TJI® Joists

TJI® joists are available in six series. Available depths range from 9½ to 24 inches in standard increments. Standard-size joists (9½"–16") are the most widely stocked through Weyerhaeuser's network of distributors and dealers; deeper sizes (18"–24") are suited for heavier-duty loads in multi-family and light commercial structures. Not all products may be available in all regions.

↑ For exact design properties, moment resistance, and shear values by depth, see the Design Properties tables in TJ-4000. Contact your Weyerhaeuser representative for regional availability.

Frequently Asked Quetions

What are Weyerhaeuser Trus Joist® TJI® joists?
Trus Joist® TJI® joists are engineered wood I-joists manufactured by Weyerhaeuser, designed for floor and roof framing in residential and light commercial construction. They are engineered for strength and consistency, resist bowing, twisting, and shrinking, and are available in long lengths, up to 60 feet, to support more versatile framing plans. TJI joists are manufactured in six series (110, 210, 230, 360, 560, and 560D) and range in depth from 9½ to 24 inches depending on series. Full product and design information is published in Weyerhaeuser's Trus Joist® TJI® joist Specifier's Guide, TJ-4000(US) and TJ-4500(Canada).

What series and depths are available for TJI® joists?
Trus Joist® TJI® joists are available in six series: 110, 210, 230, 360, 560, and 560D. Depending on series, available depths include 9½", 11⅞", 14", 16", 18", 20", 22", and 24". Standard-size joists (9½"–16") are typically the most widely available through local distributors and dealers. Deeper joists (18"–24") are suited for multi-family and light commercial applications. Not all products are available in all regions, contact your Weyerhaeuser representative for local availability or visit Weyerhaeuser’s ‘Where to Buy’ on our website.

Can I cut holes in TJI® joists to facilitate mechanicals?
Yes! Trus Joist® TJI® joists are designed to accommodate field-cut holes in the web for mechanical, electrical, and plumbing. Round, square and rectangular holes are permitted, subject to size and location limits published in TJ-9015 (Allowable Holes for Trus Joist® Products), TJ-4000 (US) and TJ-4500 (Canada). Holes must fall within the allowable zone relative to supports. Field-cut holes are not permitted in the hatched zone near bearings, though pre-engineered knockouts are permitted. Flanges should not be cut or notched. For TJI 360 and 560 joists, a 24-inch wide rectangular hole is also permitted at the center of a simple span under specific conditions. Use ForteWEB® or Javelin® for conditions outside the standard tables.

What is TJ-Pro™ Rating and how does it apply to TJI® joists?
TJ-Pro™ Rating is a proprietary floor performance diagnostic tool developed by Weyerhaeuser, that goes beyond the code’s strength and static deflection requirements to help specifiers, homeowners, and builders gauge a floor’s performance. Based on research conducted on approximately 1,000 floor system assemblies, it assigns a point value up to 65 that corresponds to customer satisfaction. At 45 points, 84% of customers are satisfied; at 65 points, satisfaction approaches 100%. Key factors include joist depth and span, composite action between the joists and floor sheathing, joist spacing, deck thickness/stiffness, and ceiling attachment. TJ-Pro Rating analysis is available through Weyerhaeuser's ForteWEB® and Javelin® software platforms.

Can TJI® joists be used for roof framing?
Yes! TJ-4000(US) and TJ-4500(Canada), include roof span and load tables for Trus Joist® TJI® joists. Note, TJI® joists require a ridge beam or other vertical support at the high end in roof applications. Weyerhaeuser also publishes a Roof System Design Guide (TJ-9005) for additional roof framing details for other Trus Joist engineered wood products. Installation guidance for both floor and roof framing is covered in TJ-9001.

What code evaluations cover Weyerhaeuser TJI® joists?
Trus Joist® TJI® joists obtain code approval through ICC-ES Evaluation Report ESR-1153, recognized under the International Building Code (IBC) and International Residential Code (IRC) for alternative materials. For Canadian projects, refer to CCMC ER No. 13132-R, for applicable Canadian code evaluations.

How should TJI® joists be protected for fire-safe construction?
All floor framing materials, including TJI® joists, benefit from appropriate fire protection. Weyerhaeuser notes in TJ-4000 that applying a protective membrane such as gypsum ceiling board provides passive fire protection for framing systems. For projects requiring specific fire-resistance ratings, TJ-1500 (Fire-Rated Assemblies and Sprinkler Systems) provides detailed fire-rated assembly configurations for Trus Joist® products. Designers should consult TJ-1500 and the applicable building code for their project's fire protection requirements.

Do TJI® joists require bridging or mid-span blocking?
TJI® joist floor framing does not require bridging or mid-span blocking. However, joists must be laterally supported at cantilever and end bearings by blocking panels, hangers, or direct attachment to a rim board or rim joist. Safety bracing must be installed during construction , joists are unstable until laterally braced. Only engineered lumber should be used for rim board and blocking; sawn lumber may shrink after installation. See TJ-9001 for complete installation requirements.

What software is available for designing with TJI® joists?
Weyerhaeuser offers ForteWEB®, a free web-based structural design tool, and Javelin®, a software platform. Both provide TJ-Pro™ Rating and handle design conditions beyond the printed span tables in TJ-4000, including multi-span conditions, point loads, and hole conditions requiring analysis.

What is the difference between TJI 360 and TJI 560 joists?
Both the TJI® 360 and TJI® 560 are higher-capacity series. The TJI 560 has a wider flange (3½" versus 2 5/16") and a thicker web (7/16" versus 3/8"), resulting in higher moment resistance and shear capacity. The TJI 560D is a deep-depth variant of the 560, with a 1.5”x3.5” flange to meet the code recognized 1-hour, 1-layer fire assembly, available in 18"–24" depths. For specific design considerations by depth and series, see the Design Properties tables in TJ-4000, or use ForteWEB® or Javelin® to compare performance for a specific span and load condition.