Attaching a deck ledger board to a brick veneer house is more involved than fixing to a standard timber-clad wall, because the brick is a non-structural cladding — your fixings must pass through it and anchor into the timber framing behind. Done correctly, with proper flashing and approved fixings, a ledger-attached deck is strong, weathertight, and compliant with the NZ Building Code.
Understand the Structure First
Brick veneer in New Zealand is typically a single skin of bricks (around 110 mm thick) tied to a timber-framed wall with brick ties, with a cavity of roughly 25–50 mm between the brick and the framing. This means your ledger fixings must span the brick, the cavity, and the wall framing — often a total depth of 150–200 mm or more before you reach solid timber.
Before you start, confirm:
- The location of the floor joists or rim joist inside the wall (use a stud finder or check your building plans).
- The cavity width (your builder or council may have records, or you can drill a small exploratory hole).
- Whether a building consent is required. Decks over 1.5 m above ground generally require consent; lower decks may qualify as exempt work under Schedule 1 of the Building Act — but the exemptions have specific conditions relating to height, area, and proximity to boundaries — but always confirm with your local council before starting.
Tools and Materials You'll Need
- Treated timber ledger board (H3.2 minimum for ground-level splash zone, H4 if in contact with the ground)
- Heavy-duty structural lag screws or through-bolts (stainless steel or hot-dip galvanised, minimum 12 mm diameter)
- Flashing tape and purpose-made ledger flashing (aluminium or copper)
- Masonry drill bits and a rotary hammer drill
- Spirit level, chalk line, tape measure
- Sealant compatible with your cladding (check manufacturer's data sheet)
- Safety glasses and hearing protection
Step-by-Step Installation
1. Mark the Ledger Position
Snap a chalk line at the correct height. Remember to account for the deck joist depth and finished decking thickness so the deck surface finishes at the right level relative to the interior floor — typically 100–150 mm below the interior floor level to prevent water ingress through the door threshold.
2. Install Flashing First
This is the most critical step for weathertightness. Water must not be allowed to track behind the ledger and into the wall cavity — a leading cause of moisture damage and rot in NZ homes.
- Cut a horizontal slot in the mortar joint immediately above the ledger line, or carefully remove a course of bricks if needed, to tuck flashing behind the brick course.
- Install a continuous Z-flashing or purpose-made ledger flashing that directs water away from the wall. The top edge must be sealed or tucked behind the cladding; the bottom edge must overhang the ledger face.
- Use flashing tape (such as products available from Bunnings or Mitre 10) to seal all penetrations and overlaps. Follow BRANZ guidance on weathertight detailing for ledger connections.
- Never rely on sealant alone as your primary weatherproofing.
3. Drill Through the Brick and Cavity
Using a rotary hammer drill with a long masonry bit, drill pilot holes through the brick at your fixing locations. Fixing points should align with the rim joist or floor framing inside the wall — not just into the cavity or noggins. Typical spacing is every 400–600 mm, staggered in two rows to reduce splitting.
4. Fix the Ledger Board
Hold the ledger in position (get a helper or use temporary props) and drive your stainless steel lag screws or through-bolts through the brick, across the cavity, and into the timber framing. Lag screws should penetrate the framing timber by at least 50–60 mm beyond the cavity.
- Do not rely on fixings into the brick itself — brick veneer is not structural.
- Use stainless steel or hot-dip galvanised fixings throughout; NZ's coastal and humid environments will corrode standard zinc-plated hardware quickly.
- Check the ledger is level as you go.
5. Seal All Penetrations
Once fixed, apply a compatible sealant around each bolt penetration on the face of the brick. This is a secondary measure — your flashing is the primary defence.
Compliance and the NZ Building Code
Deck ledger connections must comply with NZS 3604:2011 (Timber-framed buildings) and the NZ Building Code, particularly Clause E2 (External Moisture). Flashing details are critical to meeting E2 requirements. If your deck requires consent, your plans will need to show the ledger fixing and flashing detail. Check MBIE Building Performance for guidance on consent requirements and acceptable solutions.
When to Call a Professional
While a competent DIYer can tackle a ledger installation, there are situations where you should engage a Licensed Building Practitioner (LBP):
- If the deck requires a building consent — certain restricted building work must be carried out or supervised by an LBP.
- If you're unsure about the wall framing layout or cavity construction.
- If the deck is elevated or attached to a multi-storey home.
- If you notice any existing moisture damage, rot, or cracked mortar around the area.
A qualified deck builder will also know how to detail the flashing correctly for your specific cladding system. You can find experienced local deck builders on tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
