Viewing 2 reply threads
  • Author
    • #74160

      does anyone know if it is ok to use a triple 2×12 beam to span 12 feet in a basement? there is 4 1/2 inches of bearing on each end of the beam. the floor joist are 16 inch center 2×8 and only about 10 feet long. house is a bilevel. looks like the bearing wall was taken down and replaced with 3 2×12. everything is screwed together. any info would be helpfull.

    • #303179

      The supported floor is 120 square feet of living space. 2×8 joists 16-inch on center at 10 feet of span and terminated and blocked on the beam, is a conservative sizing appropriate for living space and a deflection value of less than 360 and live load of 40+ psi.

      You effectively have a field constructed beam 3-2×12 (6×12 nominal) over a 12-foot distance, which is correct for that span in most framing, even as a central beam (technically this could carry twice the floor span). The unknown question is how does that transfer weight to the ground? If the beam directly ties to the foundation, and transfers load to the footer, its very unlikely to fail. I am not a structural engineer, and having your plan reviewed by one is the best idea.

    • #303180

      According to the engineering tables, this section is undersized if used as an interior girder.

      2 2x12s can only span a maximum distance of 7 feet when support 1 floor and the building width is 28 feet.

      Not even 3 2x12s can span this distance. The maximum span for 3 2x12s is only 8′ 10″ for a builidng 28 feet wide.

      You would need a minimum a 4 2x12s to span 10ft if this span is part of the middle beam and the width of the house is 28 feet.

Viewing 2 reply threads
  • You must be logged in to reply to this topic.