Texturedskip trowel knock down is a same day two coat application with a float finish background. Aug 08, 1986 the first coat, called the scratch coat, is troweled over the wire mesh to completely embed it. The most traditional and popular of these types is 3 coat stucco, in which stucco is applied in three coats over metal reinforcement. You can use a depth gauge to help determine that you are within that depth. I am currently in the process of stucco ing my house. Certain fine or smooth textures accentuate cracks in stucco, while heavier textures tend to hide stucco cracks. I see a lot of cracks on the foam trim that is used on stucco houses quite often and. This article will give you some helpful advice on how to properly mix stucco.
Finish coat stucco a blended, decorative, water resistant, portland lime cement based, finishcoat stucco for use as a decorative finish coat for vertical and overhead application. Carry the stucco to the work on a square of plywood or sheet metal, then scoop it directly onto the. Stucco guru, scratch, brown and color with a skip trowel finish hi guys, this video explains how to repair windows. Mar 03, 2016 now that you know why stucco cracks, lets find out how serious a stucco crack can be. How to repair a hole in a stucco wall, car ran into. Below are some examples of some hairline cracks that have occurred. Patching of hairline cracks is not recommended as it will detract from the natural beauty of the stucco and will serve no useful purpose. The brown coat adds strength and acts as a base for the finish coat, which can be handtroweled to create a custom surface texture.
This is a traditional three coat stucco installation not acrylic over selffurring wire mesh 2x2 wire spacing. Scratch coats are particularly important in the world of vertical decorative concrete. You can use a hock and trowel to lay it on spraying it on will also work and try to maintain a 38. As a building material, stucco is a durable, attractive, and weatherresistant wall covering. Application of the brown coat before the scratch coat has properly cured, and failure to make the additional trowel. It was traditionally used as both an interior and exterior finish applied in one or two thin layers directly over a solid masonry, brick, or stone surface. Scratch coat over concrete, masonry, cement backer board or metal lath. Oct 23, 20 often, when wallpaper was being applied to a rooms plaster, the brown coat was the final coat, as there was no reason for the finish coat. Ustucco xpx may also be used over wood or gypsum backing and as a scratch and brown coat application for traditional stucco systems.
Applying the stucco first or scratch coat the first, or scratch, coat, which forms the base for the next two coats, should completely encase the reinforcement. Scratch stucco plastering kirk giordano plastering. Instead, wet the area and apply dry cement to the crack. I would really appreciate if you can share your expertise and let. The finish coat may be either portland cement plaster or acrylic, typically 18. It is integrally colored with faderesistant pigments, and is economical with low maintenance. The scratch coat consists of a layer of plaster that is grooved while wet. One coat fibered stucco factory blended mixture of portland cement, sand and fiber reinforced polymers and packaged in moisture resistant bags. Once moisture or water gets inside a wall, it will inevitably cause further damage. Apply stucco scratch coat, bbb plastering contractors, plaster walls, plastering jobs, scratch, stucco guru, stucco scratch coat. Often, when wallpaper was being applied to a rooms plaster, the brown coat was the final coat, as there was no reason for the finish coat.
Attach wood guide strips vertically to the surface with mortar ribbons to provide a gauge for the finish coat. Crack fixing on smooth hard trowel finish stucco youtube. I used the mesh to scratch with, and used several different mason trowels and a pointing trowel to get in the crevices and scoop the slop out. These hairline cracks in no way compromise the integrity of the plaster coat nor shorten the useful life of the product. This patch is designed to repair the thin layer max 316 of. The scratch can be applied with a hawk and trowel, or sprayed on. Complies with astm c 926 requirements for cement based plaster. The only scratch i left was about 6 or 8 around the perimeter of the stones that were installed and scratched. The most traditional and popular of these types is 3coat stucco, in which stucco is applied in three coats over metal reinforcement.
Although not all cracks are objectionable, cracks in stucco acceptable to one person might be unacceptable to another person. Hairline cracks are typically around a 116 of an inch wide or smaller, if the crack is bigger than that, than chances are that some other element is the culprit. Instead of using a scratcher, an instrument called a darby is used instead. Scratch coats can be applied by hand, trowel, or sprayer. As you go along, trowel the patch so that it matches the surrounding stucco finish. Is awaiting application of the brown coat and finish coat. After my contractor applied the brown coat its been over a week now i see a lot of hair line cracks and lines on one of the walls.
Apply the mud from top down in strips using the flat trowel, being sure to force the mud into the gaps in the lath. This flexing creates a deflection of the material and leads to massive surface cracks in the finish product. Finally, if the stucco is not cured in the proper manner, it could become brittle. Plaster or stucco walls use of one or more layers of scratch coat. Trupac x is a fantastic scratch coat material reaching 5000 psi and chemically bonding to itself in later applications. Scratch and brown coat in a three coat stucco application.
Scratch the coat use a notched trowel to scratch grooves into it, which will allow future coats to better adhere to the first layer. Smooth trowel finish stucco will tend to crack more. It is a class 1 a1 noncombustible material therefore it doesnt burst into flame or emit any. Scoring, or scratching, is done with a notched trowel. This first layer is called the scratch coat youll see why next. Variations in plaster thickness apply in uniform and trowel even structural cracks transfer of structural stresses thermal. After the scratch coat has set enough to be firm but not hard, use the rake to scratch horizontal grooves about 18 deep across the face of the base coat mortar. Apply the mortar to a properly prepared surface with a flat trowel in one. Mar 14, 2016 filling in cracks on a smooth hard trowel finish stucco. This is a traditional threecoat stucco installation not acrylic over selffurring wire mesh 2x2 wire spacing.
Exterior color coat patch is ready to use with only the addition of water. The scratch coat is applied first to provide a strong base for the system. The mix will have no body and is hard to spread, but applying it with a pump makes this practical and results in the strongest possible base coat. But the whole point of the lath and brown coat were to give a viable and strong substrate to which the finish coat could be applied, while also allowing for some minor separation of the base coat from direct contact with the. The brown coat in the stucco process is applied over the scratch coat mostly but can also be applied over cement based substrates as well, like the scratch coat.
Some fine cracking can still occur in the upper coat. Lahabra exterior color coat patch is a precolored stucco finish that is ideal for refinishing around newly installed windows, repair chipped corners and small damaged areas on standard 1620 stucco finishes. Smooth it out smooth the stucco mixture with a finishing trowel and pack it against the edge of the existing stucco surface. Ncma tek national concrete masonry association an information series from the national authority on concrete masonry technology plaster and stucco for concrete masonrytek 93a mortar, grout, stucco 2002 keywords. I say this because in vertical decorative concrete, contractors must lay up a lot more than a regular plaster application. Drying time is a factor in the development of cracks. The finish coat usually contained an integral color and was typically textured for appearance.
Now use a standard caulk gun to apply the stucco repair compound along the crack. Astm specifications, coatings, construction techniques, plaster, stucco introduction portland cementbased plaster has. Jul 23, 2008 there are several different types of stucco installations. There are several different types of stucco installations. If the scratch coat is not scratched, the next stucco coat may not adhere correctly.
Apr 10, 2020 if the scratch coat is not scratched, the next stucco coat may not adhere correctly. You could trowel more wet stucco into the cracks, but that quick repair tends to show. It works best if the mud sets up for 510 min before scratching the surface. However, they can provide a pathway for moisture and water to enter into a wall system. Teaching how to apply a skip trowel stucco finish by kirk giordano duration. Allow the top coat to cure for four days, and paint the patch with an exteriorgrade latex paint, if needed. Why new or existing stucco cracks, movement by rain thus lifting settling duration. But the whole point of the lath and brown coat were to give a viable and strong substrate to which the finish coat could be applied, while also allowing for some minor separation of the base coat from direct contact with the buildings framing members.
Apply stucco scratch brown coat and color with a skip trowel. Total thickness of the mortar, or mud should be approximately 12 to 34 of an inch. Nov 23, 2010 stucco scratch coat brown coat and finish coat same day plastering. After you have an even and uniform amount of mud on the wall, you will want to use a. Make sure that the wood strips are flat, plumb and level. You can scratch it right after you apply it to the wall but it will take a bit more control on your part to. This application of stucco is a bonding to the underlaying wire mesh and forms the base for the topcoats. Senco stucco netting wire stapler flexzilla air hose, heavy duty hi, im jason, the beard behind the camera, this is the camera i use. Then when restarting next day, wet the scratch and wet coat, butter and set more. When applying stucco over openframe wood construction, wait at least 48. A scratcher tool is used to get the horizontal lines in the cement and a green float is used.
This stucco system consists of a scratch coat, brown coat and finish coat. The scratch coat, applied by trowel, has been applied. It is usually recommended that the each of the two or three layers of stucco cure for 36 hours or more. Mist the scratch coat periodically to ensure strong curing. How to apply a mortar scratch coat for shower wall tiles. A certain amount of cracking in stucco basecoats which has simply transferred through the finish is normal. Diamond mesh used along corners and other higher stress locations. These larger ones are hard to spread stucco base coat with but do come in handy for finishing work, if you can manage them.
Standard single application float finish or scratch and doublesame day two coat application. Stucco contractor ron webber recommends a type ii plastic cement without lime or other additives for the scratch coat. October 22, 2010 by stucco plastering leave a comment. The contractor larry beilman installed 22 new marvin windows. Different trowels and what theyre used for the stucco guy. While still wet, the plaster is scored horizontally with a special metal rake or trowel to create a good mechanical bond with the second coat vertical scratching promotes cracking. The first coat should be the hardest, using a rich mix. Cracks that appear within the first 30 days after installation and are larger than 116 the thick. Identifying various cracks in stucco the stucco guy. The various layers that make up a stucco exterior wall finish contain basically the same ingredients, but are mixed at different ratios. Texture the surface of the stucco with the trowel to match the surrounding stucco.
Curing is a stucco application process that can last several days. The mixture for the scratch coat, which can be done in a wheelbarrow or large bucket, is usually. Then use a finishing trowel to paint on the damaged area and repair cracks. This coat is applied after the scratch coat and is applied using the same techniques that were used on the scratch coat. Ustucco pvx may also be used over wood or gypsum backing and as a scratch and brown coat application for traditional stucco systems. Filling in cracks on a smooth hard trowel finish stucco.
The patching of larger stucco cracks can be completed with the same finish material and color used for the existing finish. Tips on applying mortar scratch coat for bathroom tiles. If possible use texture cement finishes or specify a lamina. There are many different sizes that a pool trowel can come in and the larger one shown on the right measures 24 by 5, a massive one. The first coat, called the scratch coat, is troweled over the wire mesh to completely embed it. Twocoat stucco is used on concrete, brick, and block. Finish coat harder or denser than basecoats provide uniform density hard float of brown base coat. Take the necessary precautions to protect existing floors and flooring from drips and scratches. I have even said a scratch coat makes or breaks the job. After you have an even and uniform amount of mud on the wall, you will want to use a scarifier, notched trowel or something along those lines to make the scratch marks in the material. We applied new lath with two coats of plaster then did. Ustucco is 99% inorganic and contains 40% postconsumer recycled content making it a true green product. A darby is really just a three foot long trowel with two handles mounted on it so the user can grip it firmly. Jul 08, 2019 then use a finishing trowel to paint on the damaged area and repair cracks.
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