{"id":25616,"date":"2026-02-11T15:34:52","date_gmt":"2026-02-11T15:34:52","guid":{"rendered":"https:\/\/www.tobermore.co.uk\/professional\/?p=25616"},"modified":"2026-02-11T15:34:52","modified_gmt":"2026-02-11T15:34:52","slug":"mortar-joint-profiles-and-weather-resistance-of-a-facing-brick-wall","status":"publish","type":"post","link":"https:\/\/www.tobermore.co.uk\/professional\/blog\/mortar-joint-profiles-and-weather-resistance-of-a-facing-brick-wall\/","title":{"rendered":"Mortar joint profiles and weather resistance of a facing brick wall\u00a0"},"content":{"rendered":"
Mortar binds\u00a0<\/span>\u200b<\/span><\/span>concrete facing bricks<\/a>\u00a0together. However, it does more than just act as an adhesive.\u00a0<\/span>It provides a bearing pad for the facing bricks, fills gaps, and provides an important barrier to the passage of moisture. On this last point, selecting the correct mortar class for the application is not the only factor in forming a suitable moisture barrier – using the correct mortar joint profile is just as important.<\/span>\u00a0<\/span><\/p>\n Whilst different mortar joints can give a wall made of concrete facing bricks\u00a0<\/span>a\u00a0<\/span>different\u00a0<\/span>aesthetic,<\/span>\u00a0some may not be\u00a0appropriate where\u00a0high exposure to rainfall is likely.<\/span>\u00a0<\/span>In this blog<\/span>,<\/span>\u00a0we will look at some of the\u00a0different types\u00a0of mortar\u00a0<\/span>joints<\/span>\u00a0that can be used and which should be used to enhance\u00a0<\/span>the\u00a0<\/span>weather protection of the finished wall.<\/span>\u00a0<\/span><\/p>\n To get the\u00a0optimum\u00a0finish on mortar joints<\/span>,<\/span>\u00a0the concrete facing bricks should be laid on a full bed of mortar with all joints filled. The specified joint profile should be formed after leaving the mortar to harden slightly.\u00a0<\/span>\u00a0<\/span><\/p>\n Tooling is recommended to compact the joints, improve weather resistance, and reduce shrinkage in the mortar. Joints should be finished depending on the overall visual e\ufb00ect and weathering performance\u00a0required. It is vital that all horizontal and vertical joints\u00a0<\/span>are<\/span>\u00a0compacted and free from voids. Shell bedding should not be used.\u00a0<\/span>\u00a0<\/span><\/p>\n Recessed or flush pointing is not recommended in areas with\u00a0<\/span>high-exposure\u00a0to moisture<\/span>. We shall now explore the mortar joint profiles in more detail to see how their shape affects their suitability to form an effective barrier against water ingress.<\/span>\u00a0<\/span><\/p>\n The joint profiles of mortar in concrete facing bricks make up approximately 17% of the overall wall area<\/span>,<\/span>\u00a0and different joint profiles can affect both the aesthetics and weathering properties of the wall.<\/span>\u00a0<\/span><\/p>\n The surface shape and depth of different mortar joints affect their water resistance and aesthetics<\/span>.\u00a0A<\/span>s a general\u00a0<\/span>rule,<\/span>\u00a0a concave joint reduces water penetration through the joints<\/span>,<\/span>\u00a0whilst raked joints increase the risk.<\/span>\u00a0<\/span><\/p>\n We will look at six mortar joints in more detail.<\/span>\u00a0<\/span><\/p>\n This is the most common joint used in masonry construction. The tooling works the mortar\u00a0<\/span>tightly<\/span>\u00a0into the joint between the facing bricks to form a tight seal that gives this joint its strong water resistance. The brick pattern is emphasised with a concave mortar joint<\/span>,<\/span>\u00a0and small irregularities in laying are concealed.<\/span>\u00a0<\/span><\/p>\n The Vee joint is\u00a0similar to\u00a0the concave joint but has a sharp V-shaped indentation, giving it a more dynamic and modern appearance.\u00a0It\u2019s\u00a0a popular choice for contemporary designs, offering a sleek and stylish finish to brickwork.<\/span>\u00a0<\/span><\/p>\n A flush mortar joint is level with the brick surface and is typically used when walls will be plastered or painted, requiring extra care to make it watertight.\u00a0<\/span>\u00a0<\/span><\/p>\n The weathered (or struck down) joint tapers inward at the top, creating a shadow line and promoting water runoff. Commonly used horizontally, it\u00a0dates back to\u00a0the 19th century. While effective, poor execution can lead to shrinkage and water seepage.\u00a0<\/span>\u00a0<\/span><\/p>\n The struck mortar joint, used horizontally, tapers inward at the base (struck up), opposite to the weathered joint.\u00a0It\u2019s\u00a0mainly used\u00a0for interior walls as it allows water to sit and seep in if exposed. Originating in the 15th century, it was designed to mask irregular bricks by creating one straight edge and blending the mortar into the other.<\/span>\u00a0<\/span><\/p>\n This mortar joint strongly emphasises horizontal joints. It incorporates a ledge to create the horizontal lines, and this ledge will collect rainwater as it runs down the wall. This makes it\u00a0a very poor\u00a0weather joint, so it is not recommended for external walls exposed to the elements.<\/span>\u00a0<\/span><\/p>\n Here is a summary table for mortar joint profiles with an outline of their water resistance and typical use.<\/span><\/span>\u00a0<\/span><\/p>\nWhat is good practice when forming mortar joints on site?<\/span><\/b>\u00a0<\/span><\/h2>\n

What are the different types of mortar <\/span><\/b>joints<\/span><\/b>?<\/span><\/b>\u00a0<\/span><\/h2>\n
\u200b<\/span>\u200b<\/span><\/span>Concave or bucket handle mortar joints<\/span><\/b>\u00a0<\/span><\/h3>\n
Vee mortar joints<\/span><\/b>\u00a0<\/span><\/h3>\n
Flush mortar joints<\/span><\/b>\u00a0<\/span><\/h3>\n
Weathered mortar joints<\/span><\/b>\u00a0<\/span><\/h3>\n
Struck mortar joints<\/span><\/b>\u00a0<\/span><\/h3>\n
Raked or recessed mortar joints<\/span><\/b><\/h3>\n