Surface-Area-To-Volume Ratio / Building Shape

Surface-Area-To-Volume Ratio / Building Shape


The surface area to volume ratio (S/V) is an important factor for the performance of a building. The greater the surface area, the greater the potential heat gain or loss through it. Consequently, a small S/V ratio implies minimum heat gain and heat loss. In order to minimise unwanted losses and gains through the fabric of a building, it’s desirable to design a compact shape, without articulation.

In theory, the most compact building would be a cube. This configuration may not be acceptable for many reasons, such as restrictions to daylight access, site and neighbouring character, planning regulations or simply personal preferences. However, to minimise heat transfer through the building envelope, the building shape and accordingly the floor plan itself, should be as compact as possible. With straight walls and first floor wall on top of ground floor walls. Deleting the need for additional roofing over nooks and grannies in the ground floor areas that stick out.

When designing your home consider thoughtfully what rooms are really needed. Instead of adding rooms you might need. Create multifunctional rooms, spaces that can be used for more than one function and that can easily adapt to a changing lifestyle.

Unfortunately this design principle isn’t supported by most council, as typically planners do not support straight walls without articulation or sheer double storey walls. We are currently working on a town house development in Kingston Council. In our original design we had all first floor walls sitting on top of the ground floor wall. In order to reduce wall and roof areas and hence to optimise energy efficiency. But regrettably, council forces us to step in the first floor walls. As they call it: to create more interest and articulation.