Some of the terms used in damp proofing are explained below.
Sweating: The process by which humidity from the air will condense upon any surface below dewpoint temperature such as window-panes or walls.
Condensation: The transformation of vapour into liquid because the temperature drops below a given level, specific to each liquid.
Surface Condensation: The condensation of liquid on cold glass or when damp air comes into contact with surfaces below the dewpoint, i.e. the temperature at which the air becomes saturated.
Damp Course: A horizontal layer of a watertight material, such as dense limestone or metal, laid upon the lower course of a masonry wall to prevent damp ascending through the brickwork by capillary action. Also called damp check or damp proof course.
Vapour Retarder: A membrane covering the outside of the insulation around a cold water pipe to prevent the damp from soaking the insulation and reaching the pipe. Also called vapour barrier.
Pargeting: A thin layer of mortar with added dampproofing ingredients applied on the outside of masonry walls of basements, near the foundations, below grade. Also called pargework or parging.
Roofing Felt: A waterproofing material consisting in asphalt saturated felt sheet, dressed with another more resistant layer of asphalt with mineral fibers or organic stabilizers; the side exposed may bre coated with aluminum sheet or other solar protection. Also called as asphalt prepared roofing.
Protected membrane roof: A waterproof membrane that also provides insulation from extreme temperatures by means of a rigid insulation board coated by a layer of gravel.
Compression Gasket: A strip molding of extruded synthetic rubber designed to be fixed to a window – frame; firmly compressed by the pane of glass, to create a waterproof seal.
Joint Sealant: Material designed to fill the joints in a building so as to create, when dry or curved , a flexible weatherproofing seal.
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