When we think of materials in architecture we assume that they are mostly joined together in some way with nails, screws, bolts, dowels etc. The construction method may not be obvious when we first see a stone structure. If there is no solid ground under each piece of a stone staircase, how do we explain the support of all that weight? There is opportunity to create magical illusions with stone and this one area in which Architects excel!
Studying the Carlo Scarpa, Olivetti Showroom staircase these last couple of weeks has made me think about how I must approach the next stage of the project (Falmouth University, School of Architecture, RIBA Year 1, ARC140).
Qualities of Stone
First I need to choose my material: Natural stone falls into three groups. igneous, sedimentary and metamorphic. (Ref: Basics materials, Manfred Hegger, Hans Drexler, Martin Zeumer, Birkhauser – Basel 2007)
- Igneous rocks (e.g. granite) are formed directly from liquid magma by cooling. They are particularly strong, hard and largely homogeneous in structure (like bricks).
- Sedimentary rocks (e.g. sandstone) are formed from particles. They can contain cavities, horizontal layers or even animal or vegetable fossils depending on how they were formed. They are less strong that igneous rocks, but easier to work.
- Metamorphic rocks (e.g. slate) emerge from existing rock whose structure is changed by pressure, high temperatures or chemical processes (cavity free with distinctive texture).
The art of balancing stone is something humans love to do. Stone balancer, Michael Grab calls this balancing with ‘Gravity Glue’ in this video. I have actually spent time on the beach achieving some crazy balancing skills with rocks since watching this!
Designing a staircase
So my context is an exterior staircase for a house. I must apply Section K and M of UK Building Regulations and create a masterpiece like Scarpa. In two weeks this is tricky. To make it a little easier I have chosen a house I know well as the base structure for the staircase. I’d noticed that an upper window used to be access to a hay loft and imagined that this could become the main entrance to a reverse level home.
There would be a terrace from which to enjoy the views which can only be seen from the first floor out towards Falmouth in one direction, and Loe Beach to the other. It would include storage under and a ‘living garden’ in certain treads. The main concept would be to balance treads using uniform blocks to reduce cost at same time blending staircase into its environment.
Above all, this would be a staircase that would be more than just average…
Herman Hertzberger once said: “Architects bring the exceptional down to the level of the ordinary instead of rendering the ordinary extraordinary.”Lessons for Students in Architecture,Herman Hertzberger, 010 Publishers, Rotterdam 2009
Due to the technical requirements, the model started in sketchup….
Understanding materials is essential to architecture. So far, we have built a spaghetti bridge to see how weight and materials work together. We have had lecture on brick and have been on a site visit to see how different materials come together in a building.
Fired bricks are one of the longest-lasting and strongest building materials, sometimes referred to as artificial stone, and have been used since circa 4000 BC
I now have the task of cutting blocks of my chosen material for my 1:10 scale model; Corian resembles granite yet is much easier to cut. I can start to build my staircase. Already I have experimented with chalk soap stone blocks and foam.
A few stunning examples of architectural staircases made in stone include:
Once I have perfected the design, the next stage is the drawings. Detailed sections are required to show exactly how my staircase will support itself. Not sure if I will ever look at a staircase in the same way again!