How do I attach a deck ledger board to a brick house in Moncton?

Attaching a deck ledger to a brick house in Moncton requires fastening through the brick veneer into the structural rim joist or band board behind it, with proper flashing to prevent water intrusion. Brick veneer on its own does not have the structural capacity to support a deck ledger, so the connection must transfer loads into the wood framing of the house.

The first step is to determine what is behind the brick. Most homes in Moncton built from the 1970s onward have brick veneer over a wood-framed wall with a 1-inch air gap between the brick and the sheathing. You need to verify this before proceeding. If the home has solid masonry walls, which is less common but possible in some older Moncton neighbourhoods, the attachment method is different and typically involves through-bolts with bearing plates.

For the typical brick veneer situation, you will cut out a section of brick where the ledger will sit. Use a masonry saw to make clean horizontal and vertical cuts, then carefully remove the brick in that area. This exposes the sheathing and allows you to locate the rim joist behind it. The ledger board, usually a pressure-treated 2x10 or 2x12 matching your joist depth, is then lag-bolted or through-bolted into the rim joist. Use 1/2-inch diameter hot-dipped galvanized or stainless steel lag bolts, spaced no more than 16 inches on centre in a staggered pattern. Each bolt should penetrate at least 3 inches into the rim joist.

Flashing Is Critical

The most important detail in this entire process is the flashing. Water getting behind the ledger and into the wall cavity is the number one cause of structural failure in deck-to-house connections, and in Moncton's climate with heavy rain, snow, and freeze-thaw cycles, this risk is especially high. Install self-adhering waterproof membrane, such as Grace Vycor or a similar product, on the sheathing behind the ledger before you bolt it in place. This membrane should extend at least 4 inches above the top of the ledger and wrap down below it. Above the ledger, install metal Z-flashing that tucks up under the building wrap or house siding above and kicks out over the top of the ledger board. This directs any water that runs down the wall face out and away from the connection point.

Between the ledger and the concrete or brick surface, use stainless steel washers or spacers to create a small gap that allows water to drain through rather than pooling behind the board. Standing water behind a ledger is what causes the rim joist to rot over time, and once that happens you are facing a structural repair in the $2,000 to $5,000 range.

After the ledger is bolted and flashed, seal the edges where the brick meets the ledger area with a flexible, paintable exterior caulk. Do not use rigid mortar here because the wood and brick will expand and contract at different rates through Moncton's temperature swings, which range from minus 25 Celsius in January to plus 30 in July.

Finally, make sure your ledger attachment meets the requirements of the New Brunswick Building Code. A building permit is required in the City of Moncton for any attached deck more than 24 inches above grade, and the inspector will pay close attention to the ledger connection because it is the most structurally critical point of the entire deck.

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