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Porch & Deck Ledger Connections to Buildings - Construction Details InspectAPedia®  -     Deck & Porch Construction Materials Choices Deck & Porch Construction & Structural Fasteners Deck & Porch Construction Details for Safety Deck & Porch Railings, Code Requirements, Safety Finishes for Exterior Decks Poor Construction Details and Improper Connections Can Lead to Dangerous Collapse of Decks and Porches

Here we discuss critical safe-construction details for decks and porches, including avoiding deck or porch collapse and unsafe deck stairs and railings. This article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons. Also see our review of that book. Also see DECK COLLAPSE Case Study (collapse of a new code-approved deck) and DECK FLASHING LEAKS, ROT Case Study for an example of an older deck with rot and collapse due to improper construction and missing building flashing.

© Copyright 2009 Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Photos & Construction Details of Unsafe Compared with Safe Deck & Porch Connections to the Building

Deck Ledger Board Connection to Building Band Joist

Though deck failures are rare, ledger connections are typically at fault when they occur. Through-bolts make the strongest connection, but adequately sized lag screws can also work. With either, it is critical to flash the ledger area and to only use metal components that are compatible with pressure-treated wood. Our photo (left) shows what can happen if the deck ledger board is simply nailed to the structure. Deck Collapse Case Study includes additional photos of improper connections between a residential deck and the building that led to a catastrophic deck collapse.

Band Joist-to-House Connection.

Ledger-to-Band Joist Connection & Bolt Spacing Requirements

The table immediately below gives the bolt spacing requirements for connecting a deck ledger to the building when the ledger board is bolted directly to the structure.

Table of Bolt Spacing for Deck Ledger Spaced Away from the Building

Spacing for bolts and lags used to connect the deck ledger to the building are shown in the table at above-right (ledger bolted directly to the building), and at in the figure at left for deck ledgers that are spaced away from the building. Through-bolts are the most reliable connection, but lag bolts are adequate (photo, above left) as long as they are long enough to fully penetrate the band joist. For through-bolts, drill holes 1/16 inch larger than the bolt. For lags, drill a full-diameter hole for the unthreaded portion and a smaller hole (65 to 75% of the lag’s diameter) for the threaded portion. Use washers under the head of the lag bolt or at both ends of through-bolts to keep the head from crushing the wood. Soak the holes with a preservative before inserting the bolts.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Also see DECK COLLAPSE Case Study (collapse of a new code-approved deck) and DECK FLASHING LEAKS, ROT Case Study for an example of an older deck with rot and collapse due to improper construction and missing building flashing.

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• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
  Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
  
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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

EXTERIORS of BUILDINGS
STRUCTURAL INSPECTIONS & DEFECTS
ADVANCED INSPECTION METHODS
AGE of a BUILDING - how to determine
BEST CONSTRUCTION PRACTICES GUIDE
CHIMNEY INSPECTION DIAGNOSIS REPAIR
Cracks, Checking or Splitting Beams & Log Homes
CRAWL SPACES
DECK & PORCH CONSTRUCTION
  Deck Piers & Posts
  Deck & Porch Connections to Building
  Deck Flashing at Building
  Deck & Porch Structural Fasteners
  Deck & Porch Steps or Stairs
  Deck & Porch Railings
DECK COLLAPSE Case Study
DECK FLASHING LEAKS, ROT Case Study
DEFINITIONS of Mobile Home, Doublewide, Modular, Panelized
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DISASTER BUILDING INSPECTION & REPAIR SAFEY
EARTHQUAKE DAMAGED FOUNDATIONS
ENERGY SAVINGS in BUILDINGS
FLOODS IN BUILDINGS-priorities
FOUNDATION BULGE or LEAN MEASUREMENTS
FOUNDATION CRACKS & DAMAGE GUIDE
FOUNDATION WATERPROOFING
FRAMING DAMAGE, INSPECTION, REPAIR
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRT PLYWOOD
LOG HOME GUIDE
PANELIZED CONSTRUCTION & KIT HOMES
MODULAR HOME CONSTRUCTION
MOBILE HOMES, DOUBLEWIDES, TRAILERS
MOISTURE CONTROL in BUILDINGS
ROOFING INSPECTION & REPAIR
ROT, FUNGUS, TERMITES
  TERMITE SHIELDS vs TERMITICIDE
ROT, TIMBER FRAME
SINK HOLES

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Wiley.com and also at Amazon.com. See our book review of this publication.
• Manual for the Inspection of Residential Wood Decks and Balconies, by Cheryl Anderson, Frank Woeste (Forest Products Society), & Joseph Loferski, October 2003, ISBN-13: 978-1892529343, $39.00 at Amazon.com or at the InspectAPediaBookstore
• ...

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