Red-I™ I-Joists

Forty years ago, our founders developed the engineered wood I-joist. Engineered to provide strength and consistency, Red-I™ I-joists have become an integral part of floors, ceilings and roofs in commercial applications. The dimensional stability of Red-I™ I-joists helps them resist the warping, twisting, and shrinking that can lead to squeaky floors. Red-I™ I-joists are strong yet lightweight and include a wide range of sizes and depths in lengths up to 80 feet, giving you extraordinary design freedom. Because they're faster and easier to install than traditional framing, you save on labor.

Red-I™ I-joists are manufactured using high-quality, engineered wood — including LVL flanges and RedBuilt’s proprietary OSB web. In addition to the standard parallel flange configuration, some series are available with tapered profiles for added design flexibility. Camber is also available in some series, upon request. Red-I™ I-joists offer architects, engineers, commercial building owners and commercial contractors practical and economical solutions for virtually every structure, while increasing design confidence and building quality.

Features & Benefits

  • Uniform and predictable strength
  • Can carry heavy loads over long spans while using wood economically
  • Manufactured to resist twisting, bowing, and shrinking

Labor Savings

  • Light weight speeds installation
  • Trimmable on the job site — no special tools are required
  • Pre-punched knockouts for wiring
  • LVL flanges are easily nailed, unlike some alternative materials
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available Sizes

Red-I Joists Descriptions

  • Red-I45


    Top and bottom flanges of 1 1/2" x 1 3/4" RedLam LVL with 7/16" OSB web.

  • Red-I65


    Top and bottom flanges of 1 1/2" x 2 1/2" RedLam LVL with 7/16" OSB web.

    • Available in a tapered profile (Red-I65T). Check with your technical representative for availability.
  • Red-I90


    Top and bottom flange of 1 1/2" x 3 1/2" RedLam LVL with 7/16" OSB web.

  • Red-I90H


    Top and bottom flanges of 1 3/4" x 3 1/2" RedLam LVL with 7/16" OSB web.

  • Red-I90HS


    Top and bottom flanges of 2 1/2" x 3 1/2" RedLam LVL with 1/2" OSB web.

    • For heavy loads and 8' on-center roof systems.
    • Provides increased bending strength and stiffness

Red-I Joists Depths

  • Red-I 45

    9 1/2" - 16"

    Red-I 45

  • Red-I 65

    11 7/8" - 30"

    Red-I 65

  • Red-I 90

    11 7/8" - 30"

    Red-I 90

  • Red-I 90H

    11 7/8" - 30"

    Red-I 90H

  • Red-I 90HS

    11 7/8" - 32"

    Red-I 90HS

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RedBuilt™ engineered wood Red-I™ I-joists are suitable for a wide variety of commercial and industrial applications where design efficiency, installed cost, labor savings and aesthetics are primary considerations. Over the last five decades, RedBuilt™ has become the first choice of architects, engineers, contractors and building owners on a diverse array of projects including:

  • Office buildings
  • Schools and universities
  • Strip malls
  • National chain store locations
  • Hotels and motels
  • Multifamily housing
  • Manufacturing facilities
  • Heavy industry sites
  • Large storage facilities


RedBuilt™ offers a variety of solutions for small to large retail buildings as well as strip centers. An open floor plan is often the primary requirement as it allows the owner/developer the flexibility to create a market specific and relevant lease space.

Whether it’s our Open-Web Trusses or Red-I™ I-joists, RedBuilt can provide design assistance and system cost analysis during the concept phase of the project helping the client on the front end so there are no surprises on the back-end.


At the heart of RedBuilt’s resume is how we’ve contributed to thousands of successfully designed office spaces. RedBuilt’s experienced group of Technical Representatives bring a wealth of knowledge to help you work through the most difficult design requirements.

Floor performance or, how a floor feels, is often a major design consideration. With the aid of our technical team and the FloorChoice™ floor rating system RedBuilt can help you design a floor that balances the need for both economy and performance.

In addition to floor performance, our team can provide guidance related to how other trades interface with our products, specifically, plumbing, HVAC and fire & sound.


From long span gymnasium roofs to carefully designed classroom floors, RedBuilt’s Red-I™ Joists, RedLam™ LVL and our lineup of Open-Web Trusses provide ample solutions for this building category.

Our experience with school work goes back to the 1960s. Needless to say, we understand the processes involved and the level of detail required to make these projects a success.

Our Red-H™ open-web truss can span up to 120’ and has been used to cover many school gymnasiums. In contrast, our Red-I65™ joist is used on many shorter span applications where economy is desired.

If you need design assistance on commonly used RedBuilt products, please give your local rep a call. They will help you through the design process.


Apartments, Condos, Assisted Living Facilities, Hotels and Motels all share the same design challenges; certified fire & sound ratings, economics and post-sale logistics. Owner/Developers are looking for companies like RedBuilt™ that can provide an economical floor or roof joist and provide the shop drawing and package/delivery logistics required to keep the project coming in on time.

Likewise, general & framing contractors need to partner with companies like RedBuilt™ that understand their specific logistical needs so they too can perform on time and under budget. RedBuilt™ will help work through all the common “gotchas” on Multi-Family projects like plumbing drops, duct penetrations & sheathing layout. Our experienced team can help you save money.


Efficiency is the name of the game when it comes to designing roofs and mezzanines in the warehouse category.

The primary challenges with this building type are efficiently supporting the vertical loads and reconciling all the seismic forces. Because there are very few interior walls, the seismic forces are resolved at the outside walls.

RedBuilt™ offers efficient designs with its Red-I™ I-joists and double chord Open-Web trusses. Give your local RedBuilt representative a call for design assistance.

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common questions

q1 What sizes of I-Joists are available?

q2 Do Red-I™I- joists meet the requirements set forth in the U.S. Green Building Council’s (USGBC®) Leadership in Energy and Environmental Design (LEED®) standard?

LEED® – NC (new construction) is a commonly used building rating system designed to accelerate the development of green building practice. While products such as Red-I™ I-joists are not LEED® certified on an individual basis, they may contribute to point totals for a “whole building” certification. For example, the following items may be viewed as contributors toward points in the LEED® rating system:

  • RedBuilt™ offers FSC® credits for our Red-I™ I-joist products as well as other products we manufacture or distribute. Consult your local RedBuilt™ technical representative for availability. 
  • The Low Emitting Materials section (EQ 4.4) recognizes composite wood that is free from urea-formaldehyde resins. RedBuilt™ does not use urea-formaldehyde resins in any of its engineered lumber products. Material Safety Data Sheets (MSDS) are available here.
  • RedBuilt™ products may qualify for Regional Materials (MR 5.1 & 5.2) for projects located within a 500 mile radius of Portland, OR.
  • Hardware accessories to Red-I™ I-joists such as Simpson Strong-Tie hangers may qualify for Recycled Content (RC 4.1 & 4.2). For more information visit Simpson’s website at

q3 Are there special considerations when using double Red-I™ I-joists?

Yes. With double Red-I™ I-joists, if a load is applied to the side of one member, you must connect the two Red-I™ joists together at the loading point to transfer the load equally into both members. For more specific information, see detail 7 on page 11 of the Red-I Joist Specifier’s Guide. Typically, sheathing is not nailed to both Red-I™ I-joists, which leaves one joist with an unbraced compression flange. To ensure the lateral stability of both joists when loads are applied from above, the Red-I™ I-joists must be connected as shown in detail 9 on page 12 of the Red-I I-Joist Specifier’s Guide. Often, a rectangular member may be the simplest option.

q4 Is the 11⁄2"-thick flange on commercial Red-I™ I-joists sufficient for the nail penetration required by building code diaphragm tables?

Yes. A 11⁄2"-thick (or thicker) flange meets the fastener penetration requirements stated in building code diaphragm tables such as IBC Table 2306.3.1. For other building codes, calculations per the 2001 ANSI/AF&PA National Design Specification for Wood Construction consider fastener penetration into the main member and show that a 11⁄2" penetration does not reduce the lateral nail capacity.

q5 Does RedBuilt™ provide any rated fire assembly details?

Yes. RedBuilt™ provides a number of fire assembly details, which can be downloaded here.

q6 Where are the allowable holes for the I65, I90 and I90H?

11⁄2" knockouts at approximately 12" on-center available in most joist series. Joists may be oriented with knockouts at top or bottom.

q7 Are tapered and cambered Red-I™ I-joists available?

Yes. RedBuilt™ offers the Red-I65T™ series I-joist in a single slope, tapered profile to provide minimum roof slopes for drainage. For more details, refer to our Tapered Joist Design Guide. A nominal camber can also be built into some Red-I™ I-joist products (see Red-I™ I-Joist Descriptions on page 4 of the Red-I Joist Specifier’s Guide); contact your RedBuilt™ representative for more information.

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