Q&A: Bolting a Ledger to Brick Veneer

A.Christopher DeBlois, P.E., an engineer with Palmer Engineering in Chamblee, Ga., responds: Whenever there is a design alternative, I generally recommend against bolting a deck ledger board to brick veneer. I prefer to provide independent support adjacent to the house, usually with posts and beams. In many cases that is impractical or undesirable, however, so the deck gets bolted to the house.

The brick veneer on a house typically supports its own weight and nothing else. The section of the CABO One & Two Family Dwelling Code on lintels states that “masonry veneer shall not support any vertical loads other than the dead load of the veneer above.” When independent support is provided against the house to support the deck, standard practice is to bolt through the brick and the band at the house to provide lateral stability for the deck. That way the brick veneer is not forced to carry the weight of the deck, so there is no violation of the lintels section of the CABO code.

Although I’m against bolting the deck ledger to or through the brick veneer, I recognize that it’s not an uncommon detail and that building officials often approve it. With that in mind, here are some thoughts if you choose such an approach:

I have heard the direct bolting of a deck ledger to the house through the brick justified by arguing that because the bolts extend to the house band, the band will carry the deck weight. I disagree. With a separation of several inches between the back of the deck band and the face of the house framing, the bolts will bend or rotate before the weight is carried by the house framing. As soon as that starts to happen, the bolts will bear on the brick, and the veneer will be carrying the load. The good news is that in most cases the brick has substantial extra capacity. In fact, the capacity of the bolt-to-brick component of this connection will generally exceed the capacity of the bolt to the deck ledger itself. As a result, the required size and spacing of bolts are no different than for typical wood-to-wood connections (see Practical Engineering, 3/96). I strongly recommend bolting all the way through the house band to properly transfer forces pulling the deck away from the house into the framing instead of into the brick. Also, no lag bolts are allowed. And pay careful attention to sealing bolt holes and flashing against the house.

In some situations, requiring brick veneer to support the weight of a deck is a bad idea regardless of what local building officials allow. Do not bolt the deck band to the brick veneer if you suspect that there are no brick ties (all too common on older houses), if the condition of the brick and mortar is questionable, or if the brick ledge or footing supporting the brick veneer is not sound and stable.

Finally, a number of circumstances may warrant contacting a structural engineer for guidance. If there are large openings in the brick (for a bank of full-height windows, for example), stresses in the brick at the sides of these openings may be too high to permit support of deck loads. Similarly, if you need to support the end of a beam instead of just a continuous, uniformly loaded band, special support will be necessary.