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Load Transfer Mechanism Explanation

0:37
1:53
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Why we stopped ballon framing 👍 #carpentry #framing #codes #building #learn

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What happens here

The presenter uses a whiteboard diagram to further explain the load transfer mechanisms in both platform and balloon framing. For platform framing, he illustrates how the 'floor load' from the 'second floor' transfers down through the 'joist' and 'subfloor' to the 'double top plate' and then directly into the 'stud wall' below, indicating that no fasteners are heavily relied upon to carry the vertical load. In contrast, for balloon framing, the diagram shows the 'floor load' traveling through the 'joist' and then relying on 'nails' and a 'ledger board' (which is inset into the stud wall) to transfer the load down the continuous studs. He clarifies that ledgers are common in other structures like decks, but ledger failure in balloon framing can lead to total floor collapse.

Goal: Understand how floor loads are handled differently in each framing type.

Tools and materials

  • Dry Erase Marker N/A — Drawing diagrams on the whiteboard
  • Pointer Stick N/A — Highlighting parts of the diagram
  • Whiteboard N/A — Illustrating framing diagrams and load paths

What they say

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the load. Platform framing is done in sections. The joist and subfloor split these two walls. As you get floor load, the weight goes down into your joist, travels across, and will go fully down the stud wall. This does not count on nails or fasteners to hold your floor weight. For balloon framed, it's common that a ledger board would get inset into the stud wall. This ledger being recessed in the stud wall was not always the case. So, as your floor load goes through your joist and comes down your stud wall, it counts on these fasteners and this ledger to handle the floor weight. It's often thought that this is the main issue with balloon framing, but it isn't. Ledgers are still used on decks, pole barns, and other structures. Also, a ledger failure could allow the entire floor to collapse at once. For example,

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