How to Build a Brick Wall — Step-by-Step UK Guide

What You'll Need

Before You Start

• Check your boundary — ensure the wall is on your land. Check deeds or instruct a surveyor if there is any doubt.
• Determine wall height and thickness. Walls over 600mm high in half-brick (102.5mm) thickness need piers at regular intervals for stability.
• Check for underground services — use a CAT scanner before digging the foundation trench.
• Use our Brick Calculator for quantities and our Mortar Calculator for sand and cement volumes.
• Soak bricks before use — dry bricks suck moisture from the mortar too quickly, weakening the bond. Dip them briefly in water; do not soak overnight.

Step-by-Step Instructions

Step 1: Excavate and Pour the Foundation

Mark out the foundation trench using string lines and pegs. Excavate to the required depth (minimum 300mm for low walls, 450mm+ for taller walls). The trench should be at least twice the wall width. Compact the base, then pour a C25 concrete mix to a depth of at least 150mm. Level the top and allow to cure for at least 24 hours — ideally 3-7 days for full strength.

Step 2: Set Out the First Course Dry

Lay the first course of bricks dry (without mortar) along the foundation to check the layout. Aim for full bricks with 10mm joints. Adjust the starting position to minimise cuts. Mark the brick positions on the concrete with pencil.

Step 3: Mix the Mortar

Mix 4 parts building sand to 1 part cement with plasticiser and water. The consistency should be firm but workable — it should hold its shape on the trowel and not slump. Mix in batches you can use within 1-2 hours. Do not re-temper mortar that has started to set.

Step 4: Lay the First Course

Spread a mortar bed 10-12mm thick along the foundation. Place the first brick at one end, pressing it gently into the mortar. Butter the end of the next brick with mortar and push it against the first, squeezing the mortar to a 10mm joint. Continue along the row, checking level and alignment with a spirit level after every 3-4 bricks.

Step 5: Build Up the Corners

Build up the corners (quoins) first, typically 4-5 courses high. Rack back each course to maintain the bond pattern. Use a spirit level to check plumb (vertical) and level (horizontal) at every course. These corners act as reference points for the string line.

Step 6: Run a String Line

Attach a string line to the corners using line blocks. The line should sit at the top of each course as a guide. Fill in the bricks between the corners, keeping each brick level with the string line. Remove excess mortar squeezed from the joints with your trowel.

Step 7: Check Gauge Regularly

Use a gauge rod (a straight batten marked at 75mm intervals — 65mm brick + 10mm joint) to check that courses are rising evenly. Consistent gauge is essential for a professional finish. Adjust mortar bed thickness slightly if needed to stay on gauge.

Step 8: Install DPC

At 150mm above ground level (usually after the second course), install a damp-proof course. This can be a course of engineering bricks or a bitumen DPC strip bedded in mortar. The DPC prevents ground moisture from rising into the wall.

Step 9: Point the Joints

Once the mortar is firm but not hard (thumbprint-firm, usually 2-4 hours after laying), finish the joints with a brick jointer. For a weather-struck joint, angle the trowel to create a slope that sheds water. For a bucket-handle joint, run a rounded jointer along each joint. Brush off excess mortar with a soft brush.

Step 10: Cap the Wall

Finish the top of the wall with coping stones, capping bricks or a double course of engineering bricks. The coping should overhang the wall face by 25-40mm on each side with a drip groove to shed rainwater away from the wall face. Bed copings on a full mortar bed and point all joints.

Common Mistakes to Avoid

• Inadequate foundation: A wall without a proper foundation will crack and lean. Never build on topsoil or loose ground.
• Inconsistent joints: Joints that vary in thickness look poor and weaken the wall. Aim for 10mm joints throughout.
• Working in freezing weather: Mortar does not set properly below 3°C. Cover new brickwork with hessian if frost is forecast, and do not lay bricks if temperatures will drop below freezing within 48 hours.
• Not checking plumb: A wall that is not plumb leans and will eventually fail. Check every course with a spirit level.
• Missing piers: Half-brick walls over 600mm high need intermediate piers for lateral stability. Space piers at a maximum of 3m apart.

Cost Estimate (2026 UK Prices)

Use our Brick Calculator and Mortar Calculator for exact quantities for your project.