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Multi-Story Wood Frame Construction and Exterior Metal Cladding

Multi-Story-Wood-Framing-Metal-Cladding-Walls-Shrinkage-Compression-(2).jpgWood Framing Considerations:
  • Increased potential for high moisture content
  • Specs and industry recommendation often specify a maximum of 19%
  • Lumber drying from 19% to 10% can result in approximately 1” of shrinkage in a four-story wood framed building (WWPA*, 2002)
  • Non-protected lumber (inadequate site storage) can result in moisture content much greater than 19% (two days of rain wetting can increase moisture content of 50% or more)
  • Shrinkage/compression values of materials at floor plates due to construction tolerances and shrinkage of members
  • Allowances for shrinkage and compression of framing

Viable Recommendations for Wood Framing Considerations:
  • Create control joints at floor lines
  • Create control joints at secondary framing members
  • Pre-notching of trim and flashing allows for metal expansion and wood shrinkage/compression
  • Pre-slotting/drilling of panels at fastener locations
  • Do not bridge floor levels with flashing (overlaps are recommended at floor locations)
  • Allow for additional gap values at flashing connections to allow for metal expansion  as well as framing shrinkage