How to Sister a Floor Joist: Repairing Sagging or Damaged Joists
Sistering a floor joist strengthens a sagging or damaged span by adding a matching joist beside the existing one, effectively doubling cross-section for better load transfer. Start by inspecting for rot, cracks, or insect damage, then temporarily shore and align the new joist with the existing, keeping depth and spacing consistent. Attach with through-bolts or…
