How to Reinforce a Sagging Shelf

Three Methods:Shelf Reinforcement Method #1Shelf Reinforcement Method #2Shelf Reinforcement Method #3

Shelves are designed to hold objects. The more objects placed on a shelf, the more weight that shelf must bear. Too much weight coupled with a flimsy construction can lead to sagging in the middle of the shelf. Sagging is unappealing, but it is also a potential hazard. If the shelf breaks due to stress, the objects on the shelf might also break and harm you or someone else. Use these steps to reinforce your sagging shelf.

Method 1
Shelf Reinforcement Method #1

  1. 1
    Measure the length of the sagging shelf to determine the center point.
  2. 2
    Calculate the distance between the shelves parallel to the sagging layer.
  3. 3
    Purchase a metal shelving bracket that fits the distance between shelves.
    • If your hardware store does not have the correct size, buy a longer bracket and cut it to fit.
  4. 4
    Place the metal bracket in the center of the shelf and line it up with the center of the shelf below it.
  5. 5
    Mark the center of each shelf with a pencil.
  6. 6
    Remove the sagging shelf and the shelf immediately below it.
  7. 7
    Screw drywall anchors into the marked spots on the shelves.
  8. 8
    Position the brackets over the anchors.
  9. 9
    Plant screws into the anchors, making sure the fit is tight.
  10. 10
    Replace the shelves.

Method 2
Shelf Reinforcement Method #2

  1. 1
    Measure the sagging shelf to find the midpoint and mark that point with a pencil or piece of tape.
  2. 2
    Determine the distance between shelves (height) and write that exact number down.
  3. 3
    Measure the depth of the sagging shelf and write that number next to the height.
  4. 4
    Obtain a 3/4 inch (1.9 cm) plywood plank.
  5. 5
    Use a table saw to cut the plank to the correct height and depth.
  6. 6
    Sand the wood with fine-grit sandpaper.
  7. 7
    Apply polyurethane or wood finish to the plank to match the color and finish of your shelving unit.
    • If you are using this technique for a non-wood structure, you can skip this step or paint the wood to match your particular shelf.
  8. 8
    Place the vertical divider onto the midpoint of the shelf as if you were replacing a book.
  9. 9
    Nail the divider into place from the top and bottom.

Method 3
Shelf Reinforcement Method #3

  1. 1
    Measure the length and width of your sagging shelf.
  2. 2
    Obtain a piece of lumber larger than the shelf.
  3. 3
    Use a table saw to cut off the extra wood.
  4. 4
    Apply wood glue to the top of the wood.
  5. 5
    Place the reinforcement wood under the sagging shelf.
  6. 6
    Clamp the shelf to the new piece of wood.


  • To disguise your vertical divider, cover it with an old book sleeve. It will look like another book on your shelf.
  • You can add more than one metal shelving bracket if more reinforcement is needed.
  • The thicker the plywood used to reinforce your shelves; the more weight the shelf will be able to hold without sagging.


  • Do not overfill shelves with heavy objects, even if the shelf is stiffly reinforced.
  • Make sure the drill bit you use to create holes in the metal shelving unit match the drywall anchors and screws you use. Using smaller screws will prevent sturdiness.

Things You'll Need

  • Measuring tape
  • Metal shelving bracket
  • Pencil
  • Paper
  • Drywall anchors
  • Screws
  • Drill
  • 3/4 inch plywood plank
  • Table saw
  • Sandpaper
  • Nails
  • Wood glue
  • Clamp
  • Hammer

Article Info

Categories: Furniture and Cabinets