National Home Inspector Exam Prep Podcast

08 - DECKS (PART 1)

Charles Bellefontaine Season 8 Episode 8

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Deck failures cause more injuries and deaths than any other home system component. This first of three deck episodes focuses on materials, flashing, and the critical ledger attachment.

We begin with materials:
- Preservative-treated wood (noting the 2003-2004 switch from CCA to more corrosive ACQ/MCQ/CA-C)
- Naturally durable woods (redwood, cedar)
- Composite decking materials
- Proper fastener selection (hot-dipped galvanized or stainless steel—not aluminum or electroplated galvanized with new treated wood)

Deck flashing receives extensive coverage because water damage to ledgers is a primary collapse factor:
- Integration with door threshold flashing and wall drainage planes
- Diverting water away from ledger attachment points
- Allowing unavoidable water to drain (not remain in contact with materials)
- The limitation that sealants are not substitutes for flashing

The deck ledger attachment section is crucial:
- Must resist 3,000 pounds lateral load plus vertical loads
- Minimum ½" diameter lag screws or machine bolts (not carriage bolts)
- Proper washer use and staggered installation patterns
- Maximum 1" gap between band/rim joist and ledger
- No attachment through wall coverings (especially brick veneer)
- Lateral load connectors required (commonly absent)
- Special concerns with I-joists and floor trusses

Typical ledger defects include using nails only, inadequate bolt quantity/size, wrong bolt types, missing washers, non-staggered installation, attachment through wall coverings, and missing lateral load connectors. Understanding proper ledger attachment could literally save lives.

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