Improperly built elevated decks can be a huge safety issue. Every year you hear about decks or balcony’s collapsing. Sometimes it results in serious injury and sometimes it can result in death.
When I’m inspecting a deck there are several things I’m looking for, here are a few:
- How is it attached to the home: The ledger board of the elevated deck needs to be attached directly to the band joist, not the siding, with lag bolts and washers. The spacing of the lag bolts will depend on the length and span of the joists. 30 inches for 6-foot joists, 23 inches for 8-foot joists and so on. There should also be 2 lag bolts on either end of the ledger.
- The size and span of the joists will also be a concern: for a span of 24 inches a 2x6 joist should not be longer than just over 8 feet in length, for a 2x8 joist not more than just over 11 feet, and so on.
- Has the ledger been installed over siding material: Because the ledger board will be carrying very heavy loads you must establish a strong and stable connection to the houses rim. In order to do this the siding should be removed. Never install a ledger board over the top of siding, this can weaken the connection.
- Has the ledger board been properly flashed: The ledger board of the elevated deck must be properly flashed. Water can get into anyplace that is not appropriately sealed.
- Have the joist hangers been properly installed. A lot of times I see common deck screws securing the joist hangers and/or other aspects of this deck. Deck screws are not appropriate here as they do not have the shear strength to support the deck. The appropriate nails must be used for these connections.
- The overall structure. Have the proper posts been used, is the framing properly supported by these posts, do the posts have proper footings.
- Guards and handrails are another important aspect. Are the guards high enough (36 to 42) inches? Are they strong enough; most often they are not.
The items above are the most common elements to look for and as you can see some of the building requirements can get a little complicated. This is why it is so important that when you get a deck built that it be done by a licensed carpenter and not your local handyman. And of course when you are buying a home it is important that your inspector notify you of any Inadequacies in construction.
Please be aware that the above information are guidelines only, specific building requirements may vary region to region and municipality to municipality. If you have a concern about your deck you should check with your local building code official.