The strategy of "open building" can be traced back to European and Japanese roots. While it has been widely adopted in those parts of the world, it is only relatively recently beginning to see any use in North America. However, an increased interest in pre-fabricated construction is helping to expand awareness of this approach to building.
The principle is to maintain a separation between the different aspects of the building in order to be able to make repairs and do upgrades with a minimum of interference with other elements of the building. Open building stipulates separate zones or chases for different functions and services. This will, for example, make it easier to change plumbing systems without needing to repair other systems that cross or interfere with access to the necessary parts of the plumbing system.
Open building also makes construction easier by minimizing the interference between different systems, so that the installation of different systems can take place at the same time, rather than needing to be staggered one after another. With each trade and system given its own designated area, the builders (and also the future remodelers or repairers) of those systems can do their work with much less concern about damaging other elements of the building.
Open building lays out six "layers" with different lifespans. They are:
- Site – the location; building site itself. Timeless duration
- Structure – the framework; the "bones" of the building. 100 to 300 year lifespan
- Skin – the cladding. 40 to 100 year lifespan
- Space plan – the interior partition walls. 10 to 30 year life
- Services – electrical, plumbing, mechanical, and heating/ventillation systems. Updated every 1 to 10 years
- Stuff – belongings and furnishings. Can change monthly
Open building is often incorporated into pre-fab systems. Concentrating all of the plumbing elements in one area, for example, helps to put all elements of that system in one area for easier repair access. It also serves to reduce the amount of plumbing material needed. If all water uses are concentrated in one area, there is less piping needed which can mean a reduction in the amount of copper or other material used in the construction. The benefits of engineered construction with pre-fabrication, rather than having all of the installation of the services done on-site, can make for better use of materials and better buildings.
Taken to its extreme, however, open building can become restrictive, forcing configurations on the building that do not serve the needs of the inhabitants. If other parts of the plan are forced into awkward configurations in order to accommodate the structure of open building, then the savings in that one area may be lost in other areas. However, there can be benefits to understanding open building even without wholly embracing the open building system as the chief principle for constructing a building. Looking at the building with an eye to the life cycle of the different systems can lead to a better building, and can help reduce later problems.
Buildings need to be built to meet immediate needs. But they also need to be constructed in a way that future needs and changes to the building are also given consideration. Much in the same way that we need to conserve resources for the use of future generations, the buildings we build today will also be used and re-used well into the future, and a longer-term approach to building is another part of building green.
Article: Reinventing the House (Fine Homebuilding reprint – PDF)