Glossary

Air Barrier by Joseph W. Lstiburek — last modified 2007/05/21

Air barriers are systems of materials designed and constructed to...

Air Retarder by Joseph W. Lstiburek — last modified 2007/05/21

Materials and assemblies that do not meet the performance requirements of...

Conditioned Space by ASHRAE Standard 62.2 — last modified 2007/05/21

The part of the building that is designed to be thermally conditioned for the...

Diffusion by Joe Lstiburek — last modified 2006/06/11

The movement of individual molecules through a material...

Drainage Plane by Joseph W. Lstiburek — last modified 2007/05/21

Drainage planes are water repellent materials (building paper...

Equivalent Leakage Area of a Building (EqLA or ELA) by Joe Lstiburek — last modified 2006/06/11

Quantitative expression of the airtightness of a building enclosure...

Foundation, Water-managed by Joe Lstiburek — last modified 2006/06/11

Systems for at or below-grade enclosure assemblies...

Grade Beam by Joe Lstiburek — last modified 2006/06/11

A foundation wall that is cast at or just below the grade...

Housewrap by Joe Lstiburek — last modified 2006/06/11

Any of the numerous spun-fiber polyolefin rolled sheet goods...

Indoor Air by ASHRAE Standard 62.2 — last modified 2007/05/21

Air in a conditioned space.

Insulating Sheathing by Joe Lstiburek — last modified 2006/06/11

Non-structural insulating board products with varying R-values...

Jump Duct by Joe Lstiburek — last modified 2006/06/11

A flexible, short, U-shaped duct...

Kiln-dried Lumber by Joe Lstiburek — last modified 2006/06/11

Any lumber placed in a heated chamber or "shed" to reduce its moisture content...

Low-E by Joe Lstiburek — last modified 2006/06/11

Most often used in reference to a coating for high-performance windows...

Mechanical Ventilation by Joe Lstiburek — last modified 2006/06/11

Controlled, purposeful introduction of outdoor air to the conditioned space.

Outdoor Air by ASHRAE Standard 62.2 — last modified 2007/05/21

Air outside the building.

Ozone by Joe Lstiburek — last modified 2006/06/11

This 3-atom molecule is an even more active oxidizing agent than its more common 2-atom relative . . .

Pressure Boundary by ASHRAE Standard 62.2 — last modified 2007/05/21

The primary air enclosure boundary separating conditioned air and unconditioned...

Thermal Boundary by Joe Lstiburek — last modified 2006/06/11

The layer in a building enclosure that controls the transfer of energy...

Vapor Barrier by Joseph W. Lstiburek — last modified 2007/05/23

A vapor barrier is a material that has a permeance of...

Vapor Impermeable by Joseph W. Lstiburek — last modified 2007/05/21

Materials with a permeance of 0.1 perm or less...

Vapor Permeable by Joseph W. Lstiburek — last modified 2007/05/21

Materials with a permeance of greater than 10 perms...

Vapor Retarder by Joseph W. Lstiburek — last modified 2007/05/21

A vapor retarder is a material that has a permeance of...

Vapor Semi-Impermeable by Joseph W. Lstiburek — last modified 2007/05/21

Materials with a permeance of 1.0 perm...

Vapor Semi-Permeable by Joseph W. Lstiburek — last modified 2007/05/21

Materials with a permeance of 10 perms...

Water Resistant Barrier by Joe Lstiburek — last modified 2006/06/11

A water resistant barrier (WRB) is also referred to as a drainage plane...

Wind-Washing by Joe Lstiburek — last modified 2006/06/11

The phenomenon of air movement that occurs due to wind...

Xeriscaping by Joe Lstiburek — last modified 2006/06/11

Climate-tuned landscaping that minimizes outdoor water use...

Zero Energy House by Joe Lstiburek — last modified 2006/06/11

Any house that averages out to net zero energy consumption...

Permeance by Joe Lstiburek — last modified 2006/06/11

The physical property that defines the ease at which water molecules...

R-value by Joe Lstiburek — last modified 2006/06/11

Quantitative measure of resistance to heat flow...

U-factor by Joe Lstiburek — last modified 2006/06/11

Quantitative measure of heat flow or conductivity...

Ventilation by John Straube — last modified 2006/06/11

The intentional flow of air into occupied spaces . . .

Wind Washing by John Straube — last modified 2006/06/11

The effect of wind-driven air movement through air permeable insulation reduces its insulating value . . .

Water Resistant Barrier by John Straube — last modified 2006/06/11

A sheet, spray- or trowel-applied membrane or material layer . . .

Sourced Drained by John Straube — last modified 2006/06/11

Another term for a face sealed system . . .

Sheathing Membrane by John Straube — last modified 2006/06/11

A generic term for a membrane layer that prevents the resists the passage of liquid water and possibly air and vapor . . .

Sealant by John Straube — last modified 2006/06/11

A flexible, polymer-based elastomeric material . . .

Semi-rigid Insulation by John Straube — last modified 2006/06/11

Board material which provides thermal resistance comprised of mineral fibers . . .

Rigid Insulation by John Straube — last modified 2006/06/11

Rigid board material which provides thermal resistance . . .

Radiation by John Straube — last modified 2006/06/11

A form of energy in electro-magnetic radiation . . .

Psychrometrics by John Straube — last modified 2006/06/11

The study of air and its energy and water vapour contents.

Joints by John Straube — last modified 2006/06/11

An interface between elements . . .

Flashing by John Straube — last modified 2006/06/11

A waterproof material used to redirect or shed drained water, or occasionally to act as a capillary break . . .

Expansion Joint by John Straube — last modified 2006/06/11

A structural separation between building elements . . .

Air Barrier; Performance Requirements by Joseph W. Lstiburek — last modified 2006/12/05

Air barrier systems typically are assembled from materials incorporated in . . .

Building Enclosure by Joseph W. Lstiburek — last modified 2007/05/22

A building enclosure is the component (typically comprised . . .

Mold by Joseph W. Lstiburek — last modified 2006/12/05

Mold is one type of fungus which is different from plants, animals and . . .

EIFS (external insulation finishing system) by Joseph W. Lstiburek — last modified 2006/12/05

A combination of insulation and stucco system cladding for . . .

Spectrally Selective Glazing by Joseph W. Lstiburek — last modified 2006/12/05

These types of window systems reduce solar gain while still providing daylighting . . .

Hygroscopic by Building Science Corporation — last modified 2006/12/05

Materials that change their permeability characteristics as relative humidity . . .

Hydrophobic by Joseph W. Lstiburek — last modified 2006/12/05

Materials that do not change their permeability as a function of relative . . .

Commissioning by Joseph W. Lstiburek — last modified 2006/12/05

Prior to occupancy, testing and inspections should note any problems and they . . .

Air Barrier System by Joseph W. Lstiburek — last modified 2007/05/22

An air barrier system is an assembly of materials that together . . .

Air-impermeable by Joeseph W. Lstiburek — last modified 2007/05/21

A material or assembly having an air permeance equal to or less than...

Occupiable Space by ASHRAE Standard 62.2 — last modified 2007/05/21

Any enclosed space inside the pressure boundary and ...

Habitable Space by ASHRAE Standard 62.2 — last modified 2007/05/21

Building space intended for continual human occupancy. Such space generally...

Vapor Control Layer (or Layers) by Joseph W. Lstiburek — last modified 2007/05/21

The element (or elements) that is (or are) designed and installed...

Vapor Permeance Classes by Joseph W. Lstiburek — last modified 2007/05/21

Test procedure for determining vapor permeance class is...

Subflorescence/Sub-efflorescence by John Straube — last modified 2007/06/05

A potentially harmful accumulation of water soluble salts that . . .