Have you ever tried to pull an I-joist dead-flush with the rim board, only to find the rim sitting slightly proud? It’s not a manufacturing defect—it’s designed that way for a critical structural reason.

In this video, we break down the full anatomy of a high-performance crawl space floor system. From continuous PWT-treated LVL mud sills and Simpson Titan HD screw anchors to engineered load paths, squash blocks, web stiffeners, and why "deeper is cheaper" when optimizing floor stiffness.

TIMESTAMPS

0:00 - Why Rim Board Is 1/16" Taller Than I-Joists
0:29 - Mud Sill Setup & PWT Treated LVL
2:16 - Ditching J-Bolts for Titan HD Screw Anchors
0:00 - Seismic Bearing Plates & Code Requirements
4:54 - I-Joist Layout & LVL Beams
6:16 - Floor Diaphragm & Fastening Schedules
6:51 - Load Paths: Squash Blocks & Web Stiffeners
8:41 - "Deeper Is Cheaper": Getting a Stiffer Floor
9:28 - The Truth About I-Joists and Fire Safety

KEY TOPICS COVERED

• Gravity Load Separation: Why rim board is sized 1/16" deeper than I-joists
• PWT Treated LVL Sills: Utilizing 60' lengths to eliminate splices and unnecessary anchor bolts
• Post-Installed Anchors: Simpson Strong-Tie Titan HD screw anchors vs. traditional cast-in-place J-bolts
• Load Path Engineering: Proper placement of squash blocks, web stiffeners, and 3x3 bearing plates
• System Fastening Schedules: How floor diaphragms transfer loads down to the foundation
• Floor Performance: How to achieve a stiffer floor without extra labor ("Deeper is Cheaper")
• Fire Safety: UL assemblies and APA guidelines for engineered floor systems

RESOURCES & LINKS

APA – Engineered Wood Association Fire-Rated Assemblies: APA Fire-Rated Assemblies

Simpson Strong-Tie Titan HD Anchor Specs: Simpson Strong-Tie

Pacific Woodtech PWT Treated LVL Information: Pacific Woodtech

JOIN THE DISCUSSION: Have you ever caught yourself trying to flush frame an I-joist, or had an inspector question squash block heights? Let us know down below—are you framing 16" O.C. or using the "deeper is cheaper" approach at 24" O.C.?

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