Considerations when specifying special shaped bricks

Special shaped bricks can contribute greatly to the aesthetics of a building, but several factors need to be considered when specifying their inclusion.

When designing a structure incorporating special shaped bricks such as cant, arch and bullnose bricks, Specifiers may have certain expectations relating to the aesthetics of the finished build without fully understanding some of the manufacturing constraints which may affect the final look. This blog highlights how special shapes can complement standard bricks and what to consider to achieve a successful specification.

Colour variations

Special shapes are often manufactured separately to main plant standard squares as they need more attention to detail, longer drying times and more care when firing due to different shapes and volumes of units. They will also normally be fired in a different type of kiln. All of these factors may cause colour variations between the special shapes and standard bricks.

Textural variationsTexture variance in special shaped bricks

Methods of manufacture give standard shaped products their character such as the creased effect in some stocks and drag wire, rusticated or rolled in some extruded. To replicate this on special shapes may mean hand application.
This may result in subtle differences between bricks and special shapes when in work. For example in the picture opposite the drag wire marks on the plinth bricks run horizontal whilst the standard bricks are vertical due to different extrusion processes.

Finished brick faces

In main plant kilns the way products are ‘stacked’ can be a method of achieving certain finishes such as ‘hearting’ or ‘flashing’. To achieve the same effect on the sloping face of an angle, plinth or cant could be impractical or mean the unsafe setting of units in the kiln and therefore differ in their finish. Discussion with the manufacturer should clarify which products may be affected.

Durability

Special shaped bricks such as cills, plinths, cappings and copings tend to in a more exposed position and receive the brunt of the water during wind driven rainfall and therefore are more likely to become saturated. Therefore, only F2 (frost resistant) products are recommended for these locations to ensure longevity.

Left or right handed requirementsLeft or right handed special shaped bricks

Some specials such as cills, plinths and universal joints have a left and right handed version because their shape is asymmetric. Others, if textured, have a right and left handed version if there is a possibility of the product being laid ‘upside down’. This may not matter with a smooth product, but when specifying ‘handed’ textured products, always consult the manufacturer.

What can be done about variations?

When brickwork is viewed from the standard minimum 3m distance, differences between the methods of manufacture should not be noticeable. However, a popular use of special shapes is to specify a different colour or texture to the main brickwork. This shows off the shapes to their fullest and makes an attractive feature.

If complimentary rather than contrasting specials are required, early consultation with the manufacturer will help clarify requirements and expectations.Special shaped bricks as an attractive feature Many special shapes such as plinths and cants can be cut and bonded from main plant products helping reduce potential colour variation and speeding up manufacture and delivery schedules. To achieve the desired finish a combination of resin, dyed to suit the body colour of the brick, together with sand taken from the original product are applied to recreate the original texture and colour.

Our Design & Technical teams offer advice on the performance and properties of all our products by calling 0844 800 4576. Our team of Design Advisors can also offer creative and cost-effective solutions to any design project for architects working with brick and other products from our range.