DIY Storage: Spans and Loads

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Shelving shouldn’t sag or bend under the weight of a load. The guidelines and chart below will help you select the appropriate materials for your project. Note that there are a number of ways to deal with a too-heavy load: you can reinforce the shelf, change the material you construct it of, choose a thicker or wider piece of stock, or shorten the span. The general guideline is: the thinner, the narrower in width, and the longer the piece of stock, the more apt it is to bend.


Lumber: is the most rigid material and therefore least apt to bend under loads.

Plywood: is less rigid than lumber and thus more apt to bend.

Particle board and hardboard: are least rigid and are thus apt to bend or even break under loads.

Load Types

In designing a shelf, consider not only the weight (load) but also how it will be distributed, and select a shelf design, a construction method, and materials that have sufficient rigidity to avoid sagging. The potential for sagging will vary with the way the load is placed on the shelf.

Ways to Reinforce a Sagging Shelf

Be conservative in deciding the length of shelf spans; if there is a possibility of sagging, use one of the reinforcing methods shown here.

Apply lumber to one or both long edges.

Add mid-span supports as needed.

Add support around shelf edges.

Table below shows: Load Capacities

Light Load -- yellow dot -- (10 - 15 pounds. Example: towels.)

Average load -- black dot -- (15 to 25 pounds. Example: mix of canned and boxed food staples.)

Heavy load -- red triangle -- (25 to 50 pounds. Example: LPs, LaserDiscs, Books).)

Reinforce -- R -- (You’ll need to reinforce a shelf of these dimensions.)

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ALL ARTICLES in this Guide:

DIY and Custom-Made Storage Solutions: Components You Can Build for Home, Office ... as a Hobby or for Sale (Profit, earn Income)

  1. Storage Components
    1. Shelves
    2. Pockets
    3. Dividers
    4. Modules
    5. Rollouts
    6. Cases and Chests
    7. Tops, Doors, and Toes
    8. Racks
  2. Tools, Techniques, and Tips
    1. Materials
    2. Spans and Loads
    3. Sizing Up Your Space
    4. Layout and Cutting List
    5. Cuts and Joints
    6. Detail Milling and Edging
    7. Drilling and Fastening
    8. Gluing, Clamping, and Assembly
    9. Doors and Drawers
    10. Face Frames and Miter Boxes
    11. Hardware
    12. Finishing

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Modified: Monday, 2010-08-23 23:38 PST