Building Enclosures, Building Envelopes, And Facade Engineering

What Is Building Envelope?

A building envelope is the imaginary separation between a conditioned (or semi-conditioned) space and an unconditioned space. This includes certain walls, doors, windows, roofs and floors. Conditioned space are made comfortable for occupants by means of heating, ventilation, and air conditioning (HVAC). Unconditioned spaces include the outdoors and any space within a building not served by HVAC. The building envelope is indicated with respective temperature, humidity, and air speed differentials, which in turn allow to establish its requirements (e.g. condensation resistance, permeability and location of layers, etc.). This separation should typically be addressed by a thermally insulative layer controlling the heat flow, and in majority of cases it should control the air flow by use of e.g. air barrier.

What Is Building Enclosure?

A building enclosure can be easily defined as everything visible from the exterior plus everything made visible if the adjacent soil and rock were removed. The term Building Enclosure is synonymous with the term Facade, and includes but is not limited to: exterior walls, curtain walls, sloped glazing, skylights, doors, windows, louvers, screens, roofs, parapets, copings, cornices, ceilings, and floors. It is the physical protection of the interior against exterior adversary forces, such as elements, wildlife, wind, thieves, terrorists, etc. The main difference from the building envelope is the inclusion of those components that do not separate conditioned spaces from the unconditioned spaces. These components typically form a screening cladding, such as walls, roofs, and soffits of unconditioned spaces, as well as roofs above unconditioned attics, and shells of unconditioned garages and basements.

Building Enclosure Consulting

Building envelope (or enclosure) consultants work with parties of construction process and owners of the existing buildings helping them to define, achieve, or verify the tangible performance objectives (e.g. weatherproofing integrity) of those assemblies. The profession is not regulated and there is currently neither education nor benchmarking offered in the U.S. Universities in some countries (e.g. Bath in England) have established courses in Facade Engineering. Facade Engineering is the term used outside the U.S. and typically emphasize the structural engineering over other aspects of facade functionality. It's often used with reference to curtain walls, because modern facades are typically comprised of curtain walls as opposed to load-bearing walls. Therefore, similar descriptions would include Curtain Wall Consultant, Curtain Wall Expert, Curtain Wall Engineer, and CurtainWall Designer.
Building Enclosure Consulting is typically devoted to high-rise and high-end construction; one reason is the economical justification of the service, the other the scarcity of architects familiar with high-rise construction. Building Enclosure Consulting should comprise all functions of the building shell holistically. The elementary function is to protect the occupants by controlling forces acting on building enclosures such as: rain, wind, snow, hail, flood, sun, light, wind borne debris, blast, heat flow, water vapor, wildlife, aggressive airborne and waterborne chemical, noise, vibrations, fire, smoke, theft, dirt accumulation, maintenance loads, and normal wear and tear.
The consultants in the U.S. come from miscellaneous walks of life and therefore rely mainly on their individual experience. They typically specialize in the specific phase (e.g. material research, design, delegated design, construction, architectural rehab, forensic investigations) as well as in specific functionality aspects (e.g. resistance to heat, air, moisture, noise, fire, smoke, etc.) and specific systems (e.g. thermoplastic roofing, ceramic cladding, curtain walls, etc.) The industry is highly fragmented, with a number of consultants working in small firms. They typically compete with middle, large, and jumbo -sized multidisciplinary engineering firms offering building enclosure consulting services in addition to their core activities.

Benefits of Employing a Building Enclosure Consultant

The functionality of building enclosures is as crucial to the cost of construction and maintenance as it is missing in mainstream architectural and engineering curricula. Lacking a knowledgeable party during design, construction, and investigations of facades is risky, and was proven many times to lead to substantial short and long-term losses for building owners. This challenge is well illustrated by the famous saying "If the roof doesnt leak, the architect hasnt been creative enough"credited to the famous architect Frank Lloyd Wright. Some jurisdiction recognized this weakness, and consequently refused to issue building permits unless their documentation had been reviewed by a building enclosure professional. Other jurisdiction (e.g. New York City and Chicago), as a result of causalities among pedestrians, require facades of high-rise buildings to be periodically reviewed. Therefore, working with a building enclosure/envelope consultants typically confers a financial benefit very substantially exceeding their professional fees.