November 3rd 2021
Not all bricks are made the same. Take engineering bricks for example.
They're almost as common as your standard facing brick but 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? We take a look here.
If you're not already in the know, you'll probably want a few things clearing up.
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/mm^2^ and a water absorption rate of less than 4.5%. These boys are tough.
They're also normally blue, though reds and greys are available too. Classic makes of this 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/mm^2^ and a water absorption rate of less than 7%.
You'll find Class Bs in red, blue, grey and buff predominatly. There are many examples of this category and you shouldn't have any problem getting your hands on a few.
So why would you normally use these bricks over your usual facing bricks?
Well, 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.
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.
To get this supreme strength and durability, they have to go through a very specific manufacturing process.
This involves firing the bricks 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.
So, we mentioned above that 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 too. Again, the low water absorption and durability are the main concerns when building these important structures.
It's not just houses either. British bricks like the ones we mentioned above have been used in some pretty famous structures around the world.
The base of the iconic Empire State Building in New York was built using red Accrington or 'Nori' bricks, which were made not far from the Lancashire town where they get their name.
In some cases, Class A bricks have been used for their colour. The Staffordshire Blue brick in particular has been used in classic buildings such as this old church in the past and can now be seen in modern developments that want to get a distinctive, dark, urban look.
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 major 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 actually provide a more industrial or vintage look.
The fact is, you're always going to need engineering bricks. They're a key part of building a structure. But there is still a bit of choice out there, so make sure you've got the right one for your building project.
If you want to get hold of some engineering bricks, you don't have to look far. Head to our brick library page.
If you need a hand selecting the right brick for you we can also help with that.