Brick Slip Dimensions – Standard and non-standard sizes

Understanding brick slip dimensions and coverage means you can order the right amount without the guesswork.

No one wants to near the end of an install and find you’re a few slips short, or stuck with far too many left over.

To help, we’ve put together this guide covering standard UK sizes, imperial options, and how to work out your quantities.

So, let’s get started.

 

What are the standard brick slip dimensions?

The standard UK brick slip dimensions are:

215mm (length) x 65mm (height) x 20mm (depth).

The face size – 215mm x 65mm – matches the standard metric brick size used extensively throughout the UK.

Though 20mm is the standard average, the depth (also referred to as thickness) can vary from 10-30mm depending on the intended application (internal or external) and supplier you’re purchasing from.

 

What are the standard brick slip corner dimensions?

The standard brick slip corner dimensions are:

215mm (length) x 65mm (height) x 20mm (depth), with a 102.5mm return.

The size is the same as a metric size brick, cut to a 20mm thickness.

 

Imperial brick slips sizes

The typical size for imperial brick slips is 228mm (length) x 68mm (height) x 20mm (depth), though sizes can differ slightly depending on the supplier.

Imperial size brick slips are often used for matching up to existing brickwork for extensions and renovations.

 

Other brick slips sizes

Aside from imperial and standard metric size, there are thinner brick slip options available.

Linear (also known as long format) brick slips don’t have a standard size. They vary greatly in sizes depending on the manufacturer and the intended application.

Here’s an approximate guide to the sizes:

Dimension	Size (mm)
Length	240 – 500mm
Height	46 – 60mm
Width	20mm average

 

 

How thick are brick slips?

Brick slips are typically around 20mm thick (that’s the width measurement), but you may find a wide range of sizes from different suppliers.

Some can be as thin as 7mm, and others as thick as 30mm or more.

How thick your brick slips need to be depends on how you’re planning to apply them to your wall.

This measurement impacts their weight and how they’ll either attach to the wall surface or fit in your chosen installation system.

We’ll go through each type with you.

 

Internal application

For applying brick slips directly to internal walls, a thickness of 10-20mm is generally recommended.

This range ensures the slips aren’t too heavy for the adhesive to hold securely, whilst also preventing excessive weight load on your wall.

It’s also worth noting that very thin slips (especially handmade) are more fragile and prone to breakages when cutting and applying. If you are ordering thinner brick slips, we’d suggest increasing the quantity/percentage you add on for wastage.

 

External and commercial installation

For external and commercial use, thicker slips are often specified.

The thickness of the brick slips depends on the substrate (wall you’re attaching to) and cladding system being used.

To give you a quick guide:

Type of brick slip cladding system	Brick slip thickness
EWI (external wall insulation) systems	Approx. 15 – 20mm
Mechanical systems	Approx. 20 – 28mm
GRC and precast concrete systems	Approx. 20mm

 

No matter which system you’re intending to use, always check the system manufacturer’s guidance for brick slip size and weight substrate loading limits.

 

Brick slips dimensions and coverage – quick reference

Now you understand brick slip dimensions, you’ll probably want to know how many you’ll need for your project.

We’ll run through square metre coverage and how to measure the quantity for your wall, but first here’s a quick reference guide for some popular sizes.

Brick slip size (length x height)	Coverage per 1m² (10mm mortar joint)	Coverage plus 10% wastage	Brick slip type
215 x 65mm	60	66	Metric
228 x 68mm	54	60	Imperial
230 x 68mm	54	60	Imperial
228 x 73mm	51	57	Imperial
230 x 73mm	51	57	Imperial
228 x 75mm	50	55	Imperial
230 x 75mm	50	55	Imperial

All figures assume a 10mm mortar joint with slips laid in a stretcher bond.

If you want a basic guide on calculations for other brick bonds, take a look at this brick calculator. It’ll give you a brick quantity, but you can use it for brick slips too!

 

How many brick slips per m²

For standard metric size brick slips (215 x 65mm) with a 10mm mortar joint, you will need 60 slips per square metre (1m²).

To factor in wastage – which is excess for cuts, mistakes or breaks – you need to add on 5-10%.

So, the total you’ll need including wastage is 63-66 slips.

It’s also worth noting that brick slips are usually supplied in packs with a specified metre square (m²) coverage, so you’ll probably need to order to the nearest pack size.

 

How to calculate brick slips per metre square (1m²)

The formula for calculating brick slip coverage per one square metre (1m²) is:

1 ÷ [((slip length + horizontal mortar joint) ÷ 1000) x ((slip height + vertical mortar joint) ÷1000)]

 

In practice, for a metric size brick slip with a standard 10mm mortar joint, this calculation looks like:

1 ÷ [((215mm + 10mm) ÷ 1000) x ((65mm + 10mm) ÷ 1000)]
1 ÷ [(225mm ÷ 1000) x (75mm ÷ 1000)]
1 ÷ [0.225 x 0.075]
1 ÷ 0.016875 = 59.26

Rounded to the nearest whole number = 60

 

If this looks a little complex, or you’re using imperial or linear size brick slips (i.e. not metric size), we’ll go through how to calculate how many slips you’ll need step by step.

We’ll use a slip size of 228mm x 68mm as an example.

1. Start with brick slip dimensions
   Length: 228mm
   Height: 68mm
2. Add the mortar joint to each dimension
   The standard mortar joint size is 10mm
   Each slip ‘owns’ the one mortar joint on one length and side
   The brick slip, plus the mortar joint is called the module size
   Module length: 228mm + 10mm = 238mm
   Module height: 68mm + 10mm = 78mm
3. Convert module dimension to square metres (m²)
   Divide by 1000
   Module length: 238mm ÷ 1000 = 0.238
   Module height: 78mm ÷ 1000 = 0.078
4. Calculate the area coverage of one brick slip in m²
   Multiply the length by the height
   Module area: 0.238 x 0.078 = 0.018564m²
5. Divide a full square metre (1m²) by the module (brick slip plus mortar) area
   Brick slips per 1m²: 1 ÷ 0.018564 = 53.87
6. Round up to the nearest whole number (1 slip)
   53.87 rounded up = 54 slips
7. Add extra for size tolerances and wastage allowance
   5% wastage = 54 + 5% = 57 slips
   10% wastage = 54 + 10% = 60 slips

 

How to measure for brick slips (calculate how many you need)

Here’s how to measure a wall for brick slips and calculate how many you need. We’ll use an example wall size of 5.2m x 2.4m, with one window.

Calculate quantity of brick slips required

1. Start with the width and height of the wall
   Width: 5.2m
   Height: 2.4m
2. Calculate the area of the wall (m²)
   Multiply the width and height together
   Area: 5.2m x 2.4m = 12.48m²
3. Subtract the area of any windows and doors
   Window: 1.2m wide x 1.0m high = 1.2m²
   Coverage area: 12.48m² – 1.2m² = 11.28m²
4. Calculate the quantity of slips
   Multiply the coverage area by the quantity of slips required per metre square (1m²)
   If the slips are metric use the quantity of 60.
   For any other size, calculate how many slips you’ll need using the calculation method in the previous section ‘How to calculate brick slips per metre square (1m²)’
   Quantity required: 11.28m² x 60 slips/m² = 676.8
5. Round up to the nearest whole number
   676.8 rounded up = 677 slips
6. Add extra for size tolerances and wastage allowance
   5% wastage = 677 + 5% = 711 slips
   10% wastage = 677 + 10% = 745 slips

 

Calculate quantity of brick slip corners required

If you’re cladding around an external corner, you’ll need to measure your wall for brick slips corners and order these separately.

Here’s how to it:

1. Measure the vertical length of the corner(s) to be cladded in linear metres (m)
   We’ll use 2.4m for this example
2. Add the mortar joint measurement to the brick slip height dimension
   The standard mortar joint size is 10mm
   If the slips are metric size use the 65mm height dimension
   For any other size, check the height of an individual slip
   Module height: 65mm height + 10mm = 75mm
3. Convert module dimension to square metres (m²)
   Divide by 1000
   Module height: 75mm ÷ 1000 = 0.075
4. Divide a linear metre (1m) by the module (brick slip height plus mortar)
   Brick slip corners per 1 linear metre: 1 ÷ 0.075 = 13.33
5. Calculate the quantity of brick slip corners
   Multiply the linear metre coverage by the quantity of slips required per linear metre (1m)
   Quantity required: 2.4m x 13.33 corners/m = 31.93
6. Round up to the nearest whole number (1 slip)
   31.93 rounded up = 32 brick slips corners
7. Add extra for size tolerances and wastage allowance
   5% wastage = 32 + 5% = 34 brick slips corners
   10% wastage = 32 + 10% = 36 brick slip corners

Please note, all of these examples give you the basic calculations for standard walls, window and door openings, and corners as a general guide only.

 

Brick slip size tolerance

While we’re talking about calculating your brick slip quantities, it’s worth mentioning that bricks, and subsequently brick slips, have size tolerances.

A size tolerance is a permitted amount that the actual size may differ from the manufacturer-stated (nominal) dimensions.

It’s typically expressed as ± millimetres to indicate how much smaller or larger the dimensions can be while still meeting the specified size.

You don’t need to worry about tolerances with installation however, experienced contractors will account for them.

 

Find the right brick slips for your project

For all brick slip applications, whether internal or external, you’ll need to make sure you’re choosing the right size for the job.

For most projects, the most convenient and widely available option is standard metric size. Though if you’re working in a conservation area or matching up to old brickwork, you may need to use imperial size.

Now you understand brick slip dimensions and the basics of measuring up, we’d love to tempt you with a look at our brick slip ranges.

We offer brick slips for variety of systems available depending on the intended application, such as:

• Mechanical systems
• External wall insulation (EWI)
• Glass reinforced concrete (GRC) and precast concrete

Feel free to request samples, or if you need some help choosing we’d love to hear from you.