Brick Dimensions & Block Wall Calculator: A Complete DIY Guide

Building or repairing a brick wall requires careful planning, particularly in calculating the necessary materials. Whether you are constructing a garden wall or repairing an older structure, knowing how many bricks, blocks, and the amount of mortar required is essential to ensure a successful project.

This guide will provide clear steps, practical examples, and useful resources to help you complete your project with ease.

How Many Bricks Do I Need For A Wall?

If you are attempting a do-it-yourself wall or repair then you will need to calculate material quantities and for that you will have to work out how many bricks, blocks and mortar necessary for the job.

The average house brick dimensions are standard for anything built after 1965 but if your house or garden wall was constructed before that then you will have bricks based on the imperial brick dimensions.

We hope to be able to help you to calculate the exact number of standard house bricks and concrete blocks you will need, and you should always allow for damages and breakages.

Bricks calculator

Metric and Imperial Brick Dimensions

The imperial sized brick comes in a number of sizes and depending on when your house was built the size may vary.

The metric brick is a standard size used in modern construction in the UK.

Can You Still Buy Imperial Sized Bricks

Yes you can and they are easier than you would imagine to find. Reclamation yards will have almost every style of brick imaginable and some of the builders’ merchant such as Jewson even make a modern version Imperial Bricks Handmade Reclamation Red Brick 73mm (jewson.co.uk)

Building Your Own Wall

To the novice builder or even those who are willing to have a go at anything do-it-yourself then knowing the quantities needed to build a brick wall is essential so we have a guide for you.

Even if you are trying to match and existing brick wall on a Georgian or Victorian house we have the calculations you will need.

BRICK QUANTITIES (Metric)

BRICK QUANTITIES (Imperial)

Building Blocks

Most building blocks for an exterior wall in the UK will be formed from concrete and are always in metric sizes.

In the UK, most concrete blocks have a face size of 440mm in length and 215mm in height. When used with a 10mm wide mortar joint, this face size for blocks coordinates with the standard brick face size of 215mm length and 65mm height. The thickness of blocks varies from 75mm to 215mm. 

Be aware that these blocks are relatively heavy at 15kg and require a drier mortar than your standard brick.

Using block and render is comparatively cheaper than using bricks and also more time-efficient. These blocks are equivalent to two brick lengths and three brick heights (i.e. a total of six bricks).

BLOCK QUANTITIES

Mortar

Mortar or sand and cement, to the novice, are what you need to, in essence, stick the brick and blocks together for your wall.

The typical ratio of sand to cement is 5:1, as this will be adhesive enough and give the mustard colour of the most common mortar joints.

If you have darker bricks, you can always purchase a cement dye Products | Bostik UK that will blend well with your brickwork.

The tables above will help you determine how much mortar is needed for brickwork and blockwork per cubic metre.

How to Calculate Wall Size

Square Metres (m²): Multiply the length of the wall by its height.

• Example: A wall 2.5 m long and 4.5 m high equals 11.25 m².

Cubic Metres (m³): Multiply the length, width, and height of the wall.

• Example: A wall 2.5 m long, 0.5 m wide, and 3.5 m high equals 5.625 m³

Do-It-Yourself Can Be Easy

If you are taking on the challenge of building your own wall or simply repairing a wall that needs it, then getting the quantity of materials right will save you time and money, and if you are that person that likes DIY, then you probably have a tight budget to stick to.

Building Your Wall

Step-by-Step Instructions

1. Prepare the Foundation: Ensure a level, stable base for the wall.
2. Lay the Mortar: Use a 5:1 sand-to-cement ratio for standard mortar. For darker bricks, consider adding a cement dye for aesthetic consistency.
3. Start with Corners: Lay corner bricks or blocks first, using a spirit level to ensure alignment.
4. Build in Layers: Work row by row, ensuring even spacing (10 mm joints are standard).

Common Issues and Solutions

Why Do Walls Sag or Crack?

• Frequent Use: Repeated pressure or environmental factors can weaken the mortar.
• Gravity: Weight can cause gradual misalignment.

Troubleshooting

• Warped Bricks/Blocks: Replace damaged units.
• Weak Mortar: Repoint the wall with fresh mortar for reinforcement.

Final Tips for DIY Builders

• Use a Spirit Level: Precise alignment improves both aesthetics and durability.
• Measure Twice, Cut Once: Double-check all dimensions before purchasing materials.
• Don’t Rush: Take your time to ensure quality craftsmanship.

When Did Humans Invent Bricks?

Bricks date back to 7000 BC, which makes them one of the oldest known building materials. They were discovered in southern Turkey at the site of an ancient settlement around the city of Jericho. The first bricks, made in areas with warm climates, were mud bricks dried in the sun for hardening.

Why Are There So Many Imperial Brick Dimensions?

In the days when bricks were made with Imperial measurements there wasn’t any standard sizing so different manufacturers would make bricks in whichever size they chose.

Bricks made in Sussex would often be a different size to those made in Kent.

It wasn’t until 1965 when bricks were made to metric measurements that all manufacturers and brickworks made the same sized brick.

Brick sizes have changed significantly across different time periods in the UK, with imperial brick sizes used until recently. The metric system was adopted in 1965 (metric brick size is 215 x 102.5 x 65mm) and is now the standard.