DK Ching VD - Moisture Protection

moisture protection

restricting by various means the passage or migration of water or water vapor through a building assembly or construction

vapor retarder

a material of low permeance, as plastic film or foil, installed in a construction to retard the transmission of moisture from the interior environment to a point where it can condense into water; also called "vapor barrier"

dampproofing

the treatment of a masonry or concrete surface to retard the absorption of water or penetration of water vapor, either by applying a waterproof coating or by using a suitable admixture

parging

a thin coat of cement mortar for smoothing the surface of rough masonry or for sealing a masonry wall against moisture

waterproofing

a membrane or coating applied to render a surface impervious to water

asphalt mastic

a mixture of asphalt, graded mineral aggregate, and fine mineral matter than can be poured when heated and hardens when exposed to air, used as an adhesive, as a joint sealant, and in waterproofing

mastic

any of various pasty preparations containing bituminous materials and used as an adhesive or sealant

gravel drain

a layer or fill of crushed rock or gravel placed to ensure adequate drainage of groundwater while preventing the entry and flow of sediment and silt

drainage mat

a two-part material for draining groundwater, such as from behind a foundation or retaining wall, consisting of synthetic matting or an eggcrate core, faced on one or both sides with a filter fabric

filter fabric

a geotextile fabric that allows water to pass freely into an underground drainage medium but prevents fine soil particles from entering and clogging the system

geotextile

any of a class of synthetic fabrics used to separate soil materials, filter fine soil particles from drainage medium, or control soil erosion

foundation drain

open-jointed tile or perforated pipe laid around the foundation of a building for the collection and conveyance of groundwater to a point of disposal

flashing

pieces of sheet metal or other thin, impervious material installed to prevent the passage of water into a structure from an angle or joint

through-wall flashing

flashing that extends from one side of a wall to the other

feint

a slight bend in the edge of a flashing forming a capillary break

pressure-equalized design

wall construction employing a rainscreen to eliminate any difference in air pressure between the exterior and the interior that would cause rainwater to move through joints in the wall

rainscreen principle

a concept for preventing the penetration of wind-driven rain through a wall, utilizing a rainscreen backed by a confined air space to shield an inner barrier where the primary air and vapor seals are located

rainscreen

an exposed outer layer of a wall, having openings designed to deter the penetration of rainwater and to equalize the air pressures on opposite sides of the facing

surface tension

the elastic-like force existing in the free surface of a liquid

capillary action

a manifestation of surface tension by which the greater adhesion of a liquid to a solid surface than internal cohesion of the liquid itself causes the liquid to be elevated against a vertical surface

wick

to draw off liquid by capillary action

capillary break

a space between two solid surfaces made wide enough to prevent the capillary action of moisture through the space

damp course

a horizontal layer of impervious material laid in a masonry wall to prevent the capillary rise of moisture from the ground or a lower course

cap receiver

a metal strip interlocking with and securing a cap flashing

cap flashing

flashing turned down to protect base flashing and prevent water from entering the joint; also called "counterflashing"

base flashing

flashing covering and protecting the joint between a roof and the vertical surface of a wall, parapet, or chimney

parapet skirting

roofing felt turned up against a parapet wall

cant strip

an inclined or beveled strip changing the pitch of a roof slope or rounding out the angle between a flat roof and a parapet [A]

tag

a strip of sheet metal folded over and used as a wedge to secure flashing in a masonry joint

lead wedge

a tapered piece of lead for securing flashing in a reglet

reglet

a groove cut or formed in a vertical surface to receive flashing

step flashing

flashing covering and protecting the intersection of a wall and the sloping part of a roof, consisting of L-shaped pieces that step down to follow the slope of the roof

passing

the distance by which one sheet of flashing overlaps another

filleting

material, such as mortar, used as a substitute for flashing where a sloping roof meets a wall

collar

a metal flashing for a vent pipe projecting above a roof deck

roof flange

a flange that fits around and provides a raintight seal for a ven pipe penetrating a roof deck

joint sealant

any of various viscous substances injected into a building joint, curing to form a flexible material that adhered to the surrounding surfaces and seals the joint against the passage of air and water

joint movement

the change in width of a building joint resulting from a change in temperature

extensibility

the capacity of a sealant to be extended in tension

high-range sealant

a joint sealant of polysulfide, polyurethane, or silicone capable of elongations up to 25%, used for sealing joints in curtain-wall systems

medium-range sealant

a joint sealant of butyl rubber or acrylic capable of elongations up to 10%, used for sealing nonworking or mechanically fastened joints

caulk

a low-range joint sealant used for filling or closing a seam, crevice or crack in order to make it watertight and airtight

bead

a narrow deposit of sealant applied to a building joint

bond face

the surface of a building component or joint that serves as a substrate for sealant and to which the sealant is bonded

substrate

any material that underlies and serves as a base or foundation

primer

a liquid for improving the adhesion of a sealant to a substrate

joint filler

a compressible strip, rod, or tube of resilient material, such as neoprene or butyl, used for filling a joint and controlling the depth of a sealant; also called "backup rod"

bond breaker

any of various materials, such as polyethylene tape, used for preventing the adhesion of a sealant to the bottom of a joint

construction joint

a joint between two successive placements of concrete, often keyed or doweled to provide lateral stability across the joint

dowel

a short reinforcing bar extending equally into two abutting sections of concrete to prevent differential movement

expansion sleeve

a pipe sleeve that allows the housed element to move freely in a longitudinal direction

waterstop

a flexible strip of rubber or plastic inserted across a concrete or masonry joint to prevent the passage of water

expansion joint

a joint between two sections of a building or structure permitting thermal or moisture expansion to occur without damage to either part

expansion joint cover

a prefabricated cover for protecting an expansion joint while allowing relative movement between the two parts being connected

control joint

a continuous groove or separation formed, sawed, or tooled in a concrete or masonry structure to form a plane of weakness and thus regulate the location and amount of cracking resulting from drying shrinkage or thermal stresses

contraction joint

a joint between two parts of a structure, designed to compensate for the contraction of either part

isolation joint

a joint separating two sections of a structure so that differential movement or settlement can occur between the parts