Namesort descending Definition

A building enclosure rain control strategy (or ground water control) that accepts that some water will penetrate the outer surface (the cladding, which “screens” rain) and removes this water back to the exterior by gravity drainage over a drainage plane, through a drainage gap, and exiting via flashing and weep holes. Many wall systems (lap siding, brick veneer) and sloped roof systems (metal, asphalt shingles) employ drained strategies.


An enclosure system that control rain penetration using the drained approach.

Drip Edge

A geometric feature provided in an exterior building surface to ensure that flowing water will drip free rather than be pulled back toward a vertical element due to surface tension or gravity. A drip groove is commonly employed in solid materials like concrete whereas a drip edge is used for thinner sheet materials.


Related resources: BSI-050: Parapets—Where Roofs Meet Walls; BSI-051: Decks—Roofs You Can Walk On


To develop the ultimate properties of a wet state material solely by evaporation of volatile ingredients.


A solid material's ability to change shape under tensile stress. For example, a piece of metal exhibits ductility when it is drawn into a wire.


The capability of a building, assembly, component, or product to maintain serviceability over a specified time.


abbr. electronically commutated motor

See Brushless Permanent Magnet (BPM).


abbr. Eastern Dakota Housing Alliance

The Eastern Dakota Housing Alliance was formed in 1996 as a loose affiliation of non-profit organizations interested in increasing the availability of affordable housing in their communities.


abbr. Energy and Environmental Building Association

EEBA's mission is to provide education and resources to transform the residential design, development and construction industries to profitably deliver energy efficient and environmentally responsible buildings and communities.


abbr. energy-efficient mortgage


abbr. energy efficiency rating


abbr. energy factor

A water heating efficiency metric.


The deposition of dissolved salts in the material (such as concrete or brick) being transported within water (usually by capillary action) on a visible surface after evaporation of the water.


abbr. Environments for Living®

The Environments For Living® program is an initiative of Masco Home Services, Inc., a Masco company. The program was launched in 2001, in response to a growing need for professional services to support regional and national home builders in applying building science and energy-efficient construction practices in the field.


abbr. Energy Gauge USA

The residential front-end user interface developed by the Florida Solar Energy Center (FSEC) for the DOE2.1E simulation tool.


abbr. external insulation finishing system

A system which combines exterior insulation and some type of stucco cladding for buildings. Based on rain control strategy, there are two types of EIFS available in the U.S.—perfect barrier face-sealed systems and drained systems.

Electronically Commutated Motor

See Brushless Permanent Magnet (BPM).


A drawing or rendering of a face of a building.


To encapsulate the EIFS reinforcing mesh in the base coat.


Brand name for a pre-formed compressible foam joint filling product used to provide a seal between building components.

End Dam

A vertical or near vertical upstand from the end of a flashing or window sill, used to prevent water from flowing horizontally off the end of the flashing or sill.

End Wrapping

In EIFS, the act of wrapping the reinforcement and base coat around the edges of the insulation board and terminating and bonding to the substrate at an opening in the substrate. Like back wrapping, end wrapping is a means of securely fixing the lamina where it ends at joints and penetrations.


In a general sense, the capacity to do work; typically stated in units of Joules (SI) or Btu (Imperial).


A joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy. The ENERGY STAR label is used to identify and promote more energy-efficient products, including houses and other buildings.

Energy Truss

See Raised Heel Truss.


Thermodynamic quantity equal to the sum of the internal energy of a system plus the product of the pressure-volume work done on the system. Enthalpy cannot be directly measured; however, enthalpy differences between the initial and the final state points of a process can be measured (from Gatley, Understanding Psychrometrics).


abbr. U.S. Environmental Protection Agency

The EPA develops and enforces regulations, gives grans, studies environmental issues, sponsors partnerships, teaches people about the environment, and publishes information.



abbr. expanded polystyrene insulation

See Expanded Polystyrene Insulation.

Equivalent Leakage Area of a Building

A quantitative expression of the airtightness of a building enclosure. EqLA is the method set by the Canadian General Standards Board in which a blower door depressurizes the building enclosure to 10 Pascals and the leakiness of the enclosure is expressed as a summary hole in square inches. ELA is set by the ASTM equivalent procedure at a pressure differential of 4 Pascals.


abbr. Energy Recovery Ventilator or Enthalpy Recovery Ventilator

Expanded Polystyrene Insulation

 A rigid cellular foamed plastic insulation material manufactured by expansion of polystyrene beads within a mold. This mold creates an open cell structure filled with air. EPS Type I is the most widely used insulation. Type I has a density of 1 lb/ft3 (16 kg/m3) ), Type II is a denser, more durable insulation of 1.5 lb/ft3  (24 kg/m3) density.

Expansion Joint

A structural separation between building elements that allows independent movement without damage to the assembly.

External Insulation Finishing System

A system which combines exterior insulation and some type of stucco cladding for buildings. Based on rain control strategy, there are two types of EIFS available in the U.S.—perfect barrier face-sealed systems and drained systems.

Variants: EIFS

Extruded Polystyrene Insulation

A rigid cellular foamed-plastic insulation material manufactured by extrusion of polystyrene in the presence of a blowing agent. The blowing agent creates a porous structure that resists liquid water penetration and vapor diffusion. The manufacturing process for XPS insulation results in a smooth surface skin. Typical density of 2 lb/ft3 and R-value of 5 per inch (0.029 W/mK).

Variants: XPS


A visible exterior face of a building.


A building enclosure rain control strategy that relies on the exterior face of the enclosure to act as a perfect barrier to rain penetration. This method typically relies on exposed sealants to provide rain tight joints, and hence is highly reliant on workmanship and maintenance to achieve performance. Failure is defined as water penetration of the face. It is a sub-set of perfect barrier rain control strategies.

Related Terms: Concealed Barrier, Drained



A mechanical space conditioning device comprising an enclosure, a fan to move air, and a finned extended surface heat exchanger (a “coil”). The coil transfers heat from refrigerant (“DX” or “direct expansion”), water or fluid to the air stream to heat or cool the air passing through. In many cases, a fancoil might also contain a filter and duct connection flanges. Can be installed as an exposed device or hidden in floors or ceilings.


A general term describing any of a variety of screws, nails, rivets, etc. that are used for mechanically securing various components of a building.


abbr. fancoil unit

See Fancoil.


A glazed opening in a building enclosure, for example a window, door, vent, or skylight.