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Wood Construction Connectors General Instructions for the Installer

Technical & Installation Notes

Download the General Instructions for the Installer for your drawings.

These general instructions for the installer are provided to ensure proper selection and installation of Simpson Strong-Tie Company Inc. products and must be followed carefully. These general instructions are in addition to the specific installation instructions and notes provided for each particular product, all of which should be consulted prior to and during installation of Simpson Strong-Tie Company Inc. products.

  1. All specified fasteners must be installed according to the instructions in this catalog. Incorrect fastener quantity, size, placement, type, material, or finish may cause the connection to fail. Prior to using a particular fastener, please consult Connector Fastener Types.
    • Larger diameter fasteners may be substituted for smaller diameter fasteners in connectors provided the larger fastener does not cause splitting in the wood member and the connector holes are not enlarged.
    • Simpson Strong-Tie® Strong Drive® SD Connector screws are available for use with our connectors. They are designed to replace nails in certain products. See Connectors Approved for Use with the Strong-Drive® SD Structural-Connector Screw for more information. Screws not manufactured by Simpson Strong-Tie are not supported in our products.
  2. Fill all fastener holes as specified in the installation instructions for that product. Refer to the Simpson Strong-Tie Fastener Guide for the requirements of the various shaped fastener holes.
  3. Do not overdrive nails. Overdriven nails reduce shear capacity. See Over-Driven Nails in Connectors and Straps for additional information.
  4. Products shall be installed for the use specified. Use the materials specified in the installation instructions. Substitution of or failure to use specified materials may cause the connection to fail. Do not alter installation procedures from those set forth in this catalog. See Terms and Conditions of Sale.
  5. Do not add fastener holes or otherwise modify Simpson Strong-Tie Company Inc. products. The performance of modified products may be substantially weakened. Simpson Strong-Tie will not warrant or guarantee the performance of such modified products.
  6. The proper use of certain products requires that the product be bent. For those products, installers must not bend the product more than one time (one full cycle).
  7. Bolt holes shall be at least a minimum of 1/32" and no more than a maximum of 1/16" larger than the bolt diameter (per the 2015/ 2018 NDS, Section and AISI S100, Table E3a if applicable).
  8. Install all specified fasteners before loading the connection.
  9. Some hardened fasteners may have premature failure if exposed to moisture. These fasteners are recommended to be used in dry interior applications.
  10. Use proper safety equipment.
  11. Welding galvanized steel may produce harmful fumes; follow proper welding procedures and safety precautions. Welding should be in accordance with A.W.S. (American Welding Society) standards. Unless otherwise noted, Simpson Strong-Tie connectors cannot be welded.
  12. Pneumatic or power-actuated fasteners may deflect and injure the operator or others. Pneumatic nail tools may be used to install connectors, provided the correct quantity and type of nails (length and diameter) are properly installed in the nail holes. Connectors with tool embossments or tools with nail hole-locating mechanisms should be used. CSHP coiled strap works with several manufacturers’ full round-head pneumatic framing tools. Find additional information on the CSHP coiled strap. Follow the manufacturer’s instructions and use the appropriate safety equipment. Contact Simpson Strong-Tie. Power-actuated fasteners should not be used to install connectors, unless noted otherwise. Reference pages 163 and 165 of the Wood Construction Connectors Catalog.
  13. Joist shall bear completely on the connector seat, and the gap between the joist end and the header shall not exceed 1/8" per ICC-ES AC13, ASTM D1761 and ASTM D7147 test standards (unless specifically noted otherwise).
  14. Fasteners are permitted to be installed through metal truss plates when approved by the Truss Designer in accordance with ANSI/TPI 1-2014, Section and 8.9.2. Installation of Simpson Strong-Tie Strong-Drive SDS Heavy-Duty Connector screws through metal connector plates requires the plates to be pre-drilled using a maximum of a 5/32" bit. Do not drive nails through the truss plate on the opposite side of single-ply trusses which could force the plate off the truss.
  15. Nuts shall be installed such that the end of the threaded rod or bolt is at least flush with the top of the nut.
  16. When installing hurricane ties on the inside of the wall, special considerations must be taken to prevent condensation on the inside of the completed structure in cold climates.
  17. Unless otherwise noted, connectors shown in this catalog have been designed to be installed at the time the framing members are installed. Contact Simpson Strong-Tie for retrofit suitability of specific connectors including those manufactured in accordance with the hanger options section.

General Connector Installation

Top-Flange Hangers

Flush Framing Example
Flush Framing

Top flange configuration and thickness of top flange need to be considered for flush frame conditions.

Hanger Over Spread
Hanger Over-Spread

If the hanger is over-spread, it can raise the I-joist above the header and may cause uneven surfaces and squeaky floors. The ITS and IUS with up to 1/4" overspread (both sides combined) will not result in reduced download. It will reduce allowable uplift load.

Hanger Not Plumb
Hanger Not Plumb

A hanger “kicked-out” from the header can cause uneven surfaces and squeaky floors.

Prevent Rotation

Hangers provide some joist rotation resistance; however, additional lateral restraint may be required for deep joists.

No Rotation Resistance
No Rotation Resistance

Lack of web stiffeners combined with short hanger allows unwanted rotation.

Rotation Prevented Example 1
Rotation Prevented by Web Stiffeners or Solid Joist and Hanger Height

Hanger height should be at least 60% of the joist height.

Rotation Prevented Example 2
Rotation Prevented by Web Stiffeners or Solid Joist and Clips or Blocking

If hanger height is less than 60% of the joist height, add clips or blocking near the top.

Rotation Prevented Example 3
Rotation Prevented by Lateral Flange Support

Sides of hanger laterally support the top flange of the I-joist.
No web stiffeners required.

Wood Nailers

Correct Attachment
Correct Attachment
Nailer Too Wide
Nailer Too Wide

The loading may cause cross-grain bending. As a general rule, the maximum allowable overhang is 1/4", depending on nailer thickness.

Nailer Too Narrow
Nailer Too Narrow

Nailer should be full width.

Nailer Too Thin
Nailer Too Thin

Or the wrong hanger for the application.

Toe Nailing

Toe Nailing

Toe nailing causes squeaks and improper hanger installations. Do not toe nail I-joists before installing top-flange or facemount hangers.

Positive Angle Nailing

Correct Nailing
Correct Nailing Approx. 45° Angle
Nail Too Long
Nail Too Long
Nail at Wrong Angle
Nail at Wrong Angle

Other Applications

Sloped Joists

For sloped joists up to 1/4:12, there is no reduction. For slopes greater than 1/4:12, see individual product pages or refer to technical bulletin T-C-SLOPEJST.

Multiple Joists

Multiple joists should be adequately connected together to act as one unit.


Use the correct nails. Wood may split if the nails are too large. Hanger nails into flanges should not exceed 0.148" x 1 1/2". Nails into web stiffeners should not exceed 0.162" diameter.

Eccentrically Loaded I-Joists

Supporting a top-flange hanger may require bottom flange restraining straps, blocking or directly-applied ceiling systems to prevent rotation at the hanger location.

Skewed Joists

Joists may be skewed up to 2 1/2° in a non-skewed hanger without any load reduction. Refer to individual hanger descriptions for information allowing any further skew applications.

Notching Joists

Notching of joists/rafters to accommodate sloped conditions in standard (nonsloped) hangers is not recommended and can lead to premature splitting.

Do Not Notch Joist
Do Not Notch Joist
I-Joist As a Header Installation

When face-mount hangers are attached to I-joist headers, backer blocks must be installed to provide a nailing surface for the hanger nails. The backer blocks should be installed on both sides of the web and attached together with a minimum of (10) 0.148" x 3" nails. The hanger nails should extend through the web. Contact the I-Joist manufacturer for additional design considerations.

Face Mount Hanger
Face-Mount Hanger

When top-flange hangers are attached to I-joist headers, a backer block must be installed to prevent the top flange from rotating under load. The backer blocks should be installed with a minimum of (10) 0.148" x 3" nails clinched. Check with the joist manufacturer for additional design considerations.

Top Flange Hanger
Top-Flange Hanger