Distance between joints should be no more than 5.5 m (18 ft)in any direction.Each continuous vertical area should be no more than 13.4 m2.Dryingshrinkage cracks are often caused by violating the rules ofcontrol joint spacing (ASTM C 1063): Common causes of cracking are improperly placed control joints, improper lathinstallation, and inadequate curing.Ĭontrol joints are provided in plaster to relieve drying shrinkagestresses and to provide stress relief in areas subjected tomovement, such as window and door openings. Water that getsbehind the plaster can cause woodlath to rot and metal lath and nailsto rust, and can cause plaster todelaminate from the substrate.Ĭracking in plaster is usuallyshrinkage-related or the result ofexternal loads, such as groundsettlement or inadequate stiffness of the backing. In manycases, damage results from waterinfiltration into the buildingstructure either through cracks,through the roof, aroundchimneys, or through window anddoor openings. Repair of Portland Cement Plaster (Stucco)Ĭauses of PlasterDamagePortland cement plaster can deteri-orate for a variety of reasons,including inadequate designdetails, poor installation, or the useof improper materials. Portland cement plaster is often applied to metal lath attached to frame construction. Integrating patches into the existing plaster is oneof the many challenges of plaster repair. © 2001 Portland Cement Association IS526All rights reserved Thispublication does not address synthetic plaster(EIFS) systems. Thismanual presents recommended procedures forrepairing portland cement plaster. Hard, durable cladding, it is not intended toresist building movements, such as those fromsettlement or the expansion of wood framemembers as a result of moisture intrusion. Plaster has proved to be a durable wall covering in allclimates and has great appeal as a surface finish because of itsutility, low first cost, and need for minimal maintenance.īut like all building materials, plaster deteriorates with age andexposure to the elements. Portland cement plaster has many qualities that make it a desirablefacing material, including hardness, fire resistance, and attractiveappearance. The first coat is oftenreferred to as the scratch coat, the second is the brown coat, andthe third is the finish coat (Fig. When applied to metal lath, three coats of plasterform a 22-mm (7/8-in.) total thickness. It may be applied directly to a solid base, such asmasonry or concrete walls, or it can be applied to metal lathattached to frame construction, masonry, or concrete construction.Īpplied directly to concrete or masonry, plaster provides atough, 13-mm (1/2-in.) thick facing that is integrally bonded tothe substrate. Plaster is applied either byhand or machine to exterior and interior wall surfaces in two orthree coats. Portland cement plaster (stucco) is a building facing materialconsisting of portland cement-based materials and sand, mixedwith water to form a workable mixture. Repair of Portland Cement Plaster (Stucco) © 2001 Portland Cement Association IS526 All rights reserved Integrating patches into the existing plaster is one of the many challenges of plaster repair. This publication does not address synthetic plaster (EIFS) systems.
#Repair of portland cement plaster stucco manual#
This manual presents recommended procedures for repairing portland cement plaster. Although cement plaster provides a hard, durable cladding, it is not intended to resist building movements, such as those from settlement or the expansion of wood frame members as a result of moisture intrusion. But like all building materials, plaster deteriorates with age and exposure to the elements. Plaster has proved to be a durable wall covering in all climates and has great appeal as a surface finish because of its utility, low first cost, and need for minimal maintenance. Portland cement plaster has many qualities that make it a desirable facing material, including hardness, fire resistance, and attractive appearance. The first coat is often referred to as the scratch coat, the second is the brown coat, and the third is the finish coat (Fig. When applied to metal lath, three coats of plaster form a 22-mm (7/8-in.) total thickness. Applied directly to concrete or masonry, plaster provides a tough, 13-mm (1/2-in.) thick facing that is integrally bonded to the substrate. It may be applied directly to a solid base, such as masonry or concrete walls, or it can be applied to metal lath attached to frame construction, masonry, or concrete construction. Plaster is applied either by hand or machine to exterior and interior wall surfaces in two or three coats. Portland cement plaster (stucco) is a building facing material consisting of portland cement-based materials and sand, mixed with water to form a workable mixture.
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