[Working detail 05.05.11] Projecting stair enclosure for Sheffield residential scheme
The elevations at Cemetery Road are heightened through judicious use of a palette of diverse but complementary cladding and walling materials.
These comprise rough-hewn locally sourced stone on dual-skin masonry, rendered insulation on a block substrate, as well as black-stained and pre-weathered zinc cladding on metal-stud substrates.
The most unusual cladding, and perhaps the signature of the scheme, is the black stained batten and board cladding used to articulate a number of elements of the building including the projecting stair/balcony to the western townhouses. This evolved from an interest in traditional Scandinavian domestic architecture where timber-framed houses historically are finished with rough-sawn 200mm boards with a batten fixed over the joint between each board.
This would typically be finished in oxide red or black paint. We were aware that use of this authentic detail was beyond the budget. So we evolved a facsimile detail that could deliver the desired aesthetic. Initially this proposed substituting the vertical 200mm boards with stained WBP plywood, with battens overlaid. However the ply took the stain unevenly and the client was concerned about its durability.
The final solution was to retain the plywood, fixed back to the Metsec metal-stud framing, but to overlay this with a pre-stained cement fibre board. This took the stain well and is deemed durable for external use for up to 30 years. The battens run vertically in a structured randomness but always overlap the joints and fixings of the boards beneath. The vertical joints between the boards are fitted with a Neoprene strip as a precautionary weatherproofing measure.
Christopher Ash, director, Project Orange
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