While the use of brick veneer supported by Metal Plate Connected Wood Trusses (MPCWT) is not covered by the prescriptive methods of either the International Building Code (IBC) or the IRC, code compliant use of MPCWT to support brick veneer can be accomplished and can be applied to many different situations utilizing MPCWT’s. This guide focuses specifically on creating a code compliant connection where exterior masonry veneer is located on the gable end at the transition from a wider section of a building to a narrower section.

Step-by-Step: 

Intro

Introduction

  • The IRC 2015 includes no prescriptive provisions to specifically address an exterior brick veneer wall supported directly by MPCWT
  • Code compliance can be accomplished by both individual designs and by adhering to the guidance in this presentation

  • This presentation specifically focuses on masonry veneer supported by MPCWT on the gable end at the transition from a wider section of a building to a narrower section
  • However, the concepts shown can be applied to many different situations utilizing trusses

Step 1

Review Detail

 

  • The detail below may be referred to by the building designer to achieve a code-conforming steel lintel connection

  • Section view
  • Note that sheathing must be covered with a water-resistant membrane, unless the sheathing is water resistant and the joints are sealed.

Alternative Details

 

  • An alternative connection using (3) 2x6’s to support the brick masonry veneer directly above the 2x6’s

    

  • Another alternative connection using (3) 2x6’s to support the brick masonry veneer:

  • An alternative connection using 2-ply MPCWT directly below to support the brick masonry veneer:

  • An alternative connection using 2x_ material between MPCWT to support the brick masonry veneer:

Step 2

Verify Design Values

  • Truss total load deflection is limited to L/600
  • Load Duration factor is CD=0.9
  • Creep factor for long-term deflection calculation shall be 1.5 for dry lumber and 2.0 for unseasoned lumber
    • Creep is defined as time-dependent deformation of a structural member under constant load. In this case brick dead load is a constant and/or sustained load (see ANSI/TPI 1-2002, 2007)
  • Maximum weight of brick masonry veneer is 40 psf
  • Maximum height of brick masonry is 12’-8” per the IRC

Step 3

Select Lintel

 

  • A minimum 6” x 4” x 5/16” (152 mm by 102 mm by 8 mm) steel angle, with the long leg placed vertically, shall be anchored to MPCWT using bolts per the following tables.
  • For assemblies with Structural Sheathing:

  • For assemblies with Non-structural Sheathing:

Step 4

Determine if Stops are Needed

  • The maximum slope of the roof construction without stops welded to the steel angle shall be 7:12
  • Trusses supporting veneer with slopes between 7:12 and 12:12 shall have stops of a minimum 3” x 3” x ¼” (76 mm x76 mm x 6 mm) steel plates welded to the angle at max. 24” (610 mm) o.c. along the angle or as approved by the building official

Step 5

Select Ties

  • Stainless steel ties specified under ASTM A 240 or A 580
  • Corrosion protected ties such as zinc coated corrugated steel ties, minimum 22 U.S. gauge thick (0.0299”), 7/8” x 6” (0.76mm x 22 mm x 152 mm) complying with ASTM A 653 and A 153 class B2

  • Strand wire ties are less susceptible to corrosion than corrugated steel sheet ties
  • Minimum strand wire size diameter shall be 9 U.S. gauge [(0.148”) or (4 mm)] and be spaced same as corrugated steel ties and shall have a hook embedded in the mortar joint

Step 6

Select Tie Spacing

  • Veneer ties shall be spaced at maximum 32” o.c. (610 mm) horizontally and 24” o.c. vertically and shall support max 2.67 ft^2 (0.25 m^2) of brick veneer wall area
  • For new construction, wall stud spacing of 16” o.c. is recommended so that ties can be anchored at this spacing

  • The following tables provides recommendations for maximum vertical tie spacing for high wind areas when structural gable truss vertical members are spaced at 24”, 16” and 12” on center spacing
  • In the areas that are susceptible to both high wind and seismic loads, masonry brick veneer system should be evaluated by an RDP to ensure that brick veneer cladding can resist both seismic and wind design loads
  • Maximum vertical tie spacing for assemblies with structural sheathing

  • Maximum vertical tie spacing for assemblies with non-structural sheathing

Step 7

Flashing and Weep Holes

Flashing and Weep Holes

  • Flashing and weep holes shall be located in the brick veneer wythe above the steel angle
  • Flashing below the steel lintel should consist of normal step flashing and counter flashing installed directly on the adjacent (i.e., lower) roof sheathing including weep holes at maximum 33” o.c.

Step 8

Vertical Expansion Joints

  • Create vertical expansion joints @ a maximum 25’ (7.6 m) o.c.

  • The actual location of vertical expansion joints in a structure depends on the structural configuration as well as the expected amount of horizontal movement
  • Expansion joints are typically sized similar to a mortar joint, usually between 3/8” and 1/2”

  • Vertical expansion joints should also be considered with:
    • Corners
    • Offsets
    • Setbacks
    • Wall intersections
    • Changes in the wall height
    • Brick veneer support changes
    • Wall function or climatic exposure changes