How to Construct Loft Railings

• 1

  Cut 4-by-4-inch posts to 42-inch lengths, assuming the floor joists are 6-inches. Otherwise, cut the posts to 36-inches plus the height of the floor joists.

• 2

  Drill two 1/2-inch diameter pilot holes, one about 1 inch from the bottom of the post and the second hole 3 inches above the first hole. Drill all the way through the posts.

• 3

  Drill 1/2-inch diameter pilot holes, 1-1/2-inches deep, into the floor joists so the holes line up with the holes in the posts. Each set of holes in the floor joists is spaced 6-feet on center.

• 4

  Mount the posts to the outside of the floor joists, spaced 6-feet on center. Insert a 6-inch long, 3/4-inch diameter lag bolt into each pilot hole and tighten with a ratchet wrench.

Assembling Railing Sections

• 5

  Cut all the 2-by-4-inch lumber pieces required for each section of railing; you'll need to construct one section for each gap between posts. Each section requires two 68-inch pieces.

• 6

  Cut the pieces of 1-by-4-inch lumber required for each section of railing. This requires eight 30-inch pieces.

• 7

  Set the two 2-by-4 pieces horizontally on a flat surface, spaced 30 inches apart, with the wide side facing up. There should be 30 inches from the top of one board to the bottom of the second board.

• 8

  Lay the 1-by-4 inch pieces on top of the 2-by-4s, running vertically. Space the boards evenly so there is a 4-inch gap between each board and 4-inches in from the ends of the 2-by-4s.

• 9

  Attach the 1-by-4s to the 2-by-4s with 2-1/2-inch wood screws; use one screw for the top and one for the bottom. Each screw goes straight through the 1-by-4 and halfway through the 2-by-4 to ensure a strong hold.

Assembling the Railings

• 10

  Hold one section of railing in place between two of the 4-by-4-inch posts. The railing must be 4-inches up from the floor and the ends of the 2-by-4s butt up against the posts. Set scrap pieces of 4-by-4 on the floor to make it easy to achieve and maintain the proper height.

• 11

  Drive 4-inch wood screws at an angle through the 2-by-4s and into the posts. It is necessary to have a second person hold the railing in place while screws are inserted. Insert a screw through the top and bottom of each 2-by-4 for added strength.

• 12

  Set a 2-by-4 on top of the railings, with the 4-inch side facing up, after each section is installed; attach with 4-inch wood screws inserted through the top and into the top 2-by-4 of the railings. When the length of the railings is longer than your 2-by-4-inch lumber, join two pieces with a 45-degree miter cut to produce a smooth seam. This step is optional, but creates a comfortable handrail that gives the loft railings a finished look.