How to lay double brick walls

What is double brick construction in Australia?

🧱 Laying Double Brick Walls — Professional Trade Guide

Double brick construction involves building two separate masonry leaves with a cavity between them, tied together with corrosion-resistant wall ties to provide structural stability, moisture management and thermal performance. In Australian practice, correct set-out, cavity control, tie placement, damp-proofing and sequencing are critical to comply with AS 3700 Masonry Structures, NCC requirements and relevant state-based building controls.

What skill level is required for laying double brick walls?

Advanced — Estimated time: 2–5 days depending on wall length, height, openings, articulation joints and site access

What tools are essential for laying double brick walls?

🔧 Tools Required

What materials are needed for double brick wall construction?

Safety Requirements

⚠️ Safety

Step-by-Step Guide

Step 1: Set out the wall and confirm structural details

1️⃣ Set-Out and Documentation Check

Confirm all drawings, engineering details, footing dimensions, wall thicknesses, cavity widths, articulation joints, tie schedules, openings and lintel sizes before laying begins. Double brick walls are commonly formed from two 110 mm leaves with a cavity typically in the order of 40 mm–60 mm, but the actual cavity must match the project documents and exposure classification.

Transfer datum levels from the slab or footing and mark all corners, returns, piers, openings and control joints. Check that footing width and bearing are suitable for the total wall thickness and loads. On reactive sites or articulated masonry systems, confirm joint spacing and movement detailing exactly to the engineer’s and manufacturer’s requirements.

Use a gauge rod to establish course heights, allowing for brick size plus mortar bed. Check modular set-out at openings to minimise awkward cuts and maintain bond.

Step 2: Prepare the base and install damp-proofing

2️⃣ Base Preparation and DPC Installation

Ensure the slab rebate or footing surface is clean, level and free from laitance, mud or loose material. Any significant level variation should be corrected before bricklaying starts; do not attempt to absorb major discrepancies in bed joints.

Install the damp-proof course and base flashings as detailed. In cavity masonry, the flashing must direct any moisture in the cavity toward the external face and weepholes. Keep the DPC correctly lapped, unpunctured where possible and turned up/down in accordance with the detail.

Mark the inside and outside leaf positions clearly so the cavity remains consistent along the full wall run.

Step 3: Mix mortar to suit the brickwork application

3️⃣ Mortar Selection and Mixing

Use a mortar compatible with the brick type, exposure conditions and specification. For site mixes, a general bricklaying mortar may vary depending on exposure and workability requirements; follow the project specification or mortar manufacturer guidance rather than using a one-size-fits-all mix.

Where a general-purpose mix is nominated for associated works, a common reference is 1:2:3. For higher structural applications where specified, a mix such as 1:1.5:2.5 may be used, but structural masonry mortar should always align with engineering and specification requirements.

Mix only enough mortar to maintain consistent workability without excessive retempering. Mortar should be plastic, cohesive and able to support brick units without slumping. Keep colour and consistency uniform across visible facework.

Step 4: Build and plumb the leads

4️⃣ Corner Leads and Initial Courses

Build corner leads for both leaves first, typically 4–6 courses high, checking plumb, level and gauge continuously. The leads establish the wall’s line, bond and cavity width, so accuracy here controls the whole job.

Lay the first course carefully on a full, even bed. Fully bed perpends and maintain consistent joint thickness to specification, commonly around 10 mm unless project requirements differ. Use the gauge rod at every course and regularly measure cavity width between leaves.

For face brickwork, select bricks to maintain colour blend and avoid clustering of shade variations.

Step 5: Run both leaves up together in sequence

5️⃣ Sequencing the Inner and Outer Leaves

Run the inner and outer leaves progressively together rather than completing one leaf too far ahead of the other. Keeping the leaves within a manageable height difference improves tie installation, cavity cleaning and line control.

Stretch lines between leads for each leaf and lay to the line, not by eye. Maintain full bed joints and solid perpends unless a specific joint profile or drainage detail requires otherwise. Frequently check for:

Stretcher bond is the most common arrangement in modern double brick construction, though project documents may call for alternative bond treatments in visible facework.

Step 6: Install wall ties at the correct spacing

6️⃣ Wall Tie Placement and Fixing

Install wall ties to the type, material and spacing nominated in the drawings and AS 3700 exposure requirements. In Australian practice, ties are commonly galvanised or stainless steel depending on corrosion environment, with stainless often preferred in coastal or severe exposure zones.

Ties should be laid with a slight fall toward the external leaf where required by the proprietary system so moisture is not directed inward. Place ties as work proceeds, ensuring embedment into both mortar joints is adequate and that mortar fully surrounds the tie.

Increase tie density at:

Do not allow mortar droppings to bridge the cavity or sit heavily on ties, as this compromises drainage and can transfer moisture.

Step 7: Maintain a clean and unobstructed cavity

7️⃣ Cavity Control and Moisture Management

Keep the cavity free of mortar dags and debris at all times. Use cavity battens/boards to catch droppings as the wall rises, removing and cleaning them progressively. A blocked cavity can lead to moisture tracking across to the internal leaf.

Install flashings, weepholes and vents exactly as detailed. Weepholes are generally placed at the base of the outer leaf and above openings where flashing is present, at centres nominated by the documentation or manufacturer. Ensure the weephole path is not blocked by mortar.

This stage is critical in exposed Australian conditions, especially in high rainfall or coastal zones.

Step 8: Form openings, install lintels and continue bond

8️⃣ Openings, Lintels and Returns

Set out window and door openings carefully to maintain coursing and minimise cuts. Install lintels level, with correct end bearing to the engineer’s or manufacturer’s detail. Ensure cavity flashings above lintels discharge to the external face via weepholes.

Maintain tie placement around reveals and openings, usually at closer centres as specified. Check jamb plumb and sill levels before proceeding above openings.

At returns and junctions, preserve the specified bond and tie arrangement. Any deviation at returns can create cracking, poor alignment and structural non-compliance.

Step 9: Install articulation and movement joints

9️⃣ Movement Control

Double brickwork requires movement joints in the locations nominated on the plans and in accordance with articulated masonry principles. Install articulation joints plumb, full height and clear of mortar bridging.

Use approved compressible filler, backing rod and sealant as specified. Ties crossing movement joints must be the correct debonded or movement-capable type where required. Do not hard-pack articulation joints with mortar.

Failure to provide proper movement accommodation is a common cause of masonry cracking on Australian sites, particularly on reactive soils.

Step 10: Finish joints and clean down correctly

🔟 Joint Finishing and Facework Presentation

Tool joints at the correct time once the mortar has thumbprint firmness. Common external finishes include ironed/concave joints for improved weather resistance. Keep joint profile uniform over the full wall area.

Brush off loose mortar as you go. Avoid smearing face bricks with wet mortar, especially on textured or porous units. Use approved cleaning methods only after mortar has cured sufficiently, and always test brick cleaner in an inconspicuous area first.

Check the final wall for:

Common Mistakes to Avoid

Pro Tips

💡 Use a dedicated gauge rod for the exact brick being laid on the project. Small dimensional variations between manufacturers can throw out head heights quickly.

💡 Keep both leaves within a few courses of each other. This improves productivity, tie accuracy and cavity cleanliness.

💡 In facework, blend bricks from at least 3–4 packs at once to avoid colour banding.

💡 Use cavity boards from the first course upward rather than trying to clean hardened droppings later.

💡 In coastal and high-exposure environments, stainless steel ties and accessories often save call-backs and durability issues even where galvanised products may be minimally acceptable.

💡 For large projects, hire rather than purchase masonry scaffold components, brick saws and mixers unless utilisation rates justify ownership. For occasional or short-duration work, hire is usually more economical and reduces maintenance/compliance burden.

Recommended Tools

🔧 Recommended Tools