Part of an old brick viaduct bridge

Engineering Bricks: What Are They Used For?

Brickhuter
1 February 2024

3-minute read

Not all bricks are made the same. Take engineering bricks, for example. They're almost as common as your standard facing brick, but they don't have anywhere near the same variety of styles.

This is partly because you don't tend to pick them for their aesthetic qualities.

Among other things, engineering bricks are used for building foundations and providing structural support. If you're currently undertaking a self-build, you'll probably need some. But maybe you're wondering whether they can be used for anything else?

If you're not already in the know, you'll probably want a few things clearing up - and if you're looking to buy some, we can help with that too.

Shop engineering bricks

What are engineering bricks?

What sets engineering bricks apart is their high compression strength, durability and water absorption. These wire-cut bricks often have a smooth, plain surface and come in two categories: Class A and Class B.

The difference is essentially how tough they are. Class A bricks have a compression strength of 125 N/mm2 and a water absorption rate of less than 4.5%. They are tough. They're also normally blue, though reds and greys are also available. Classic makes include the Staffordshire Smooth Blue, Ketley Blue and Weinerberger Flashed Black.

Class B engineering bricks typically have a slightly smaller compression strength of 75 N/mm2 and a water absorption rate of less than 7%. You'll predominantly find Class Bs in red, blue, grey and buff. There are many examples of this category, and you shouldn't have any problem getting your hands on a few.

These wire-cut bricks often have a smooth, plain surface and come in two categories: Class A and Class B

What makes them different?

So why would you normally use these bricks over your usual facing bricks?

Take your typical house build. One of the most important aspects of a building project is making secure foundations. To build these you need bricks, most of which won't be above ground level.

These bricks need high strength and durability to stand the test of time. You also wouldn't want to waste perfectly nice facing bricks on foundations that are going to be covered up.

Unlike the wide range of textures and levels of porosity found in normal bricks, the low water absorption of engineering bricks means they help to reduce damp and keep a building dry.

And, because they're not used for aesthetic purposes it doesn't matter so much what they look like and are often significantly cheaper than normal facing bricks.

How they're made

To get this supreme strength and durability, the bricks go through a very specific manufacturing process, which involves firing them at a high temperature.

The clay used is also chosen for its durable properties and when fired at a regulated high temperature, the molecular structure hardens. In fact, this is also why Class A bricks are blue. It's not an afterthought.

Blue bricks are normal clay bricks that turn blue as a result of being heated at a high temperature in a low-oxygen environment. This process also gives it an impervious surface.

How they're used

Engineering bricks are ideal for use in building foundations - this is probably the main reason you would come across them.

Typically, you would lay a couple of courses of brick in the footings below ground, and two courses of the same engineering brick above ground. If you look at a lot of houses, you can often see two courses of a different colour at the bottom.

Engineering bricks are also used for building damp-proof courses. A damp-proof course stops moisture from rising in the structure. As we mentioned above, these bricks are ideal as they have a low water absorption.

They've also been used for bridges, canals and tunnels. Again, the low water absorption and durability are the main concerns when building these important structures.

Stacked pallets of grey engineering bricks

Not just practical

So, what about whole houses? Can you make a whole building out of engineering bricks if you wanted to?

Could Class B engineering bricks be used for their look more than their practical properties?

Well, generally, they're not. A standard clay brick, with its unique aesthetic properties, is much better suited to most houses.

The natural weathering that will occur with standard facing bricks is going to lend a much nicer look to a house in years to come than the hard, efficient look of an engineering brick.

That said, there's nothing stopping you and they could be a cheaper way of building if you were happy with the way they look.

Because of their density you may also need to think about how much mortar you're using when bricklaying, but this shouldn't be too much of an issue.

Arguably, if you did want to use them as facing bricks they might be better suited to a garage or shed if you are planning to add something else to your land.

The hard flat surface and defined colour may provide a more industrial or vintage look.


We're here for you

You're always going to need engineering bricks because they're a key material. But there is still a bit of choice out there, so make sure you've got the right one for your project.

And don't forget: whatever you are building, we have a range of services tailored to help you achieve successful brickwork.

Our expert Brick Advisors are standing by to help you match, customise and calculate the exact amount of bricks you need, then source them and find the best price - we'll even arrange delivery too.

Simply let us know what you need, and our experts will do the rest!

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