How to Add Wood Supports to Wooden Staircases With Decay

Taking Staircase Measurements

• 1

  Measure the distance from the staircase to the ground from the midpoint, using a tape measure. The midpoint is the location at the exact middle of the staircase's ascent from the bottom step to the top. Record the measurement on a piece of paper. Note the angle of staircase, using your angle finder. Record the angle on a piece of paper.

• 2

  Measure the width of the staircase at the midpoint, using the tape measure. Begin the measurement at the left stringer and finish at the right stringer. A stringer is the long piece of wood cut to receive treads running along both sides of the staircase. Record the width of the staircase from stringer to stringer on a piece of paper.

• 3

  Purchase two 6-by-6-inch wooden posts cut to the height of the measurement taken from step one. Purchase three 2-by-6-inch wooden boards cut to the width measurement taken from step two.

Building Support Brace

• 4

  Draw an angled line using a pencil on the top of each 6-by-6-inch wooden post to match the angle of the staircase. Repeat step one from section one to ensure the angle and height are correct. Cut the tip of each wooden post to match the angle, using a handheld circular saw. Posts should fit snugly underneath each stringer in the upright position at the staircase's midpoint.

• 5

  Fix the two posts to the midpoint of the staircase stringers, using the two steel timber-frame brackets. Using a cordless drill, attach the steel timber-frame brackets to the wooden posts and the staircase stringers using 16 Frearson flat head wood screws. Four screws connect each bracket to the wooden posts and the staircase stringers.

• 6

  Use a racheting wrench to fix two 1 1/2-inch carriage bolts to a steel L bracket at the bottom of the left wooden post. One carriage bolt connects the L bracket to the post; the other connects the bracket to the floor. Repeat this process on the right wooden post.

• 7

  Connect the two wooden posts by attaching one 2-by-6-inch wooden board to the top where the posts meet the staircase. Using the cordless drill, drive four Frearson flat head screws into each end of the board to connect it to the wooden posts.

• 8

  Attach the two remaining 2-by-6-inch wooden boards to the posts in an X pattern beneath the connecting board at the top. Use four Frearson flat head wood screws in a square pattern to connect the boards at each end with your cordless drill. Where the two boards meet, drive a Frearson flat head wood screw with your cordless drill to connect them. Using your handheld circular saw, remove any excess wood hanging from the completed brace.