A Realtor from a Xenia office recently commented that there had only been one deck in the last two years that we had not thrown the book at. Thinking about that statement I realized he was probably correct.
Unfortunately most of the decks we inspect, even professionally built decks are badly constructed and potentially dangerous.
Ledger boards which attach the deck to the house structure must be secured to the interior framing with bolts which must be in a zig zag pattern. It may not be attached to a brick (veneer) on the outside of the house. The bolts cannot be less than two inches from the top or bottom of the board. There can be no siding between the board and the structure, There must be flashing over the top of the ledger to prevent water getting behind the board and causing wood rot (the main reason for deck failures).
Beams are one of the biggest issues we see all the time. Beams that are undersized for the potential load pose a serious threat to any deck. The longer the span the bigger the beam needs to be. Beams should always be larger than the joists. Beams must be bolted to the posts with at least two bolts. Nails or screws are not considered structural and are not permitted because it is too easy for them to pull out of the wood under load. Boards incorrectly sandwiched together.
Joists must not be undersized for the span (length) and correctly spaced. Joist hangers must match the size of the joist it is supporting. The joist hangers must have a nail in every applicable hole and are more often than not attached with the incorrect fastener which can pose a very serious safety issue.
Posts must be a minimum of 4’x6″ and preferably 6’x6″, smaller 4″x4″ posts are not permitted for deck building. If there is any potential for sway in the deck (the end of the deck is not against a structure) then there must be a form of sway control to prevent lateral load movement. These may be big ‘X’s” bolted between the posts. Posts should be notched to take the weight of the beam.
Stairs have so many potential issues. One being supported by dropped headers that are inadequate is unfortunately very common and very dangerous, due to the potential for a collapse. Step heights not been consistent or the correct height, handrails that installed and are graspable. Landings that are secured with nails rather than bolts.
Flooring on older decks is often rotten and can give away when a chair leg goes through it. Boards should be screwed not nailed, boards should be installed crown up (the grain at the cut end of the board should hump up in the center) to prevent bowing which could cause a trip hazard.
Railings must be installed on any deck that is thirty inches above grade, 4×4 posts may not be notched to secure them. Must be at least thirty six inches high. Picket spacing and spacing between railing and floor are all critical.
NOTE: This is not the complete list of problems we inspect for
While not always required by code in our area, the posts should be notched to take the weight.