OPEN Building Principles
One of the cornerstones of the OPEN Prototype Initiative is Open Building, developed in part at MIT by John Habraken who headed MIT’s Department of Architecture from 1975 to 1981, and embraced by Kent Larson, who currently heads MIT’s House_n Consortium and Open Source Building Alliance.
These principles have been further refined and expanded on by Tedd Benson, founder of Bensonwood Homes of Walpole, New Hampshire. Bensonwood has been involved with Open Building techniques for nearly three decades. The Open-Built® systems that Bensonwood has developed during the past decade currently represent the state-of-the-art of Open Building in America.
Open Building "layers" the home, disentangling components to create greater access for updating its configuration and/or services. This can extend the useful lifespan of a house from decades to hundreds of years.
"...We are prototyping the future of homebuilding."
The concepts of Open Building provide a framework for a better way to build. The
Open-Built® components, assembled to create the first OPEN Prototype (OPEN_1)
at Crotched Mountain, represent a unique and ground-breaking expression
of Open Building in America. The systems and components will not be
perfect, but that is what makes prototypes so educational and
useful. We will apply the lessons learned on OPEN_1 to the design and construction
of OPEN_2, and in this way refine and accelerate the process
of constructing homes in the US. We believe that we are prototyping
the future of homebuilding.
The Open Building approach provides many advantages to the design/build
process for all the OPEN Prototype projects. These include:
Design for Flexibility
The systems and components in the OPEN Prototype have been designed to accommodate
changing uses and needs. This is particularly important for
the initial occupants of OPEN_1, some of whom are recovering from brain
injuries. As these occupants redevelop their physical and cognitive
abilities, the home will evolve with them.
With multi-use buildings such as OPEN_1 and OPEN_2, that serve both as residences and public buildings, the function of the building changes--sometimes very quickly. The ability to make larger scale modifications relatively easily, is important. Interior partition walls have been configured in a way that they can be “uninstalled” and
moved. The task of turning two bedrooms into one, or making a living room into a larger entertainment area, becomes a straightforward operation. The
de-mountable baseboard provides access to wiring chases in the walls, should
outlets or data ports need to be changed or added. The easily-removed
ceiling panels provide access to repair or modify plumbing, heating, and
Disentanglement of Systems
Open Building views the home as a collection of layered systems. The
layers we identify include the site, the structure,
the skin, the space plan, the services, and the “stuff” within
the home. Keeping these layers separate, and disentangled, allows us to create systems using materials appropriate to their
expected life spans. Access to the system, commensurate with the need for
future modification, is designed into the initial plan.
Like the plumbing and electrical systems, the HVAC (heating, ventilation,
and air conditioning) system is designed into specific spaces
that do not interfere with the building’s structure or skin. The backbone of
this system, which is not expected to change significantly over time, will
be built of long-lasting materials preinstalled in a central mechanical core
wall. The branches of this system are accessible
within the Open Built® ceiling system, allowing for service or modification, should the layout of the home be changed.
Delivering Prebuilt Systems to the Site
The Open Building principle of integrated systems is best expressed
in a production process that involves off-site fabrication of
finished components that are delivered to the site, and then assembled quickly and efficiently.
Prebuilding components in the controlled conditions of a production shop
makes sense for many reasons. Working conditions in a shop are more
predictable than on job sites subject to weather and seasons. The quality
of materials and workmanship can be assured. Computerized numerically-controlled (CNC) machinery can be incorporated. Jigs and fixtures can
dramatically improve production efficiency.
Bensonwood’s Open-Built® process was particularly advantageous
for the first OPEN Prototype, OPEN_1, built at the
Crotched Mountain Rehabilitation Center (CMRC). The brief construction
time on site — thirty working days — minimized the disturbance to CMRC’s
campus and to its inhabitants, some of whom are especially sensitive
to noise and dust.
Planning Inclusively and Building Virtually
Open Building maintains that everyone involved in the design
and construction of a building is in a position to contribute
to a successful outcome. By involving the major stakeholders and the
key subcontractors in the planning process, we are able to optimize
the performance, appearance, and value inherent in the OPEN Prototype projects. We are also
minimizing the potential for the conflicts that are
common on a typical construction site—conflicts about time, space,
and quality during the construction process.
The lead designers spend many hours meeting with the clients to ensure that the OPEN Prototype projects serve the intended
project steward team provides expertise in project management.
They coordinate meetings with the electrician, the
plumber, the HVAC subcontractor, and others, to discuss how and
when the systems will be installed. Much of this work has been
facilitated by sophisticated 3-D modeling software.
Designers create the architectural drawings that include site details and seasonal variables (topography, solar exposure, and shading). Engineers can feed their information--snow loads, wind variables, and weights that determine structural materials and sizing--into the modeling software. Wall panel and roof panel systems are planned and added to the design, along with interior and exterior finishes. The subsystems are designed and included in the process, with direct input from the individual subcontractors. Once the total design is complete, a virtual three dimensional model is visible.
This process produces a very high quality end result--timbers, panels, and subsystems in place and ready for on site assembly.