Truss Repair Checklist for Solving Jobsite Problems

In this article, you will find some helpful information regarding truss repairs. When there is a field issue, timeliness is critical. The last thing any contractor wants is guys standing around on the jobsite. Truss repairs are required from time to time due to plan issues, design errors, breakage upon delivery or jobsite handling and things “just not fitting” on the jobsite.

I know when I was still designing I made my fair share! I learned from every one of them and it made me a much better designer in the end. It especially helped when I was asked to go out to the jobsite and coordinate. Very embarrassing, but extremely rewarding experience those were!

Here is a fairly comprehensive guideline you can use when that phone call comes in. Feel free to use this if you wish!

General Must-Know Information

  1. Quantity of trusses affected
  2. Truss reference number/label
  3. Are nail-on plates available?
  4. Are there any special load considerations?
  5. Is loading correct?
  6. Can live load be reduced?
  7. Is bracing attached?
  8. Is sheathing attached?
  9. Are there any obstacles? (walls, plumbing, electrical)

Broken Members

  1. Location of break
  2. Are the plates intact?
  3. Has any repair been performed by builder?

broken-web

Stubs

  1. Which end of truss?
  2. Stub length?

Bearings

  1. Specify bearing affected and why (moved, type, size change)

Multi-ply Girders

  1. Jack scab or in-line repair preferred?
  2. Are all faces accessible?
  3. Can additional bearing be used?

SY42 Floors

  1. Both faces accessible?
  2. Any obstructions?
  3. Can chase be closed?

damaged-bottom-chord

Repair Solutions

Scabs

What determines length and nailing of a scab?

  1. Nailing : pounds of force in web of chord, divided by nail holding power equals the number of nails required (on each side)
  2. Spacing of nails : diameter of nails multiplied by the number of nails needed equals nail spacing (round up if decimal)
  3. Length of scab : spacing of nails multiplied by number of nails required equals length of scab

Nail-On Plates

What determines nail-on plate size?

  1. Plate size determined by number of nails required

Plywood Gusset

Rule of thumb: depth is half the width

missing-plate

Jack Scab

When is a jack scab needed?

  1. Damage is too close to joint for required nailing
  2. Forces too great to use nail on plate or gusset
  3. Several trusses in a line need the same repair
  4. Damage or alterations are too extensive to effectively repair trusses

Contractors: How to get the fastest turnaround on a repair? Give as much information as possible!!!!!!!!!!!

I hope you have found this useful. Please feel free to comment below with your thoughts…and if you are brave enough, your repairs!

Christopher Gould – President

Gould Design, Inc.