Construction Concerns: Parging

By Gregory Havel

Parging (or pargeting) is a way to apply a smooth surface to a masonry wall. It is most commonly used to apply a smooth surface to the exterior of a masonry foundation so that a waterproofing compound can be applied more easily.

Parging is also frequently used to cover up deteriorating masonry on the outsides of buildings or to provide a smooth surface for application of new finishes on the inside and outside of a building.

Photo 1 shows a wall of a building that has parging. The adjacent building was demolished, and its absence left this wall more exposed to the weather than its builders had intended. As in most older commercial buildings, the wall facing the street was finished with an attractive, more expensive brick, while the side walls—which were never intended to be seen—were finished with a less expensive and less attractive brick.

(1. Photos by author.)

 

Photo 2 shows parging that has been in place long enough that it has begun to deteriorate. It shows many cracks, and a part of the outer layer has fallen off.

(2)

 

Parging sometimes is used in new construction to give the new building an appearance of age. Photo 3 shows a wood-frame building with a stone veneer, part of which has parging so that it will appear older than it is.

(3)

 

Parging is usually mortar or Portland-cement based and is applied with a trowel, usually in several thin coats, directly over the masonry that it repairs or conceals.

Stucco can have a similar appearance or it may have a textured or decorative appearance. Stucco is Portland-cement based and is usually applied over expanded metal lath that is fastened to the sheathing of the building or to the masonry wall. It is usually applied in several layers, each of which is thicker than a layer of parging. Although it is considered an exterior building finish, stucco has also been used to conceal deteriorating masonry.

Unless there is a note on a preincident plan about the parts of a building that are finished with parging or stucco, for our own safety we should assume that these finishes conceal deteriorated or unstable masonry until we can prove otherwise.

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Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 30-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor's degree from St. Norbert College; has more than 30 years of experience in facilities management and building construction; and has presented classes at FDIC.

 


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