Excessive cracking is stucco cracking that develops when all required or specified measures to minimize cracking are not implemented or not correctly implemented. In certain parts of america, particularly in the southwest, the predominant building siding is stucco. Smooth the mix with a finishing trowel, then pack it against the edge of the existing stucco with a brick trowel. Do your stuccoing in mild weather 50 to 80 f and work when the surface is shielded from direct sun that could dry the stucco too quickly, resulting in cracking. With smooth trowel finishes also known as santa barbara or mission finishes, even minor check cracking is more visible. Hello everyone, in this video short video i am explaining expansion of plywood or osb sheathing, if it placed next to each other which i see 8 out of 10 times on new or existing homes, this will contribute to hairline cracking especially in the summer in areas which get the majority of the heat. With smooth trowel finishes also known as santa barbara or mission finishes, even minor check. The scratch coat should be applied at a uniform thickness of 38 inch to. In some situations, it may take a structural engineer to evaluate how or why a building is moving. A certain amount of shrinkage cracking is also inevitable in stucco exteriors. Achieved using a swimming pool trowel or a pool trowel. Find the right stucco finishes and stucco texture for your. Stucco sds pdf crackresistant smooth troweled finish system. Application over woodframe construction results in more cracking than over concrete block or other more stable substrates.
The result will have a natural variation of color and texture, and small cracks from the curing process and normal building movement. Mix up enough to fill in the crack and use the trowel to smooth it out and add texture. Is usually a syntheticacrylic stucco finish, but can be achieved using a. Shrinkage cracks are the ones that look like a honey comb or spider web cracking on smooth coat stucco.
If possible use texture cement finishes or specify a lamina. Every stucco crack has its own pattern, and the nature of cracking discloses the probably reason for its development. Smooth stucco products can achieve a natural handapplied appearance over a properly prepared brown coat substrate. Stucco textures and finishes, a visual aid and insight. Squeeze the caulk into the crack, and use your dampened finger to smooth in the caulk, making sure it fills the gap and has contact with both sides of the crack. These are typically so small they are not open and cant be seen from more than five feet away. Apply a second coat and steel trowel to a smooth finish, leaving minor tool marks and open areas.
Exterior stucco all about santa barbara finish color coat stucco. Stuccoing systems stucco can be applied as a threecoat, twocoat, or onecoat system, depending on the type of stuccoing material used and the type of. Use a putty knife, smooth trowel or caulking gun to fill in the crack with latex caulk or, if it is a wider crack, use a concrete bonding material. If the cracks are wider than an 1inch, then you will need to use stucco mix. A basic rule is that the wider trowels are used for vertical type of applications and more narrow trowels are used for finishing concrete, stucco, etc.
Those cracks, which we call alligator cracking, are a performance characteristic of this type of finish coat. The purpose of stucco italiano floor repair kit is to level and smooth out uneven floors and to fill up floor cavities. Rapid set stucco mix is a premixed stucco material blended with rapid set cement, high quality plaster sand, and high performance additives. Scoop fistsize wads of wet stucco onto a brick trowel and toss them against the wire lath until its completely covered. This look is either desirable or undesirable, depending on the buyer. Stucco wall methods and choices best practices guide. Stucco trouble shooting chart stucco manufacturers association. Recommendations for smooth troweled stucco finishes omega. This smooth finish will produce lighter color shades, and any cracking will show more on a smooth wall than a textured wall. Traditional smooth santa barbara mission finish allow the application to set although. A special 2030 mix can be made when a smooth trowel mission finish is wanted. Ive done the finish here a few times, we call it the santa barbara finish, and its quite popular, the first one i did was in 1980. The sma and member plastering contractors are constantly striving to improve stucco. Trowel stucco to look like poured concrete youtube.
Common smooth troweled finish cracking patterns include thin checking in a jagged spiderweb. Repairing hairline cracks in exterior stucco a helpful. Apply the smoothing filler to the dry primed wall with the smoothing trowel. Technical bulletin 1 recommendations for smooth troweled. While its impossible to prevent cracking from all the stress forces occurring into a stucco assembly, the risk of cracking can be much reduced by installing control joints. Wet the edge of the old stucco so it wont suck moisture out of the patch and weaken the bond between old and new. Unfortunately you cant stop it from cracking, so i warn the customer that cracking is unavoidable.
Unlike smooth textured stucco which is applied with a steel trowel or even a hard acrylic trowel, texture stucco is most commonly applied with a stucco float. There are different sizes of trowels that are better for certain things, not just the length of the tool but the width as well. Stucco or render is a construction material made of aggregates, a binder, and water. The bulletpoint takeaways are that stucco cracks, its not flat, and it leaks.
Jul 23, 2008 as a result, the stucco is likely to be thinner over studs and thicker across stud bays. Other issues that cause cracking issues in plaster can be brought on by improper installation of lath, improper mixing procedures and a couple of other variables. Stuccoing systems stucco can be applied as a threecoat, twocoat, or onecoat system. Smooth trowel finish stucco will tend to crack more. Stucco is a common finish material used in residential and commercial construction, both for interior and exterior settings.
Use consistent pressure and motion to achieve the desired texture. Heres a quick guide on how to repair stucco cracks and what not to do that will help you fix the cracks without causing even bigger problems. Let the first coat dry and then apply a second coat, using the trowel to smooth out rough, cracked or inconsistent areas. Use side strokes to create an even, flat appearance. If you are interested in smooth stucco, chances are youre well aware of the cons to any steel trowel stucco application. It is manufactured from the highestgrade portland cement, hydrated lime, graded aggregates, and specific additives.
This product is ideal to be used with stucco italiano stainers. Coarse textures in the finish will tend to hide the cracks better than smooth finishes. Stucco is particularly susceptible to cracking around windows and trim boards, where its applied thicker to create architectural character. Textured stucco is best described as being applied in phases. Drag the trowel out towards the edges to smooth out the stucco and pack it down until the base layer is about 1. Natural color variations occur, because the act of troweling stucco to a smooth finish causes burn marks, where the color is accentuated and darkened. Also, the association does not recommend fog coating any smooth finish. It is used as a decorative coating for walls and ceilings, and as a sculptural and artistic material in architecture. If you have stucco cracks, its time to call a tucson stucco repair company. Now when doing smooth hard trowel finish santa barbara you can choose any of the above stucco manufactures but from our experience we think merlex stucco give the best results for the smooth hard trowel finish santa barbara.
The structural are the ones we see most because they are large and very common. A fog coat is a lightly tinted coat of stucco that matches the same existing color to enhance uniformity. Although not all cracks are objectionable, cracks in stucco acceptable to one person might be unacceptable to another person. Some of the most beautiful plaster jobs are smoothtroweled stucco with a good paint coat to bridge the fine, tight cracks that occur with that method. Cracking is one of the largest complaints from homeowners with stucco homes. Stucco mix is used on exterior plastering applications where faster set times, higher strength, superior durability, minimal shrinkage, and reduced cracking are desired. The underlying cause of the hairline wall crack may be due to problems with the walls framing, contraction or expansion of wood sheathing, settling, thermal expansion or contraction, rapid changes in temperature, weak areas in the wall or abnormal. Floors cement floors floor plaster stucco italiano. Certain fine or smooth textures accentuate cracks in stucco, while heavier textures tend to hide stucco. Repair cracks in smooth to mediumtextured finish stucco by applying a fog coat of the same material. The two types of stucco cracks are structural and shrinkage.
The role of control joints is to deflect the movement stresses, minimizing the development and spread of stucco cracks. Hello everyone, in this video short video i am explaining expansion of plywood or osb sheathing, if it placed next to each other which i see 8 out of 10 times on new or existing homes, this will contribute to hairline cracking especially in the summer in areas which get the majority of the. Also,burn lines and color mottling can be expected. Apr 05, 2020 drag the trowel out towards the edges to smooth out the stucco and pack it down until the base layer is about 1. Stucco is applied wet and hardens to a very dense solid.
Colors can be added directly to the wall to achieve a mottled look. Or explore our complete range of stucco and plaster wall finishes. Use of bonding agents over santa barbara finish may or may not cause excessive check cracking when a smooth finish is applied over the bonder. From time to time, even stucco manufactured and installed correctly will crack. Stucco is usually white, but special color blends are available. Tsib recommends further decorating of this finish with an approved coating.
Stucco italiano floor repair kit is a two component polymer modified cementitious product. Jul 17, 2017 cracking in stucco or dryvit walls happens when there is more stress placed on the wall than the material can withstand. Expansion, wind and stress all play vital roles in why cracking occurs. Nov 08, 2014 horizontal cracking on new stucco homes, cracks caused by plywood. Colortek smoothcoat exterior stucco omega products. Sep 12, 2019 some of the most beautiful plaster jobs are smoothtroweled stucco with a good paint coat to bridge the fine, tight cracks that occur with that method. Name santa barbara finish color coat stucco type semi smooth portland cement finish for exterior surfaces technical bulletin 102 division 9 finishes, plaster and stucco revised 8714 trowel or spray applied merlex santa barbara finish exterior stucco is a premium quality portland cement based. Find the right stucco finishes and stucco texture for your siding. Name santa barbara finish color coat stucco type semismooth portland cement finish for exterior surfaces technical bulletin 102 division 9 finishes, plaster and stucco revised 8714 trowel or spray applied merlex santa barbara finish exterior stucco is. If stucco finishing is done using a trowel, the walls need to be cool and moist with no. How to apply stucco over old stucco home guides sf gate.
A stucco expert can generally determine the cause of some cracks, but at the same time, some cracks can be puzzling. Repairing stucco cracks, why new stucco walls can crack youtube. If you are interested in smooth stucco, chances are youre not exactly well aware of the cons to any steel trowel stucco application. The first phase is applied as the foundation or basecoat for the overall desired stucco texture. Depending on size, cracks can run the gauntlet from invisible to unsightly to the cause of major water intrusion, if they. Once it is applied, then wipe off the excess and allow it to dry. You can alternate between using the brick trowel and finishing trowel as you smooth the stucco. Once the cracks in the stucco ceiling are repaired, you can paint the ceiling a matching color. It sounds counterintuitive, but youll probably need to make the crack wider. Is very hard to patch and has a tendency to crack more than other finishes. Cracking is inevitable when it comes to stucco, just like any type of cement based product.
Whether applied as exterior siding or as a finish for interior walls, the ageold material requires little in the way of ongoing maintenance. When you steel trowel stucco, this action seals in the moisture in or not allowing the stucco walls to breathe as well, thus this process often produce more hairline cracking than other methods of. The underlying cause of the hairline wall crack may be due to problems with the walls framing, contraction or expansion of wood sheathing, settling, thermal expansion or contraction, rapid changes in temperature, weak areas in the wall or abnormal vibrations in the ground. Common smooth troweled finish cracking patterns include thin checking in a jagged spiderweb pattern and stress cracks emanating from corners of doors and. A certain amount of cracking in stucco basecoats which has simply transferred through the finish is normal. Cracking in stucco or dryvit walls happens when there is more stress placed on the wall than the material can withstand. The colors are beautifully variegated due to the hard trowel application. All stucco cracks are the result of stucco releasing stresses placed on it by shrinkage, expansion or other movement. There are heavy skip trowel textures popular in the 60s and 70s and finer ones more popular today, sometimes referred to as lace or spanish lace. Clean off loose stucco and dirt with a stiff brush. Burn marks and catfaces can also occur in the process of troweling the material down to a smooth finish. Certain fine or smooth textures accentuate cracks in stucco, while heavier textures tend to hide stucco cracks. Aplc recommends either applying an exterior bonder that meets astm 932 standards and a precoat or sand blast or etching.
To create a harmonious look with the rest of your siding, you will need to apply stucco, applied with a putty knife or trowel. Fine sand finish or smooth finish textures accentuate cracks in stucco, while heavier textures tend to hide stucco cracks. Stucco is made up of portland cement, lime, sand, water, and additives applied in several layers over wood or metal lath. Cracking in a stucco walls, stucco shrinkage cracks youtube. Common smooth troweled finish cracking patterns include thin checking in a jagged spiderweb pattern and stress cracks emanating from corners of doors and windows. Jason and i have over 850 original, educational, and free youtube videos. Our recommended tools, we dont need the most expensive tools, just the best built and proper trowels. For these small cracks, get a flexible, paintable, exteriorgrade. Because of these serious risks that cracked stucco can entail, it is important to deal with it promptly. Easy ways to repair peeling stucco with pictures wikihow.
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