Grey Brick Slips

What Makes a Brick Slip Grey?

So in terms of brick slips, a simple answer is that the bricks that these slips are cut from are either grey themselves, or have grey applications on them meaning the faces we cut off to use as tiles are the same.

Primarily the way bricks come to be completely grey is based on the mineral composition of the clay used. Grey bricks come from clay with extremely low iron content, meaning the redness you may associate with brick does not develop. This then needs to be enhanced by other additives such as manganese dioxide or even charcoal, which are added in production.

The other aspect is the firing temperature of the bricks- light colours are much better produced by slightly lower temperatures- around 1,000 degrees Celsius as opposed to 1,500 degrees Celsius for example will produce a lighter grey.

As we've come to understand more about firing bricks across the last century, we are able to manipulate the mineral content, firing length and temperature to get specific outcomes in colour, pattern and texture. However, brick is still crafted from natural clay so natural variation is always present.

How Are They Made?

Our range of grey brick slips are mostly cut from full bricks. This means that a 'stock brick' i.e one pushed into a cuboid mould will have the character, specifically creasing and imperfect cuboid shape, created by that amount of clay being pressed. Once the brick is fired we can then cut each side off the brick to create 2 brick slips.

Our reclaimed collection has extra processes applied after the brick is made (but before cutting). They go through a tumbling process (like a big cement mixer) to not only misshape the bricks, but with application of slurries for some blends to create a more weathered look- this application is what creates the grey variants in our otherwise cream blend 10.

 Our contemporary range is a little different. Because they are meant to be perfectly sharp edged, they are simply extruded into the shape of a brick slip already, this economises the amount of clay and the amount of energy used to fire them. They are engobed with their colour to provide a baked in consistent shade.

How Are They Different From Each Other?

The temperature of firing, oxygen levels, length of firing and type/quantity of minerals present mean that there is a variation in colour between each blend, and the slips within each blend too. Each brick type is made to satisfy a different colour palette, and they aren't all completely grey- or even white brick beneath the surface.

Things To Be Aware of With Grey Brick Slips

The grey variations will differ- blend 10 has a more cream base with grey accents, whereas blend 16 is a pure mid-grey.

It's also important to note that when wet they will appear much darker, and can appear more monotone as salts won't show, which create the lighter shades.

With a light colour the mortar makes a much larger impact than on darker shades.

See below the effect that the different mortar colours can have on our grey brick slips.