Sean Wilkins of the Brick Development Association gives specification, design and workmanship tips that will ensure that your brickwork is successful
Despite being used for thousands of years with evidence of their use in the UK dating back to the time of the Roman Empire, clay bricks remain a fundamental ingredient in the construction of modern residential buildings.
With thousands of different styles of bricks available in the UK, the colour, texture and general appearance of brick is the main starting point for narrowing down the specification. Brick is a durable and robust material which is suitable for use anywhere in the UK.
However, for the parts of the UK that are classified as severely exposed to freeze-thaw cycles, it is important to check that the ‘Durability’ category of a brick is F2, and its ‘Soluble Salts’ category is S2. The F2 and S2 categories can be found on the Declaration of Performance, which are available from the manufacturer. These are produced for all bricks available on the UK market as part of the CE marking process.
In addition to the brick specification, it is important to confirm that the mortar specification is appropriate to the exposure conditions. This is done by specifying the proportions of binder (cement and lime) to the amount of sand in the mortar.
How the mortar joint is finished will mostly affect the appearance, but it should be noted that recessed mortar joints are only suitable for sheltered locations. This is because a recessed joint can allow water to sit on the exposed part of the brick, which can impact durability and increase water penetration.
DESIGN
The design of brickwork can influence the durability and performance of the finished building, but also it can affect how the brickwork will weather.
Firstly, the setting out of the brickwork should be to co-ordination dimensions, which are a multiple of the brick size, plus the mortar joints. This will help make sure that mortar joints are kept to acceptable widths and minimise the need for cutting bricks.
One of the joys of brickwork is that the bricks can be arranged in an almost infinite number of ways. Fashions in brickwork are constantly changing, as architects and builders experiment with new ways of using the material, from minimal Scandinavian design to the more recent trend for decorative brickwork. Our website contains a number of projects that could give you inspiration on the design of your self-build brickwork project. There are also a number of short design guides that introduce details, such as ‘hit and miss’ and textured brickwork.
The detailed design for brickwork is a large subject – too much to cover in the space we have here. Historically, the detailed design would have varied due to the local geography and building style. As a general rule, more exposed locations would have overhanging copings, sills and roof eaves to minimise the saturation of brickwork, due to winddriven rain. In severely exposed conditions it is a requirement to use overhanging details to ensure durability and prevent water penetration.
WORKMANSHIP
The success of brickwork is very dependent on the quality of workmanship provided by the bricklayer. Once brickwork is built there is very little appetite to take it down, so it is essential that it is built correctly the first time.
Due to the nature of brickwork being a site-based trade, it can be challenging to manage expectations around the appearance of the finished work. For larger projects, the single most important step is to build a sample panel of brickwork so that all parties can agree to the quality of finish. The sample panel should be at least 1 m2 (60 bricks) and preferably in a location where it can be kept for the duration of the project. If a sample panel is not possible then an area of brickwork should be agreed as the quality benchmark.
Brick is a natural material, which can mean there is a small variation from one pallet to the next. To minimise the possibility of patchy brickwork therefore, bricks should be blended from a minimum of three packs. For more detail on this and a number of other workmanship tips, please see the BDA document ‘Good site practice and workmanship.’
Sean Wilkins is technical manager at the Brick Development Association