How to Support a 32-Foot Sagging Wood Beam

Wood beams can sag if they are undersized for the weight they must carry or the distance they must span. They can sag if damaged by exposure to water, fire or termites. Sagging is an aesthetic problem, but more importantly, it is a serious indication of ongoing structural failure.Wood beams of less than 20 feet can usually be repaired by anyone with an understanding of residential carpentry. Contact a licensed structural engineer to recommend repairs for beams longer than 20 feet. After inspections and calculations, the engineer will recommend replacement of the beam, reinforcement of the beam or adding intermediate columns to support the sag. These recommendations should be summarized in a structural engineer's report.

How to Support a 32-Foot Sagging Wood Beam

Wood beams

Remove all furnishings, storage or miscellaneous items from the floor that the sagging beam supports. If the beam supports a roof, remove snow and any unattached items on the roof to reduce as much weight from the beam as possible.

Use the tape measure to mark locations recommended by the structural engineer to install adjustable steel columns to support the sagging beam.

Move the adjustable steel columns to their recommended locations. Hand-tighten the top support plate to gently hold the column in place. Use a level to straighten each column to a perpendicular position.

Nail each adjustable column's base and top plates in place. The structural engineer's recommendations will include the number and length of nails and horizontal bracing, if required.

Tighten and raise each adjustable top plate as recommended by the structural engineer. Do not reduce the depth of the beam's sag, or attempt to level the floor, without specific instructions from the engineer.

Replace items removed from the floor or roof above the beam prior to installation of the columns.

Things You Will Need

  • Structural engineer's report
  • Tape measure
  • Adjustable steel columns
  • Level
  • Hammer
  • Nails


  • Check your local building code's requirements before you start. Some code administrators will request to see your structural engineer's calculations.


  • Adding support to a 32-foot long sagging wood beam is not a DIY project unless you are a structural engineer. The condition and structural capability of the floor supporting the adjustable steel columns are as important to understand as the condition of the beam itself.

About the Author

Gregory Jenkins earned his B.S. in Architecture from the University of Cincinnati in 1971. Technical writing has been an integral part of his 30-year construction career. His interests have recently expanded to include architectural history, and preservation, and he is the author of a weekly blog featuring landmarks in Chicago and the the newly published book "Chicago Figural Sculpture, A Chronological History."

Photo Credits

  • construction - o1 image by samantha grandy from Fotolia.com