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Protecting decorative projecting brickwork


Projecting brickwork is a popular design feature on masonry building envelopes. However, the resulting inconsistent cavity depths can add complexity when ensuring structures’ passive fire protection – Graham Laws of Siderise Insulation explains more, and describes solutions


M


asonry finishes have long been a desirable facade choice for all kinds of buildings around the


world. Its robust properties and earthy colours lend a sense of safety, solidity and shelter. Aesthetically, beyond the wide range of textures and sizes it offers, brickwork can also be laid offset to create projecting bands or shapes to add interest to large elevations or around windows and doors. However, the inconsistent cavity depth this creates can be a challenge to effectively protect using standard passive fire protection cavity barriers.


Inconsistent cavities


It is a legal requirement in line with BS 9991 for steel-framed masonry constructions with a ventilation cavity to include vertical and horizontal cavity barriers and fire stops, even if the cavity is


ADF NOVEMBER 2021


fully filled with A1 rated (non-combustible) insulation. These are blocks of fire-resistant material that seal the cavity and prevent fire, smoke and heat spreading up the facade and into different building compartments. On a typical build up with a consistent cavity depth, these will be standard full-fill products that are installed between the inner leaf and masonry wall to effectively seal off the cavity. Cavities that vary in depth are more complex, as a full-fill cavity barrier will be unable to meet the masonry leaf and therefore close the gap. For straightforward applications, it may be possible to simply notch a standard full-fill barrier, so it fills the cavity, or to place a board into the gap to flatten out the irregularity. However, this is more difficult to do for more complex and increasingly popular brickwork patterns. The accepted market solution for


Intumescent cavity barrier solutions are designed to help protect inconsistent cavities


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