If your building department has adopted the 2009 IRC code you may need to follow a more strict set of rules for installing ledger boards to deal with lateral loads. There is certainly no harm in installing a few of these devices on any deck…well, except for the actual process of installing them. The additional work and costs involved with gaining access to the inside of the floor framing and the floor sheathing above, precludes the practical use of these devices in construction on many existing homes. Homes with finished basements, or second level decks, for example, would require more intrusive work than is expected in deck construction. For this reason, its worth considering if they are necessary for each deck. If access is available, and the deck is more than just a few steps above the ground, you might as well install the devices.
The lateral load devices become a popular topic after it was included in the widely adopted 2009 International Residential Code. The device is intended to address the potential insufficient connection of the band joist of house to the floor joists. By connecting the deck joists to the house joists directly, the band joist is less likely to be pulled from the house by a collapsing deck. With this understanding in mind, other methods for bypassing the band joist can be considered. For low-level decks merely sinking enough support posts in concrete piers can achieve sufficient lateral restraint. When a deck is built into an inside corner of a house it is also provided additional lateral stability that may preclude lateral devices. There are many design options to consider before lateral devices “must” be installed.