Many natural builders use wooden TJI engineered joists for floors and roofs. This online specifier’s guide makes it easy to determine what size TJIs to use.
From Custom Truss LLC:
“What are TJI Wooden Floor Joists?
TJI joists offer an excellent alternative to wooden floor trusses or flat roofs. These high-tech joists combine webs of O.S.B. (Oriented Strand Board) and flanges made from Microllam. They are patterned after steel I-beams. Next time you pass a commercial construction project take a look at the steel beams. Shaped like an ‘I’ they have very narrow centers with heavy flanges on top and bottom. Look how much weight they can support. Wooden TJI joists work the same way.
Why use Wooden TJI Joists?
TJI joists can use as little as one-third of the wood used in traditional sawn lumber. Resource-efficient, engineered wood TJI joists are manufactured to resist the shape-changing effects of temperature and moisture. Long length, lightweight and versatile, TJI Joists use an innovative design to help prevent squeaky floors and can be easily drilled and cut for plumbing and ductwork.”
From Woodbywy.com:
“Advantages:
• Uniform and Predictable
• Lightweight for Fast Installation
• Resource Efficient
• Resists Bowing, Twisting, and Shrinking
• Significantly Reduces Callbacks
• Available in Long Lengths
• Limited Product Warranty
Why Choose Trus Joist® TJI® Joists?
• Engineered for strength and consistency
• Efficient installation saves time and labor
• Longer lengths allow more versatile floor plans
• Less jobsite waste
• Fewer red tags and callbacks”
Text and images source: Custom Truss LLC
Source text and specifier’s guide: Woodbywy.com
This interesting article goes into the history and details of engineered joists. One benefit not mentioned in my blog post above: TJIs can often be spaced further apart, thus cutting costs and labor.
http://bct.eco.umass.edu/publications/by-title/the-evolution-of-engineered-wood-i-joists/