Most failures of decks, balconies and railings can be avoidable if properly designed but when a collapse occurs it usually leads to personal injuries and even death. According to the North American Deck and Railing Association (NADRA), “It’s estimated that 2.5 million new or replacement decks were built last year. Almost every new home being built today includes an elevated deck or porch. And, existing decks on older homes are being replaced at a very high rate. In fact, the number of personal injuries and deaths related to decks each year is likely to continue to rise because more decks are being constructed each year and existing decks are deteriorating.” Let’s examine the design, construction and inspection of these systems.
When adjusters are called to investigate collapsed decks, balconies and/or railings, what do they need to focus on? What should they be looking for? What are the signs of failure and collectible evidence is available or may be required?
Here is a quick checklist of some items to look for:
- rotting or splitting wood framing members
- loose or missing nails, screws or anchors
- missing, damaged or loose support beams
- unstable, shaky handrails or guards
- corroded connections at deck ledgers and hangers
- proper type, use and size of connectors (bolts versus nails)
- perimeter house flashing at the deck or balcony interface
- height and location of railings
The International Residential Code (IRC) recommends specific minimum live and dead load requirements for decks, balconies and porches including snow load if applicable, wind load and other lateral loads such as horizontal impact. The IRC requires these systems to withstand a minimum of 40 psf gravity loading plus the weight of the structure and for a cantilevered structure to withstand 60 psf loading. Likewise, hand railings and guards have specific loading requirements which are based on a lateral load with impact of 50 lbs per linear foot or 200 lbs at any point and in any direction depending on building use and occupancy. There is also information in the IRC for specific framing member type, size, span and spacing requirements and conditions. There are even requirements for drilling and notching of structural floor framing members.
These items are not in any particular order but they are just as significant when investigating a collapsed deck, balcony or railing. Most situations can be preventable and avoid problems later. The more common issues contend with the ledger attachment not in accordance with the plans or the handrail heights are not per code, or the builder hasn’t requested the required inspections prior to occupancy and use of the structure.
Connections – Connection are a critical element in the design and construction of these structures and must be checked regularly. Nail connections can be problematic because, unlike bolts or straight threaded fasteners with washers, nails can pull out.
Flashing – Check to make sure the flashing is of quality and properly installation because a system with no flashing is detrimental to the stability of the structure. Even if there is flashing, it can still fail causing wood framing members to rot and lose their strength.
Railings – Check the soundness for stability, measure the height for code violations and visually inspect the railings for weakness and proper attachment because they require special attention. Railing design must adhere to local building codes that are designed to ensure their safety.
Changes – Keep up with any design changes during construction.
Building inspectors, like deck builders and homeowners, are constantly being challenged to keep up with the deck industry standards, the State and local amendments and the model building codes. The IRC provides prescriptive provisions for updates and/or changes to their minimum regulations every three years. New building materials and deck-related products appear in the market on a regular basis.
Consulting with other inspectors, reading industry magazines, and monitoring state building and code official association Web sites are all good ways to stay abreast of new products and inspection challenges. The results of a thorough plan design review, good construction methods, and continual building inspections generally go unnoticed. Deck inspections which are so critical should focus on and continue to be the emphasis of deck safety and quality of deck construction to minimize, prevent or ultimately eliminate deck, balcony and railing collapses.
Allan Abbata is a senior consulting engineer at Warren and a licensed professional engineer in South Carolina, North Carolina, New York, New Jersey, Pennsylvania, Massachusetts, Missouri, Texas, Alabama, Maryland, Minnesota and Virginia. Allan holds a Bachelor of Science in Civil Engineering. He has more than 40 years of applied engineering expertise to include in-depth knowledge of building codes, rules and regulations that guide design. Allan has also prepared construction drawings and specifications, provided on-site supervision and inspection of construction projects, and. has overseen project management and responsibility for overall performance of building contracts while also serving as the client’s liaison with local, state and federal agencies and municipalities.