How to Make Structural Repairs by Sistering Floor Joists

Repair sagging or broken floor joists by “sistering” on a new joist

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Hammer
  • Tape measure
  • Circular saw
  • Caulk gun
  • Hearing protection
  • Safety glasses

You may also need a corded drill and bits for predrilling holes if the joists are old and hard, and nailing is difficult.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • 16d common nails
  • Joists
  • Construction adhesive
  • Hydraulic jack