We have recently completed the design, manufacture and installation of yet another cantilevered staircase. Our first ever cantilevered staircase was installed in a property in the very British virgin islands over 10 years ago and since then we have undertaken a series of architectural projects incorporating staircases on both sides of the Atlantic
Every one of these has been different not only in terms of design but also from an engineering perspective. The project in the BVI was no exception in that uniquely in our experience to date, we had to factor into our design and calculations very specific site conditions that apply to a property that is located in an earthquake zone.
Less exotic but no less enjoyable, last month saw us completing our latest staircase at a property in East Lothian, Scotland adjacent to the Archerfield Golf links. We were commissioned by AitkenTurnbull, an architectural practice with offices throughout Scotland. The particular technical challenge that we faced in this case was the absence of a load bearing wall above the staircase. Traditionally, the wall above the staircase acts as the downward load for the cantilevered steps. So to balance the loading on the steps in this case we incorporated deeper, heavier treads at the top of the staircase and used the stone apron which had created a wonderful galleried landing to allow us to pin the steps into position.
The staircase itself was fabricated from limestone from the Alcanede quarries of Portugal, a material that is very similar in structure and appearance to Portland stone. Selecting the best blocks of stone to use in the manufacture of a staircase is very important and the material is chosen at source by the quarry master who with the benefit of years of experience and know how handed down over generations, is able to select those blocks that do not contain any fractures. Once the raw material reaches the factory the individual steps are fabricated in accordance with a detailed cutting list identifying the exact size of each step in order and ensuring, where this is a consideration, that the veining found in the blocks continues from one step to the next. The cut steps are closely inspected by our master mason to ensure that there are no structural defects in the material and only then does the process of profiling the steps begin. Once the work has been finished we assemble every staircase at the factory, a process which allows the masons to make any necessary small adjustments to the soffit and mouldings and we can deliver the staircase to site in the certain knowledge that it fits together perfectly.
The individual steps in this particular staircase feature a smooth soffit, a detail which was widely used in staircases of this type during the 19th century and the simple bullnose and cavetto mouldings give the steps an elegant and understated appearance.
We also supplied the steel balustrading and the handrail which was fabricated from American walnut. An unusual feature in the overall design scheme was the juxtaposition of the limestone staircase with a tiled floor in the entrance hall of the property. The tiles used were typical of the colourful detailing originally seen in many late 19th century buildings and provided an unexpected but entirely successful counterpoint to the elegant simplicity of the limestone staircase.
Designing, manufacturing and installing cantilevered staircases is an extremely rewarding field in which to work. Even the most graceful rendering of a proposed staircase fails to do justice to the effect that it has on an entrance hall and the feeling of space and lightness it creates as it progresses upwards through a building. The transformational effect never fails to exceed a client’s expectations and whilst there is a cost attaching to it, we have yet to encounter a client who has questioned the value of their investment in a decorative and practical feature that lies at the core of a building.
Find out more by visiting Chesney’s Architectural website: www.chesneysarchitectural.co.uk