In the fast-paced world of construction, even the smallest of errors can set back your timeline and budget. The most common mistakes often revolve around improperly cut holes in joists—errors that can lead to structural problems and costly delays.
Here are some resources to help eliminate those pain points.
Your On-site Companion
Having our bilingual allowable holes poster readily accessible on the jobsite ensures that everyone working on the jobsite from plumbers and electricians to HVAC experts are on the same page, minimizing the risk of costly mistakes.
The printable poster serves as your quick-reference guide for allowable holes in TJI® Joists, TimberStrand®, Parallam®, and Microllam® headers and beams.
This guide now features a newly updated 24-inch wide rectangular hole for TJI Joists, simplifying the process of running HVAC equipment through joists.
Expert Insights
For a deeper dive, check out our video where Trus Joist Weyerhaeuser territory manager, Steve Rudowsky goes in depth on proper hole placement.
In this video Steve covers:
- Types of acceptable holes: square, round, grouped, rectangle
- Common mistakes when drilling holes in TJI joists
- Proper cutting techniques
- Allowable hole locations, and how to identify no hole zones
- Knockouts: small prepunched hole for convenient running of wires and plumbing supply lines
- Resources for calculations
Precision with ForteWEB® Software
When your project requires more than a one-size-fits-all approach, ForteWEB® Software is your next step. This free, web-based software allows you to enter span and support conditions along with loading information and hole details to analyze conditions that go beyond what our literature covers. ForteWEB details specific conditions of your project, making it a must-have tool for those seeking unparalleled precision.
Additional Resources
The following webpages and documents provide all the information you need to correctly size, locate, and cut holes in TJI joists. If you’re still unsure after reviewing this information, reach out to your regional Trus Joist representative with questions.
- Video: Using Knockout Holes found on TJIs
This video covers "knockouts" which are great for trades looking to speed up productivity by taking the “guess work” out of hole placement.
- TJI Joist Specifier's Guide – USA – TJ-4000
- TJI Joist Specifier's Guide - Canada - TJ-4500
Featuring Trus Joist TJI Joists for Floor and Roof Applications
- Allowable Holes For Trus Joist Products – TJ-9015
A large document with drawings and guidelines for sizing and locating holes. Tip: print this out and post it on your job site for your crew and subs to refer to.
- ForteWEB® software
Perform member calculations and identifies solutions for the conditions and geometry you specify. Size members for a specific spacing, depth or the best economical fit.
- Weyerhaeuser Document Library
Find useful guides on choosing and installing all Weyerhaeuser products
- Specification Center
Need more than what is here? Select your region and look up who your Trus Joist territory manager is to get in contact with them.
Making Repairs
- Holes Too Close to End Bearing – TB-817
Repair detail and maximum span table for TJI joists with holes too close to bearing.
- Weyerhaeuser Header-Off Span Table – TB-319
For certain situations, a typical repair detail may not be sufficient or there may not be enough room to install the required repair materials. Here are some alternate solutions.
- TJI Joists Header-Off Span Table - Canada - TB-860
Details for repair technique of a damaged TJI® joist typically referred to as Header-Off or Headered-Off.
Get the most up to date news on Weyerhaeuser products as well as technical articles written by our own professional engineers here at Weyerhaeuser to help you design, spec and build for quality, performance and savings.
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