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Bar Joist Size Database
Browse SJI K-series and LH longspan designations for depth, approximate weight, and standard seat depth — handy when coordinating joist seats with girders and deck.
Bar Joist Browser
SJI Standard Designations & Properties
SJI Joist Designations and Seats
Open-web steel joists are ordered by SJI designation — for example 16K4 means 16″ deep, K-series, chord section 4. Higher chord numbers carry more load at a given depth. LH (longspan) joists cover longer bays with deeper seats. This browser helps detailers confirm depth, approximate weight, and the seat depth that must clear on the supporting girder or masonry pocket.
How to use this browser
- Search by designation (16K4, 24LH…) or filter K-series vs LH-series.
- Review depth, approximate weight per foot, and standard seat depth on the result card.
- Coordinate seat depth with bearing length, fireproofing, and deck profile before releasing joist reactions to the fabricator.
Seat depths that catch shops off guard
Standard K-series seats are typically 2.5″ deep; LH seats are usually 5.0″ (some heavy LH chords use 7.5″). Calling a K seat into an LH pocket — or forgetting the seat when setting girder elevation — creates field shims and RFI delays. Always confirm special seats, extensions, and bridging with the joist manufacturer’s approval drawings.
FAQ
Is weight exact for shipping?
Listed weights are approximate estimating values. Final weights come from the joist manufacturer’s bill of materials.
Does a higher chord number always mean a deeper joist?
No. Depth is the leading number. Chord number changes capacity within that depth family.
Can I select joists from weight alone?
No. Span, load, bridging, and vibration criteria govern. Use SJI load tables or manufacturer software for selection; use this page for designation/seat coordination.
What about joist girders (G series)?
Joist girders are a separate product line with different designation rules. This database focuses on K and LH bar joists.
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