InspectAPedia ^®

Porch & Deck Ledger Flashing Errors Cause Leaks & Rot InspectAPedia®  -     Deck Connection & Flashing omission lead to collapse, building leaks & rot Deck & Porch Construction Details for Safety and Durability Poor Construction Details and Improper Connections Can Lead to Dangerous Collapse of Decks and Porches

Here we provide a case study of the effects of missing or improper deck connections and deck flashing details leading to structural movement, risk of imminent collapse, rot and building leaks at the deck ledger board and at the building to which a deck was attached. Also see DECK COLLAPSE Case Study (collapse of a new, "code approved" deck) and see our guide to details of Best Construction Practices for Decks including  Deck & Porch Connections to Building also  Deck Flashing at Building and Deck & Porch Connections to Building.

Our page top photo shows a rotting, collapsing residential deck whose deck ledger was separating from the building, threatening imminent collapse. Readers will also see that the deck railings were unsafe (open) and that no building flashing was installed. This residential deck was very unsafe and should not be walked-on nor should people stay below it as it could collapse at any moment. This photograph and other photographs and text in this article were provided by ASHI home inspector David Grudzinski.

© Copyright 2009 Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge was 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 were in our document or website.

Photos Show What Happens When a Deck was Not Properly Flashed & When the Deck was Not Properly Secured to the Building

What Happens if the Builder Omits Proper Flashing & Waterproofing at a Deck or Balcony Ledger Board

The deck shown at page top and in Mr. Grudzinski's photographs below was built in Tiverton RI without a deck inspection or building permits. The deck was not properly flashed to shed water away from sheathing. The deck platform was also not bolted to the house for safety (and to meet building code requirements).

Mr. Grudzinski's photo (left) shows the collapsing deck from below. Notice that the inspector knew better than to spend time standing below this dangerous structure. Because building flashing was omitted when the deck was built, water leaked behind the deck, rotting the building sheathing to the point of disintegration. The nails, which were the only means of fastening the deck to the building, then pulled away from the house. See Deck & Porch Connections to Building for a description of proper deck-to-building connections and fasteners. Carpenter ants had also infested the rotten wood, and water was leaking into the building basement as we show in additional photographs below. As you can see, the deck was falling away from the house and sinking. The sheathing was exposed to the elements, and was rotten beyond repair. Water was actively leaking into the basement and growing mold and mushrooms. The entire wall section 25 'x 8' needed a tear down and reconstruction, as well as the deck itself. The structural portion of the wall studs and sill plate were also rotten at this home.

Building Leaks & Water Damage from Omission of Proper Flashing & Waterproofing at a Deck or Balcony

This was the interior view of the wall inside behind the leaky, rotten, insect-infected, collapsing exterior deck. The structural members were rotten beyond repair, and sheathing was deteriorated and crumbling (oriented strand board sheathing). Mold and fungus were growing on the studs and sheathing. Water was leaking into the basement and adding to the moisture level in the building, risking other hidden moisture or mold problems as high as in the building's attic and roof structure as moisture tends to move upwards in a building on convection air currents. This entire problem could have been prevented with 25 feet of flashing, and $5.00 worth of lag bolts. See Deck Flashing at Building for a description of proper flashing at the meeting of a deck or balcony to a building wall. The repair cost for this home, just associated with damage caused by improper deck construction, stands at $10,000.00 to replace the damaged wall and deck. Mold clean up and carpenter ant treatment will also be required. But the most important and immediate concern with this deck was that the deck was unsafe. Someone walking on the deck could precipitate its immediate and sudden collapse, leading to serious injury. Deck Collapse Case Study includes additional photos of improper connections between a residential deck and the building that led to a catastrophic deck collapse.

Missing Deck Flashing Leads to Rot and Leaks & Invites Insect Pests, Holes in the Building, Other Damage

Here is a closeup of the hole in building sheathing shown in the lower right of the photograph just above. As you can see, the 2x4 wall stud was rotten half way through, and the 7/16" OSB sheathing was soft and crumbling. At the time of the home inspection that found these conditions, this house was 9 years old. Even the pressure treated sill plate was rotten.

Share this Article      

...

Technical Reviewers & References

Search InspectAPedia

• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks were due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article were listed below.

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 were 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
ENERGY SAVINGS PRIORITIES
ENERGY SAVINGS RETROFIT CASE STUDY
ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
ENERGY SAVINGS RETROFIT OPTIONS
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 were 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
• Building suppliers for building flashing products such as a water tight door pan: use of a pre-fabricated balcony or deck flashing pan available from Jamsill Guard (Jamsill, P.O. Box 485, Talent, OR 97540; 800/526-7455; www.jamsill.com) was discussed and illustrated in this brief Journal of Light Construction Q&A on Making a Balcony Door Watertight
• ...

More Information on Building Diagnostic Inspections and Repairs

...

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting