How to Build Support Beams

Written by randall bullard
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How to Build Support Beams
2 inch by 12 inch support beam with joist attached.

Building support beams is one of the easier aspects of building a home. Although there are certain criteria that need to be met for support beams in relation to the load that is being supported, the actual building of the support beams is a task any handyman can complete.

Skill level:

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Things you need

  • Set of saw horses
  • Circular saw
  • Extension cord
  • Tape measure
  • Pencil
  • Speed square
  • Hammer
  • 12 penny nails
  • 1/2 inch thick plywood
  • 2 inch by 4 inch dimensional lumber
  • 2 inch by 6 inch dimensional lumber
  • 2 inch by 8 inch dimensional lumber
  • 2 inch by 10 inch dimensional lumber
  • 2 inch by 12 inch dimensional lumber

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  1. 1

    Measure the length where the support beam is needed. Consult a building chart to determine the proper dimensional lumber that is needed to cover the distance. Buy the dimensional lumber from a building supply house to build the beams.

  2. 2

    Set up the saw horses. Get the circular saw and extension cord set up. Place the sheet of plywood on the saw horses. Cut the plywood in 8-foot strips 1/4 inch narrower than the width of the appropriate lumber for the beams.

  3. 3

    Place the appropriate dimensional lumber for the beams on the sawhorses. For each beam use the tape measure to measure the dimensional lumber the required length. Mark the length with a V pointing to the position of the saw line. Use the speed square to draw a straight line across the width of the lumber. Cut the lumber for the beams.

    How to Build Support Beams
    2 inch by 12 inch support beam with joist attached.
  4. 4

    Cut the 8-foot plywood strips 1/4 inch shorter than the two boards for the support beam. Place one of the boards for the beam flat on the saw horse. Place the plywood strip on the board for the beam. Lay the other board for the beam on top of the plywood. Remember to stagger the joints in the support beam so that they fall closely to where the support posts will be.

  5. 5

    Make sure that the ends and sides of the boards are flush The plywood should not protrude from within the centre of the boards for the beam. Begin at one end of the beam and nail the boards together using the 12 penny nails and hammer. The nails should be driven into the wood in an alternating V pattern. Flip the beam over. Nail the boards from the other side using the same V shaped pattern. The beam is complete and ready for installation.

Tips and warnings

  • For distances that are greater than 7 feet between support posts use Laminated Veneer Lumber (LVL), glued-laminated timber (glulam) or appropriate engineered wood-products.
  • Always consult local building codes to ensure compliance. Use beams of adequate thickness for support. Improperly sizing beams that bear a load can be dangerous to the structural integrity of a building. Depending on the dimensional lumber being used the distance between supports is affected by the weight it supports. Use adequate support posts spaced appropriately to support the load.

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