Use of Connectors and Brackets Home Builder’s Guide to Coastal Construction FEMA 499/June 2005 Technical Fact Sheet No. 17 Purpose: To highlight important building connections and illustrate the proper use of various types of connection hardware. Key Issues --In high-wind regions, special hardware is used for most framing connections. Toe-nailing is not an acceptable method for resisting uplift loads in high-wind regions. --Hardware must be installed according to the manufacturer’s or engineer’s specifications. --The correct number of the specified fasteners (length and diameter) must be used with connection hardware. --Avoid cross-grain tension in connections. --Metal hardware must be adequately protected from corrosion (see NFIP Technical Bulletin 8-96). --Connections must provide a continuous load path (see Fact Sheet No. 10). [Graphic -- Detail #1] Proper fasteners must be used with connection hardware. Fill all nail holes with specified fasteners, unless reduced nailing is specified by design. The length and diameter of the fasteners must be as specified by the manufacturer or engineer; some specifications require non-standard nails. [Graphic -- Detail #2] Avoid load path failure at roof-to-wall connections. Improper connection to only one member of top place can lead to failure under uplift loads. Instead, nail connector to outside face of both top plate members, or nail to stud and top plate members. [Graphic -- Detail #3] Proper bracket connection. Offset bracket vertically to achieve minimum specified end spacing for bolts. Bolt, screw, or nail diameter and quantity as specified. Material to which bracket is attached must have adequate thickness for maximum bracket capacity. [Graphic -- Detail #4 Truss Member Connections] Truss member connections are made with metal plates that connect the individual parts of a truss to form a structural component. Every joint must have a connector plate on each face sized and positioned according to engineered designs. Plates must be fully embedded, and gaps at joints should be minimized (see ANSI/TPI-1 95). [Graphic -- Detail #5 Truss-to-Truss and Rafter-to-Truss Connections] Truss-to-Truss and Rafter-to-Truss Connections are made with metal hangers specified by the truss designer. [Graphic -- Detail #6 Roof-to-Wall Connections] Roof-to-Wall Connections are made with metal rafter ties or straps, sometimes referred to as hurricane straps. These connectors replace toe-nailing and provide added uplift resistance. The strap should extend above the centerline of the rafter or, for the strongest connection, completely over the rafter. Important Coastal environments are conducive to rapid corrosion of metals. All connection hardware must be properly protected. Galvanized coatings on readily available hardware may not be adequate or in compliance with local coastal building codes. Special-ordered hardware, re-galvanizing, field-applied coatings, or stainless steel may be required. [Graphic -- Detail #7 Stud to Top Plate] Stud-to-Top-Plate Connections are made with metal straps, nailed to the side and/or face of the stud and the top of the top plate. These connections replace toe-nailing or end-nailing and provide added uplift resistance. The strap should wrap over the top plate. [Graphic -- Detail #8 Floor to Floor] Stud-to-Stud Connections are made with nailed metal straps, or brackets with threaded rods, that connect one story to the next. [Graphic -- Detail #9 Window Header] Header Connections are made with nailed straps. They transfer accumulated uplift loads from the header to the jack studs. The straps should extend the full depth of header. [Graphic -- Detail #10 Beam to Joist] Joist-to-Beam Connections are made with ties similar to roof-to-wall connections or with wood blocking. [Graphic -- Detail #11 Foundation Anchor] Wall-to-Foundation Connections are made with metal brackets or bolts that connect wall studs and/or sill plates to foundation walls, beams, or band joists. [Graphic -- Detail #12 Rod Connection] Continuous Rod Connections are made with a system of threaded rods, couplings, and brackets. These connections can be used to tie the roof and walls to band joists and support beams. [Graphic -- Detail #13 Pile to Beam] Pile Connections are made with special brackets, spiked grids, bolts, or other types of connectors that attach the main floor beams to the piles. It is extremely important to follow design specifications for this connection (see Fact Sheet No. 13 for further details). Important These are examples of typical connectors used in residential construction. For the required continuous load path to be maintained, all connectors used must be adequate to resist the loads expected to act on them. Stronger connectors may be necessary to areas subject to high winds or earthquakes. Additional Resources American National Standards Institute. National Design Standard for Metal Plate Connected Timber Trusses, ANSI/TPI-1 95. [End of Fact Sheet No. 17]