Crew is hanging a 12 by 16 deck off a two-story brick house.

Major issues:

1. No flashing — This is the biggest problem. Without flashing above the ledger, water will infiltrate behind the ledger, rot the rim joist/sheathing, and cause structural damage. Install a self-flashing membrane (e.g., Grace Ice & Water Shield or Z-flashing) above the ledger, sealed to the brick with polyurethane caulk.

1. Lag bolts through brick only — 3/8" x 4" lags may not penetrate far enough into the structure behind. You need to anchor into the rim joist or structural framing. Consider through-bolts (1/2" x 8") with washers, or lag shields/expansion anchors rated for brick and verified framing behind.

1. No gasket/seal between ledger and brick — Even with flashing, you should use a compressible gasket or sealant (like Vulkem) between the ledger and brick to prevent water migration.

1. Spacing — 24" o.c. is acceptable for 2x10 joists at 16" span, but verify local code requirements (IRC R502.5.1).

Immediate action: Stop hanging joists. Remove the ledger, install proper flashing, seal the interface, and use adequate anchors into structural framing. If you can’t verify what’s behind the brick, consider surface-mounting the ledger with appropriate masonry anchors rated for the load.

This work likely violates local building codes (IRC R502.5.1, R703.1). A permit and inspection may be required. If unsure about structural anchoring, consult a structural engineer or experienced contractor.

Stop work immediately. This ledger connection is structurally unsound and violates multiple code provisions (IRC R507.9).

Critical Failures:

1. Brick Veneer ≠ Structure: You cannot lag into brick veneer. It is non-structural cladding. The lags must penetrate the rim board/band joist inside the wall cavity (IRC R507.9.1.3). You likely have only 1"–1.5" of brick penetration into air/mortar.
2. No Flashing: IRC R703.4 & R507.9.1.1 require corrosion-resistant flashing over the ledger and up behind the weather-resistant barrier (WRB). Brick requires a specific "Z-flashing" or counter-flashing detail tucked into a mortar joint (reglet) or behind the WRB. Water will rot the rim board and flood the wall cavity.
3. Wrong Fastener/Spacing: 3/8" lags are undersized for a 12' joist span (tributary load ~600+ plf). IRC Table R507.9.1.3(1) requires 1/2" diameter bolts or code-listed structural screws (e.g., LedgerLok, SDWS) spaced per the table (typically 12"–16" o.c. for 12' span, depending on fastener type). 24" o.c. is insufficient.
4. No Washers: Lags/bolts require standard cut washers (IRC R507.9.1.3).

Required Fix (Requires Licensed Pro/Engineering if rim board is damaged):

1. Remove ledger and lags.
2. Verify solid rim board (min 1" EWP or 2x lumber) behind brick. If missing/rotten, remediate from interior or via brick removal.
3. Install self-adhered flashing tape on sheathing/rim board.
4. Mount ledger with 1/2" HDG bolts or code-listed 1/2" structural screws at code-prescribed spacing (check Table R507.9.1.3(1) for your exact joist span/load). Use washers.
5. Install Z-flashing over ledger top, tucked min 1" into mortar joint (grind reglet) or sealed behind WRB/lap siding. Seal fastener heads.
6. Maintain 1/2" gap between ledger and brick for drainage/airflow (IRC R507.9.1.2).

Do not hang joists until this is corrected and inspected.