Typical control joint location at corner of window. All of these factors combine to make stucco in one part of the world vary from stucco in another part of the world and stucco is truly worldwide. ASTM recognized the sand dilemma and made a provision in the standards to allow any sand that has a proven track record in that specific market. Think about it: Stucco is just sand, cement and lime, pretty simple, right? That is until you consider how many types of cements there are on the market, as well as lime, lime replacers and sand selection. While seemingly basic and simple, it can be very complex and have hundreds of variables. This can result in bubbles or blisters in the coating.Ī UNIQUE MATERIAL It must be understood that stucco (Portland cement plaster) is unlike any other building material that we use today. Most elastomeric coatings do not allow a vapor to pass through the coating. Small amounts of moisture that can find its way behind the stucco will try to exit as a gas through stucco. This does not mean we should close our minds to new products and procedures, just proceed with “cautious optimism”-there may be some long-term issue to consider in an attempt to avoid a short-term problem.įor example, while it may seem that using an elastomeric rubber-type coating is an easy solution, there are long-term vapor permeability issues to consider that may not be so rosy a few years down the road. Remember, if it sounds too good to be true, it probably is. Cement stucco has been around a long time and many have claimed to have the magic answer.
Cracks are a result of stress and many of these certainly come from outside sources and are beyond the plastering contractors control.īe wary of quick-fix products or seemingly easy solutions. To minimize cracks requires a working partnership with the general contractor and other trades. Wall and ceiling contractors should advise owners that some cracks are possible, even likely, but that he will do all in his power to minimize the cracking as much as possible.
Never forget they have choices in exterior claddings and not choosing stucco decreases your future work. In the long run, it will sway people away from selecting stucco as a cladding. This tactic rarely works in the short term, as owners hire consultants to investigate why the cracks have occurred and the courts rarely side with the contractors using this poor defense. He believes this minimizes his responsibility for due diligence to minimize the cracks as much as possible. While some hairline cracking should be expected, too many plasterers make statements like, “I will make a guarantee but the stucco will eventually crack.” This purely negative statement is usually an attempt by the plasterer to get the customer to accept all cracks. The problem is that this myth or position that all stucco jobs cracks is propagated by too many plasterers trying to use this statement to explain away poor planning, a lack of knowledge, bad plaster mixes or bad practices. It is certainly possible for a building with stucco to have no cracks, but in all probability some hairline cracking is inevitable. Unlike some things in life that are either black or white, right or wrong, stucco is subjective and typically falls in the realm of shades of gray. Plastering Myth Number 2: "All Stucco Jobs Crack!" I know you must be thinking, “Wait a minute, how can both statements be myths?” While this may seem like we are trying to have it both ways, it is not. Instead of simply regurgitating the same information that has been published many times or quote established standards, I will try to provide realistic goals and information you can use. The purpose of this article is to educate and assist contractors, foremen and journeymen in a better way to handle the problem of hairline cracks in stucco. Depending on the consultants hired, the amount of money the plaintiff is willing to spend and what concessions the contractor is willing to make short of litigation, the problem can be costly-in time and money. The process is then to scrutinize the materials used, remove large sections and measure every fastener for spacing, all in the hopes to find a way to pin the problem of cracking. When tempers fly and no resolution seems likely, a private consultant can be hired to take core samples and ship them off to the lab for a petrographic analysis. We try every new product and technique but yet still seem to find ourselves on site with the designer, owner and general contractor pointing fingers at one another for cracks in stucco. Every contractor who has anything to do with stucco knows the frustration of hairline cracks that are inherent with a cement stucco system.
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