- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 31 Jan 2017
Principles of enclosure
‘Enclosure’ is the term given to any part of a building that physically separates the external from the interior environment. It is often referred to as the ‘building envelope’, although ‘enclosure’ is considered the more precise term.
Human physiology is capable of tolerating only a narrow range of environmental conditions. Beyond this range, health and wellbeing are compromised. Through the materialisation of volumes, architecture is able to create enclosed spaces in the form of structures. A building consists of a collection of spaces bounded by separators of the interior environment, and separators of the exterior environment (the enclosure).
The physical components of the building enclosure include:
- The roof system.
- The above-grade wall system (including windows and doors).
- The below-grade wall system.
- The base floor system.
The principles of building enclosure were defined by the building scientist Neil Hucheon in 1963:
- Strength and rigidity.
- Control of heat flow.
- Control of air flow.
- Control of water vapour flow.
- Control of liquid water movement.
- Stability and durability of materials.
- Aesthetic considerations.
In addition to Hutcheon’s principles, there are also considerations relating to the natural phenomena occurring in the external world, and the functions required. Some of the environmental phenomena, or ‘loadings’, that can impact on enclosure include:
- Gravity (i.e. structural loads).
- Climate and weather.
- Seismic forces.
- Noise and vibration.
- Soil type.
- Organic agents (i.e. aerobic life forms such as insects and mould).
- Inorganic agents (i.e. natural and artificial substances such as radon and methane).
The general functions of the building enclosure may be divided into four areas:
- Support: To support, resist and transfer all structural forms of loading imposed by the interior and exterior environments.
- Control: To control, air transfer, heat, sound, access and security, privacy, the provision of views and daylight, and so on.
- Finish: To finish the enclosure surfaces in terms of visual, aesthetic, durability, and so on.
- Distribute: To distribute services or utilities such as electricity, communications, water, and so on.
Generally, enclosures are either monolithic or composite assemblies. Monolithic enclosures involve a single material acting as the structure, the cladding and interior finish, such as load-bearing masonry. In composite assemblies, separate materials or combinations are assigned critical control functions, such as control of heat transfer or air leakage.
In general terms, enclosure types include can be categorised as the following:
- Compact or distributed.
- High rise or low rise.
- Permeable or impermeable.
- Transparent or opaque.
- Passive or active.
- Massive or lightweight.
- Temporary or permanent.
- Single or multiple units.
- Hybrids: Combinations of the above.
 Related articles on Designing Buildings Wiki
- Building design.
- Building pathology.
- Building technology.
- Concept architectural design.
- Fabric structures.
- Structure definition.
- The building as climate modifier.
- The development of structural membranes.
- The history of fabric structures.
 External resources
Featured articles and news
Part of Designing Buildings Wiki, BREEAM Wiki will advance knowledge sharing for the BRE family of sustainability tools.
From the decorative to the utilitarian, and from the photographed to the forgotten.
New BRE book considers the progression from project-based knowledge creation to whole-life urban knowledge management.
This CIOB article explores the concept of value in building design and construction.
BREEAM and Measurabl announce integration to improve the financial performance of commercial real estate.
Rogers Stirk Harbour + Partners' release new images of soon-to-open 3WTC tower in New York.
A document can be called a bond or a guarantee. Does the name matter and what is the difference between them?
New briefing note is launched focusing on increasing knowledge of housing that promotes health and wellbeing.
Arbitration is a private, contractual form of dispute resolution used in the construction industry.
The European Parliament has approved a revised Energy Performance of Buildings directive.
One in six MPs supports the ring-fencing of retentions as proposed in the 'Aldous Bill'.
A stakeholder is anyone who has an interest in the process or outcome of a construction project.