How many bricks do I need per square metre?

For a standard half-brick (single skin) wall, you need approximately 60 bricks per square metre. For a one-brick (double skin) wall, you need 120 bricks per square metre. Always add 10% for wastage.

What is the standard UK brick size?

The standard UK metric brick measures 215mm x 102.5mm x 65mm. With mortar joints (typically 10mm), this becomes 225mm x 112.5mm x 75mm.

How much mortar do I need per 1000 bricks?

Per 1000 bricks, you typically need 1 tonne of sand (0.5 cubic metres), 6-7 bags of 25kg cement (for a 1:5 mix), and 1-2 bottles of plasticiser.

Should I add wastage to my brick calculation?

Yes, always add wastage allowance. Add 5-10% for standard walls, 10-15% for walls with openings like windows and doors, and up to 15% for complex architectural features.

Brick Calculator Guide UK 2025 - How Many Bricks Do I Need?

Planning a brickwork project in the UK? Whether you're building a garden wall, constructing a barbecue surround, or undertaking a larger construction project, accurately calculating the number of bricks you need is essential. Ordering too few means project delays and potential colour matching issues, while ordering too many wastes money and leaves you with excess materials.

This comprehensive guide explains how to calculate brick quantities using UK standard sizes, helping you plan your project efficiently and budget accurately.

Understanding Standard UK Brick Sizes

In the United Kingdom, bricks are manufactured to specific metric dimensions that have been standardised across the industry. Understanding these measurements is crucial for accurate calculations.

Standard UK metric brick dimensions:
Brick only: 215mm (length) × 102.5mm (width) × 65mm (height)
With 10mm mortar joints: 225mm × 112.5mm × 75mm

These standardised dimensions mean approximately 60 bricks cover one square metre in a half-brick wall.

Imperial bricks (used in older UK properties) measure slightly differently at 9" × 4.5" × 3" (approximately 228mm × 114mm × 76mm). If you're matching existing brickwork on a period property, you may need to source imperial-sized bricks from specialist suppliers.

Bricks Per Square Metre by Wall Type

The number of bricks you need varies significantly depending on your wall construction type and bonding pattern. Here's a detailed breakdown:

Wall Type / Bond	Bricks per m²	Typical Use
Half-brick (single skin)	60	Garden walls, internal partitions
One-brick (double skin)	120	External walls, structural walls
Stretcher bond	60	Most common for single-skin walls
English bond	80	Strong, traditional pattern
Flemish bond	79	Decorative, traditional look
Header bond	120	Curved walls, decorative

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Step-by-Step Brick Calculation

Follow these steps to calculate exactly how many bricks you need:

Measure your wall area: Multiply length × height to get square metres
Subtract openings: Deduct the area of any doors, windows, or gates
Multiply by bricks per m²: Use 60 for half-brick, 120 for one-brick walls
Add wastage allowance: Add 5-15% depending on project complexity
Round up to pack sizes: Bricks typically come in packs of 400-500

Common Project Calculations

Here are pre-calculated estimates for popular DIY brickwork projects:

Project Description	Dimensions	Area	Bricks (inc. 10% wastage)
Small garden wall	3m × 1m high	3 m²	198 bricks
Medium garden wall	5m × 1.2m high	6 m²	396 bricks
BBQ surround	Varies	~3 m²	~200 bricks
Single brick pillar	0.5m × 0.5m × 1.5m	3 m²	396 bricks
Raised flower bed	2m × 1m × 0.5m	3 m²	198 bricks

Mortar Requirements

Mortar is essential for laying bricks properly. Here's what you need per 1000 bricks:

Material	Quantity	Notes
Building sand	1 tonne (0.5 m³)	Sharp sand for stronger mortar
Cement (1:5 mix)	6-7 × 25kg bags	OPC or masonry cement
Plasticiser	1-2 bottles	Improves workability
Hydrated lime (optional)	25kg bag	Alternative to plasticiser

Pro tip: For a standard 1:5 mortar mix, combine 1 part cement with 5 parts building sand. Add plasticiser to improve workability and help the mortar stick to bricks more effectively, especially in hot weather.

Wastage Allowance Guidelines

Always add extra bricks to account for cutting, breakages, and mistakes:

Standard straight walls: Add 5-10%
Walls with openings (doors, windows, gates): Add 10-15%
Complex features (curves, arches, steps): Add 15%
Always round up to the nearest pack quantity

Important: Order all your bricks from the same batch to ensure consistent colour matching. Bricks from different batches can have noticeable colour variations that will be visible in your finished wall.

Buying Bricks: What to Consider

When purchasing bricks in the UK, keep these factors in mind:

Pack sizes: Typically 400-500 bricks per pack
Delivery: Factor in delivery costs; bricks are heavy
Frost resistance: Essential for outdoor walls in the UK climate
Engineering bricks: Required below damp-proof course level
Keep spares: Store a few bricks for future repairs

UK Brick Suppliers

Popular UK suppliers include Jewson, Travis Perkins, Wickes, and B&Q. For reclaimed or specialist bricks, try local salvage yards or specialist suppliers like Bricks of Distinction.

Brick Calculation Methodology

Accurate brick calculation requires understanding the relationship between wall area, brick dimensions, and mortar joint thickness. The standard UK brick measures 215mm long by 102.5mm wide by 65mm high. When a 10mm mortar joint is added to the length and height, the effective coursing dimensions become 225mm by 75mm. This means that for a half-brick thick wall (single skin, 102.5mm), you need approximately 60 bricks per square metre of wall face.

For a one-brick thick wall (215mm), the count doubles to approximately 120 bricks per square metre because you are building two interlocking skins. Cavity walls, which are the standard construction method for external walls in the UK, consist of two separate skins with a gap between them, requiring approximately 120 bricks per square metre of wall (60 for each skin). The cavity is typically 50 to 100mm wide and may be partially or fully filled with insulation to meet current Building Regulations thermal requirements.

The waste allowance is a critical factor that many DIY builders underestimate. A standard allowance of 5 percent accounts for broken bricks during delivery and on-site breakage during cutting. For walls with numerous openings, curved features, or decorative bonds that require more cutting, the waste allowance should increase to 10 percent. For projects using reclaimed bricks, which are more variable in size and more prone to breakage, a waste allowance of 15 percent or more may be appropriate. Running short of bricks mid-project is both frustrating and potentially costly, as subsequent batches may have slight colour variations.

Mortar calculation: For every 1,000 standard bricks laid in a half-brick wall, you will need approximately 0.5 cubic metres of mortar. A standard mortar mix for general brickwork is 1 part cement to 5 or 6 parts building sand, with the addition of plasticiser to improve workability. For a small garden wall project requiring 500 bricks, you would need roughly 5 bags of 25kg cement and 1 tonne of building sand, costing approximately £50 to £80 for materials.

UK Building Regulations for Brickwork

Any structural brickwork in the UK must comply with the relevant Building Regulations, and many projects require Building Regulations approval or a building notice before work begins. Garden walls under 1 metre in height generally do not require planning permission or Building Regulations approval, but walls between 1 and 2 metres may need approval, and walls over 2 metres almost certainly will. Boundary walls adjacent to highways have a lower threshold of 1 metre before planning permission is required.

For structural walls forming part of a building, UK Building Regulations specify requirements for foundations, damp-proof courses, cavity construction, insulation, and structural integrity. Part A of the Building Regulations covers structural safety, including requirements for wall thickness, buttressing, and the maximum height-to-thickness ratio. A standard cavity wall for a two-storey house requires an outer leaf of at least 102.5mm, a cavity of at least 50mm, and an inner leaf of either 100mm blockwork or 102.5mm brickwork, with appropriate wall ties at specified intervals.

The choice of brick type must also comply with British Standards, particularly BS EN 771-1 for clay bricks. Below the damp-proof course, engineering bricks with low water absorption (less than 7 percent for Class A, less than 12 percent for Class B) must be used to prevent moisture damage. Facing bricks used above the DPC should have appropriate frost resistance for the exposure level of the site, categorised as F0 (passive exposure), F1 (moderate exposure), or F2 (severe exposure). Most of the UK falls within the moderate to severe exposure categories, meaning frost-resistant bricks are essential for external walls.

Frequently Asked Questions

How many bricks do I need for a garden wall?

A simple garden wall 5 metres long and 1 metre high, built as a single-skin half-brick wall, requires approximately 300 bricks (5m x 1m = 5 square metres, multiplied by 60 bricks per square metre). Adding 5 percent for waste brings the total to 315 bricks. However, a freestanding single-skin wall of this length and height would need brick piers (supporting pillars) at each end and at intervals of no more than 3 metres for structural stability. Each pier requires additional bricks, typically 15 to 20 per metre of height, so two piers would add approximately 30 to 40 bricks to the total.

What is the cheapest brick available in the UK?

Common wirecut bricks are the most affordable option, typically costing £250 to £400 per thousand depending on the supplier, colour, and quantity ordered. Stock bricks with a more rustic appearance cost £400 to £600 per thousand, while handmade bricks for period properties can cost £800 to £1,500 per thousand. Reclaimed bricks vary enormously in price from £400 to £2,000 per thousand depending on age, type, and condition. For budget-conscious projects, purchasing bricks in full pallet loads (typically 400 to 500 bricks per pallet) usually secures the best per-brick price, and comparing prices from multiple merchants can save 20 to 30 percent.

Can I build a brick wall myself or do I need a bricklayer?

Simple garden walls, raised flower beds, and small decorative features are achievable DIY projects for those with basic building skills and patience. However, any structural wall, extension, or wall above 1.2 metres height should be built by a qualified bricklayer. Professional bricklayers in the UK typically charge £350 to £500 per day, or £400 to £600 per thousand bricks laid. Hiring a professional ensures the wall meets Building Regulations, is structurally sound, and has consistent mortar joints and a professional finish. Poorly built walls can be both unsightly and dangerous.

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Do I need planning permission to build a brick wall in the UK?

Planning permission requirements depend on the wall's height and location. Under permitted development rights, you can generally build a wall up to 2 metres high without planning permission, or up to 1 metre if adjacent to a highway used by vehicles. Walls within the curtilage of a listed building always require listed building consent. In conservation areas, additional restrictions may apply, so check with your local planning authority before starting work. Building Regulations approval is separate from planning permission and is required for walls that form part of a building structure. Even for garden walls that do not need planning permission, Building Regulations may still apply if the wall exceeds certain heights or supports a load. Your local council's planning portal provides free guidance specific to your area and property type.

How do I calculate mortar quantity for brickwork in the UK?

For standard 10mm mortar joints with UK-size bricks (215mm x 102.5mm x 65mm), you need approximately 0.043 cubic metres of mortar per square metre of single-skin brickwork. A standard mortar mix for general brickwork is 1:5 (one part cement to five parts building sand) or 1:1:6 (one part cement, one part lime, six parts sand) for a more workable mix. For one square metre of brickwork, you will need roughly 8kg of cement and 40kg of sand. A 25kg bag of cement mixed with building sand makes enough mortar for approximately 3 square metres of brickwork. Always add 10-15% extra for wastage. Pre-mixed mortar is available from UK builders' merchants at approximately £5-8 per 25kg bag, which is convenient for smaller projects.

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James is a Chartered Certified Accountant (ACCA) specialising in UK personal taxation and financial planning. With over 12 years in practice and a background as a former HMRC compliance officer, he brings authoritative insight to complex tax topics.