A parge coat is a thin coat of a

cementitious A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

ic mortar applied to concrete or masonry for refinement of the surface.

Pargeting Pargeting (or sometimes pargetting) is a decorative or waterproofing plastering applied to building walls. The term, if not the practice, is particularly associated with the English counties of Suffolk and Essex. In the neighbouring county of Nor ...

is a more involved process, involving designs in relief created in the surface. Parging is usually applied with a trowel and pressed into the existing surface. The intent is to create a contiguous surface by filling imperfections such as surface air voids created by

bughole A bughole (or pinhole) is a small hole in the surface of a concrete structure caused by the expansion and eventual outgassing Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas t ...

-induced

outgassing Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which a ...

, to level a surface for aesthetic reasons, or to prepare a surface for topcoating with an additional form of protective

coating A coating is a covering that is applied to the surface of an object, usually referred to as the Substrate (materials science), substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquid ...

. Parging is a low-cost alternative to

repointing Repointing is the process of renewing the pointing, which is the external part of mortar joints, in masonry construction. Over time, weathering and decay cause voids in the joints between masonry units, usually in bricks, allowing the undesirable e ...

, providing structural cohesiveness to masonry walls whose mortar has begun to fail. Parge coating can also be used to create air tightness for apartments.

See also