You cannot help but wonder if there is a deck contest in most suburban communities. “My deck is bigger and better than your deck.” There are even “How-to” shows on television solely dedicated to the backyard and a family’s deck. The challenge for the home inspector is… there are a vast number of decks constructed by those very homeowners and they were not built well. In order to build a deck construction “foundation’, we should look at the total deck picture from foundation to flashing.
Most of the time an exterior deck is constructed of pressure treated lumber. There are several variations of this lumber and different manufacturers have different treating methods but this lumber is designed for 30 – 40 years of useful life. The top of the deck flooring can be conventional wood or a composite material. Wood flooring can last about 10 years and a composite decking can last 25 -30 years.
A wood deck does not have the capacity to be self supporting. There has to be some form of mechanical support and fastener to marry the various elements together. A galvanized joist hanger will not last forever. The environment and elements which they are subjected to can greatly cause different lifespans and outcomes. In some cases the joist hanger does not last as long as the material it is designed to support. Any other fasteners, through bolts, lag bolts, nails, and screws, should also be exterior rated. This would mean they are either galvanized or stainless steel. You should never see conventional hardened nails or screws on an exposed material like an exterior deck.
Deck construction should be very similar in concept to conventional home construction. A deck has to be built on a solid foundation. This foundation can vary depending on the zone of construction. A deck built in the southeast might not have to have a deep frost footing where a deck constructed in the north would have to have a foundation that extends below the frost line. Some decks have spread bases and others have deep columns. Many times these bases will not be accessible for inspection nor visible without excavation.
There are several challenges with deck foundations. One contractor or homeowner might use a tube form and use entirely concrete as a foundation where another might imbed the column or post directly in the soil or within the concrete. The tube would require a mechanical connection to keep the column from rotating or sliding where the direct column would not. But, the direct column, embedded in the concrete would be subject to deterioration and accelerated failure.
June might be National Deck Inspection Month but every should be deck awareness day. More than 2 million decks are built and replaced each year in North America. InterNACHI estimates that of the 45 million existing decks, only 40 % are completely safe.
A The BrickKicker inspector is trained and an expert in the deck inspection. Regardless of whether you are purchasing a home or an existing home owner do not hesitate to contact you local The BrickKicker for a deck inspection.