The ability of a material to accept within its body, quantities of gases or liquid, such as moisture
Tag: moisture
Birdbath
Random, inconsequential amounts of residual water on a roof membrane.
Boot
(1) a covering made of flexible material, which may be preformed to a particular shape, used to exclude dust, dirt, moisture, etc., from around a penetration; (2) a flexible material used to form a closure, sometimes installed at inside and outside corners.
Cementitious Waterproofing
Heavy cement-based compounds and various additives that are mixed and packaged for use in a dry form; the packaged mixture is then mixed with water and liquid bonding agents to a workable concrete-like consistency.
Centipoise
A unit of measure of absolute viscosity. (The viscosity of water is one centipoise. The lower the number, the less viscous the material.)
Centistoke
A unit of viscosity; the ratio of a liquid’s absolute viscosity to the density of that liquid.
Condensate
The liquid resulting from the condensation of a gas.
Condensation
The conversion of water vapor or other gas to liquid phase as the temperature drops; the act or process of condensing.
Condense
To make denser or more compact, as when a material (e.g., water vapor) changes from its gas phase to its liquid phase.
Counterflashing
Formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, rooftop unit or other surface, to cover and protect the upper edge of a base flashing and its associated fasteners.
Dew Point
The temperature at which air becomes saturated with water vapor. The temperature at which air has a relative humidity of 100%.
Diaphragm
A floor slab, metal wall panel, roof panel, or the like, having a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems.
Diffusion
The movement of water vapor from regions of high concentration (high water vapor pressure) toward regions of lower concentration.
Equilibrium Moisture Content (EMC)
(1) the moisture content of a material stabilized at a given temperature and relative humidity, expressed as percent moisture by weight.
Field Seam
A splice or seam made in the field (not factory) where overlapping sheets are joined together using an adhesive, splicing tape, or heat- or solvent-welding.
Flood Test
The procedure in which a controlled amount of water is temporarily retained over a horizontal surface to determine the effectiveness of the waterproofing system.
Humidity
The condition of the atmosphere with respect to water vapor. See relative humidity.
Hydrostatic Pressure Relief System
A system of perimeter and/or under slab drains used to regulate the hydrostatic pressure in the earth surrounding a below-grade structure.
Hygroscopic
Attracting, absorbing and retaining atmospheric moisture.
Ice Dam Protection Membrane
A continuous membrane installed under steep slope roofing materials in areas subject to ice damming that prohibits water which gets through the roof covering from getting into the structure. Must also seal the fasteners that penetrates it.
Metallic Waterproofing
Consist of finely graded iron particles combined with an oxidizing catalyst. When mixed with water (or water, cement, and sand), the finely distributed particles expand, creating a waterproof layer that becomes a part of the surface to which it is applied.
Mildew
A superficial growth produced on organic matter or living plants by fungi.
Moisture Contour Map
A map used to graphically define the location of moisture within a roof assembly after a moisture scan has been performed
Moisture Relief Vent
A venting device installed through the roofing membrane to relieve moisture vapor pressure from within the roofing system.
Moisture Scan
The use of a mechanical device (capacitance, infrared, or nuclear) to detect the presence of moisture within a roof assembly. (see Non-destructive testing.)
Positive Side Waterproofing
An application where the waterproofing systems and the source of the hydrostatic pressure are on the same side of the structural element.
Relative Humidity
The ratio of the pressure of water vapor present in a given volume of air to the pressure of fully saturated water vapor at the same temperature, expressed as a percentage.
Seam
A joint formed by mating two separate sections of material. Seams can be made or sealed in a variety of ways, including adhesive bonding, hot-air welding, solvent welding, using adhesive tape, sealant, etc.
Skirt Flashing
A formed metal counterflashing secured under a mechanical unit or skylight to cover and protect the upper edge of a base flashing and its associated fasteners
Vapor Migration
The movement of water vapor from a region of high vapor pressure to a region of lower vapor pressure.
Vapor Pressure
The pressure exerted by a vapor of a solid or liquid when in equilibrium with the liquid or solid.
Vapor Retarder
A layer(s) of material or a laminate used to appreciably reduce the flow of water vapor into a roof assembly.
Viscous
Resistant to flow under stress.
Water Stop
A diaphragm used across a joint as a sealant, usually to prevent the passage of water.
Water Table
The level within the ground, below which the soil is saturated with water.
Water Vapor Transmission
A measure of the rate of transmission of water vapor through a material under controlled laboratory conditions of temperature and humidity. Customary units are grains/h·ft2.
Water-Shedding
The ability of individual, overlapping components to resist the passage of water without hydrostatic pressure.
Waterproofing
Treatment of a surface or structure to prevent the passage of water under hydrostatic pressure.
Weatherproof
The ability of a membrane or roof covering to prevent the passage of water with a limited amount of hydrostatic pressure.
Wet
A condition where free water is present in a substance.
Wicking
The process of moisture movement by capillary action.