The Building Conservation Directory 2023

98 T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 3 | C E L E B R AT I N G 3 0 Y E A R S C AT H E D R A L C O M M U N I C AT I O N S prohibited. Filling all joints in this way will aid overall strength, help to minimise the ingress of destructive water into the core of the wall, and will eliminate potential water reservoirs so the wall dries-out faster. Where old walls are deemed in need of some localised repairs and/or re-pointing, it is important to identify the original mortar so that a compatible lime-based mortar can be prepared. Generally, the new mortar would be expected to have the same ratio of aggregate to lime, and the aggregate should match the original as closely as possible. Look out for particles of old brick or stone in the mix which may have been included to help enhance the mortar. The finish of the joints should also match the immediately surrounding areas or, if obvious, the original profile. TREATMENT OF THE HEADS Of primary importance to the long-term stability of all free-standing brick walls is that the tops, or heads, must always be provided with well-detailed protection in the form of copings or cappings, which are laid in a suitably specified lime-based mortar and jointed flush to avoid hollows: Copings are defined as having a good overhang on either side of the wall – typically 40mm or 1½ inches – with a throat to catch and shed water run-off clear of the brickwork directly below Cappings are usually flush to the width of the wall: but if they do have an overhang this will not have a throat. The functions of copings and cappings are both protective and aesthetic and should follow four main points: A coping of purpose-moulded segmental bricks with throats, to an 1878 free-standing brick wall (All photos: Gerard Lynch) STANDARD CAPPINGS Most cappings finish flush with the faces of the free-standing wall. Unlike copings, there is no ‘throat’ or drip on the underside even where a capping extends beyond the wall face, so rainwater run-off will flow down the brickwork directly below. STANDARD COPINGS All standard copings have a ‘throat’, or ‘throating’, formed on the underside of the overhang to drip rainwater clear of the wall face directly below Feather-edge Coping also known as a ‘once- weathered’ or ‘splayed’ Saddleback Coping also known as ‘twice-weathered’ Half-round Coping Double-cant Capping Double-bullnose Capping Segmental Capping (a less common variation of the half-round capping above) Two Saddleback Cappings: the one on the right overhangs the wall but has no drip or ‘throat’ ‘Half-Round’ Capping 1 Having a slope, for weathering, on the top to shed rainwater quickly 2 Keeping water run-off away from the wall face as much as possible 3 The material used should be durable and resistant to weather action 4 They should contribute positively to the aesthetics of the wall and the vernacular details of the area. TYPES OF COPINGS AND CAPPINGS Since the late 19th century cementitious materials such as artificial stone and concrete have been used for copings and cappings, often replacing earlier materials such as natural stones, terracotta or brick. These earlier materials vary both regionally according to what was available ‘Buttering’ a brick with lime mortar to ensure that there are no pockets of air left in the core of the wall (Diagram: Gerard Lynch)

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