectangular, you may be able to cut them all to the same length.
  
  
• 2). Drive the groove of each board onto the tongue of the previous one. If the board is slightly warped, press a chisel tight against the face of the tongue, drive the point of the chisel into the rafter, pry the board tight against the previous board, and nail it. If a board is too badly warped, you may have to cut it where it meets a rafter and nail it up as two separate boards, thus removing most of the warp.
  
  
• 3). You'll probably have to custom cut the last board to fill the last space next to the wall. Don't assume that this space is the same width on both ends. Measure it precisely, and if necessary cut the final board at different widths at each end to fill the space tightly.
  
  

Add trim and finishing

• 1). If the joints at the ends or sides of the tongue and groove boards are too large or uneven, apply quarter round or cove molding to cover the gaps. Cut the molding to the length needed and nail it to the side walls, up as tight against the ceiling boards as possible.
  
  
• 2). Use finish nails rather than large-head nails for the ceiling boards and trim. This will make for a neater, more finished appearance. Lightly sand all of the boards and the trim with 100 grit sandpaper, rubbing the sandpaper along the grain rather than across it.
  
  
• 3). Finish the installed wood with stain, linseed oil or polyurethane. Linseed oil will darken over time and give the wood a deeper, rich appearance.