building a stucco wall. for centuries, stucco has proven to be one of the most enduring, versatile and weather-resistant exterior wall finishes available…and with its variety of colors and textures, stucco continues to be one of the most popular wall systems. stucco can be applied over standard, wood frame walls in a three-coat process and over masonry and poured concrete walls in a two-coat application. before starting your project, check local building codes for wall assembly and moisture barrier
requirements in your area. weather-resistant stucco walls require the use of two layers of grade d waterproof building paper over the wall sheeting including plywood, osb, exterior gypsum board and concrete board, before the application of the base coat stucco. when attaching the waterproof building paper, vertical seams should be overlapped by 6 inches or more and horizontal seams should be overlap pedby 4 inches, in shingle fashion. the building paper should also extend 16 inches
around all corners. once the water resistant building paper is in place, all trim accessories should be installed. trim accessories can be cut to size using metal snips. cut edges are often very sharp, so always wear gloves when working with these materials. a weep screed is a typical excess will be required by code. weep screeds are installed along the bottom edges to allow any water that has entered the wall to escape. casing beads should be installed to neatly terminate stucco at the end of the wall.
casing beads also act as a guide to help maintain a consistent stucco thickness. casing beads, for a three coats system,should be three quarters of an inch thick. casing beads for use in a two-coat system over masonry or concrete should be 1/2 inch thick. then, galvanized expanded metal lath or 1 inch woven wire stucco netting is installed over the entire surface,overlapping by one inch on the horizontal seams and two inches on the vertical seams.galvanized nails or staples should be
used every six inches, both vertically and horizontally. make sure that the nails or staples penetrate the studs a minimum of one inch. the lath or stucco netting should also extend 16 inches around all corners. if the base coat stucco is applied to a clean unpainted concrete or masonry surface,waterproof building paper and metal lath are not required. then, control joints should be placed to create wall panels no larger than 144 square feet,
keeping the panels as square as possible.stucco will shrink as it hardens and cures. control joints help reduce the potential for shrinkage cracking. expansion joints are required anywhere there are existing wall expansion joints and at inside corners and changes insubstrate. expansion joints are designed to allow for the expansion and contraction of the stucco wall panels with changes in temperature. corner trimshould be used on all outside edges, to protect the exposed stucco and to provide clean finished lines. now that the substrate isproperly prepared,
it is ready for the base coat stucco application. quik rete base coat stucco and quikr ete base coat stucco with water-stop are recommended for use in a traditional three coats system over wood sheeting and as the base for a two coat application over masonry or concrete. these pre-blended stuccos are extremely workable for hand applied stucco applications and have the high bond strength required for a successful project. mix the base coat stucco to a workable consistency. the proper consistency is achieved when the stucco will hang on a trowel
held at a 90 degree angle. stucco thatis mixed too wet will sag. stucco that is mixed too dry will not adhere properly to the metal lath. one bag of 80 pound base coat stuccowill cover about twenty seven square feet at three-eighths of an inch thick. using asquare trowel, held at a 45 degree angle, apply the basecoat stucco using firm trowel pressure to force the stucco into the lath. work from the bottom of the wall up andapply at a thickness of about three-eighths of an inch over the entire area. then,
using a straight edge or darby, screed the stucco to a uniform depth of 3/8 of an inch thick. once the stucco has become thumb print hard,scratch horizontal grooves, 1/8 of an inch deep, into the base coat, across the entirearea with a raking tool. this is why this step is commonly referred to as the scratch coat. allow the scratch coat to cure for 24 to48 hours. keep the surface of the stucco damp with a fine water mist. this step will help reduce shrinkagecracking, especially in hot dry
conditions. now, mix and apply another 3/8 inch layer of base coat stucco directly to the scratch coat. this step is called the brown coat. usinga straight board or darby, screed the brown coat surface to a true even 3/8 inch thickness. fill any surface boards witha dditional base coat. the total combined base coat depth should be three-quarters of an inch thick. as soon as the strucco has lost its sheen, float the surface uniformly. then, cure the base coat with a fine water mist for 24 to 48 hours.
for two-coat applications over masonry block walls and poured concrete walls, the scratch coat step is eliminated fromthe process. simply dampen the wall. apply the browncoat. then, screed and float the surface to a uniform 3/8 inch thickness. now that the base coat is complete, quikr ete finish coat stucco can be usedto provide numerous decorative color and texture options for your stucco wall. finish coat stucco is available in bothwhite and gray formulations and can be combined with more than 20standard quikrete stucco & mortar colors.
popular textures, such as heavy lace, light lace, dash, sand float and smooth finishes are easy to achieve with a little practice. working from the bottom of the wall tothe top, apply a consistent 1/8 inch thick coating of finish coatstucco. then, use a whisk brush to lightly dashfinish coat stucco onto the wall. then, use a trowel to knock down and flatten the stucco. if you prefer a heavier texture, firsts pread the finish coat stucco in a thin application to achieve good colorcoverage, and then, double back with a heavieruneven application.
once the heavy coat begins to hardenknock the finish down with a trowel, creating a heavy lace finish. if asmooth finish is your preference, simply use a trowel or sponge float in acircular motion. it is important to complete the entirewall in one application. this will help limit any colorinconsistencies from batch to batch. then, keep the surface damp for severaldays by applying a fine water mist.