A lay-on gable frame is typically connected from the top during truss placement, but after sheathing is installed, this connection is no longer visible for the building inspector to verify. This creates a need for an alternate connection that is visible from below. This guide describes a simple, cost-effective, toe nail connection between the lay-on gable frames and supporting truss system that is visible after sheathing is installed.
Design Guide
Designer/Plan Reviewer Checklist

Step-by-Step

Intro

Design Guide

  • A lay-on gable frame is typically connected from the top during truss placement, but after sheathing is installed, this connection is no longer visible for the building inspector to verify.
  • This creates a need for an alternate connection that is visible from below.
  • The connection described in SRR 1505-02 is a simple, cost-effective, toe nail connection between the lay-on gable frames and supporting truss system that is visible after sheathing is installed.
  • In designing the connection, assumptions were made with the intent for the connection to be applicable to a majority of situations encountered.
  • It is the building designer’s responsibility to ensure that the assumptions listed are equal or conservative to project requirements.
  • The following steps will assist the designer in verifying whether this connection is applicable for the project.

Step 1

Verify Loading

  • ASCE 7-10 is referenced by IBC 2012 and 2015
  • Project specific loading that does not exceed 5 psf dead load in total is acceptable
  • The project must meet the criteria for C&C determination of wind pressures including:
    • The building must not be subject to across wind loading, vortex shedding, galloping, or flutter
    • The site must not be subject to channeling effects or buffeting due to upwind obstructions

Step 2

Verify Project Dimensions

  • The project should be a regular shape - i.e. a building without irregularities in spatial form per ASCE
    • See ASCE 7-10 Table 12.3-1 or 12.3-2 for criteria
  • Mean roof height should be no more than 30’

Step 3

Verify Project Attributes

  • Values more conservative than those listed (e.g. lower wind speed, exposure category) are acceptable

Step 4

Verify Connection Location

  • Trusses and lay-on gable frame members may be spaced a maximum of 24" o.c.
  • The connection location analyzed represents the largest tributary area on a typical layout
  • Alternative locations are acceptable provided that the tributary area does not exceed that shown

Step 5

Verify Materials and Fasteners

  • Framing material must be SPF (Specific Gravity = 0.42) or better
  • Nails must be 10d (0.131 x 3.25”) or better
  • Better materials and fasteners will increase the capacity of the connection and make the connection more conservative.

  • Ensure fasteners meet spacing requirements:
    • Supporting truss
      • Edge distance = 4D (4x0.131” = 1/2”)
      • Row spacing = 5D (5x0.131” = 5/8”)
    • Lay-on gable
      • Edge distance = 1.5D (1.5x0.131” = 3/16”)
      • Row spacing = 1.5D (1.5x0.131” = 3/16”) and ½ spacing between rows (0.5x0.655” = 5/16”)

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