Reinforcing Floor Joists With Holes Through Them

Whenever a floor joist has a hole through it, whether the hole is the result of a pipe passing through or a loose knot, the joist is weakened. The closer the hole is to the bottom of the joist, the more impact it has on the joist strength. Reinforcing a joist that has a hole through it before it develops problems will save you the trouble of having to repair more serious damage in the future.

Measuring tape
2-by-8 lumber
Construction adhesive
Screws, 4 inches long
Drill
Circular saw

Instructions

- 1
  Remove any pipes or other objects that are passing through the joist if they are no longer serving any purpose.
- 2
  Cut two pieces of 2-by-8 lumber to a length of 3 or 4 feet, or as long as is reasonable within the space where you are working. The longer the pieces are, the stronger your reinforcement will be.
- 3
  Spread construction adhesive onto one face of each of the pieces of 2-by-8.
- 4
  Place one of the 2-by-8s against the side of the joist so that the hole in the joist is in the center of the length of the 2-by-8.
- 5
  Screw the 2-by-8 onto the joist using a 4 inch screw at each end. Only drive the screws in far enough to hold the 2-by-8 in place.
- 6
  Place the other 2-by-8 opposite the first one so that the joist is sandwiched between the two 2-by-8s. Screw this 2-by-8 onto the joist with 4 inch screws, driving the screws all the way through the 2-by-8, through the joist, and into the opposite 2-by-8.
- 7
  Drive the first two, 4-inch-long screws that you put into the first 2-by-8 all the way in so that they go through the joist and into the opposite 2-by-8.
- 8
  Add more 4-inch-long screws to both 2-by-8s. The more screws you put in, the stronger the reinforcement will be.

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