It is not uncommon for any residence (single or multi-family) to take advantage of its adjacent outdoor spaces by means of a porch or deck. They're a great way for building occupants to extend the living quarters outside for use in lounging, entertaining, cooking, dining, etc - the list goes on. As Spring approaches and construction or reconstruction of these outdoor structures begins to rise, there is a far-too-common practice among the deck/porch-building industry that is improperly executed and could lead to failure of a deck and possibly worse... personal injury or death. My main objective in approaching any design problem is life-safety - even in a project as seemingly rudimentary as deck design. There is no project too small for careful thought and proper design to preserve the health, safety, and welfare of the general public, and I hold this true with deck ledger design. The mis-usage I'm describing is the attachment of ledger boards to brick or masonry veneer on homes built circa the mid-1950s and beyond, primarily in suburban areas and subdivisions.
Generations ago, buildings were built with real masonry bearing walls on the exterior, for fire-resistance, longevity, strength, and low-maintenance. However, advancements in knowledge of seismic and wind activity have led to less un-reinforced brick being used for structural walls, and the onset of the use of brick or masonry veneers as an outer skin to the home, with a wood or metal-stud backup providing the real structural strength within. Again, this technique is especially prevalent in today's new residential construction. With the older buildings found mainly in more densely-populated, older urban neighborhoods, their multi-layer masonry walls could be used for attaching those deck ledgers directly, with the proper method of anchorage, of course. However, the single-layer veneers are highly inadequate for supporting a deck ledger, as they are non-structural and used only as a barrier of weather protection from the underlying structure, in lieu of siding for example. A deck ledger board is a long board set against the house and used to attach the main joists of the deck with hangers; therefore, they form a major structural component of the deck as a whole.
If you're in a home or apartment building where the walls are truly masonry or if you simply have siding over the stud wall, then this article isn't meant for your project, as those substrates are adequate for direct-ledger-attachment. However, if you are building a deck onto a home with masonry veneer as an aesthetic "skin", than I consider this to be required reading. Those veneers are not designed nor are they built for ledger attachment. Meaning that bolting the ledger board solely to this veneer and letting that be the main support against the wall is a no-no. The ledger could pull away from the wall and take a large chunk of the masonry with it, because they are not properly tied back to resist such force. Also, one layer of brick veneer is not adequate to support the weight of a fully furnished and occupied deck - the brick can compress and be crushed by those loads causing catastrophic failure. You also cannot simply set a bolt through the veneer and tie it back to the main structure beyond because this stand-out of the bolt through a non-structural material is too great and could cause the bolts to bend and break, or fail in one of the other aforementioned ways.
The best methods for supporting a deck in this condition are to either find a spot of easily exposed concrete foundation or wood structure to which a ledger can be set directly against and thoroughly bolted, or (the main focus of this article) to build the deck "free-standing" with only minor anchorage to the brick veneer to keep it from drifting. In lieu of a ledger board attached to the house to carry a significant portion of the deck load, you would have a beam similar to that at the outer edge of the deck, but situated a few feet away from the exterior wall so that the edge against the house is actually cantilevered. Then that edge can be anchored to the veneer to resist minor shifting, but nothing more. This is the method recommended by the American Wood Council (AWC) and should be put into practice by all design professionals (architects, engineers, etc) and deck builders, carpenters and contractors, as well as enforced strictly by the governing bodies within every municipality.
For further information on proper deck construction: http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf
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