Housing Giants - July 24, 2008 - (Page 18) process These cracks can run deep, exposing the building materials beneath the stucco, such as housewrap, to the elements. Because these materials aren’t built to withstand prolonged exposure, water will eventually penetrate them and move toward the interior of the home. In extreme cases, these larger cracks can also shear the metal lath, which places more stress on the rest of the stucco system, potentially causing additional cracking. Some of the most common errors that cause stucco to crack are relatively easy to prevent. Let’s look at three. Common Error no. 1: InsuffICIEnt sand Stucco mix consists of three main ingredients: cement, sand and water. The mix proportions are carefully controlled to create a stucco mix that, when adequately hydrated, allows each coat to relieve stresses through a dispersed pattern of micro cracks prior to the application of the next coat. Out of the three ingredients, there’s a greater opportunity for error when it comes to the sand. When there isn’t enough sand in a coat, the cement paste shrinks too much. The excessive shrinkage puts too much stress on the coat, leading to deep cracks on the surface of the wall. These cracks frequently occur at locations where the cross-section of the stucco is reduced, such as at a window. When there’s too much sand in the mix, water has to be added to maintain workability, which reduces the water-to-cement ratio of the mix, weakening the stucco. If too much water is added, the stucco loses cohesion and slumps on the wall. The thickness of the stucco on this wall is inconsistent, exposing the metal lath. After proper hydration, the pH level should be no higher than 10 when proceeding to the next coat. 18 HousInG GIants.7.24.08 www.HousInGGIants.Com http://toolbelt.buildiq.com/topics/exterior-finishes/stucco-3-coat/cracking.aspx http://www.cement.org/stucco/materials.asp http://www.housinggiants.com
Table of Contents Feed for the Digital Edition of Housing Giants - July 24, 2008 Housing Giants - July 24, 2008 Contents Viewpoint News & Moves Process Critical Management Series: Part II Housing Giants - July 24, 2008 Housing Giants - July 24, 2008 - Housing Giants - July 24, 2008 (Page 1) Housing Giants - July 24, 2008 - Housing Giants - July 24, 2008 (Page 2) Housing Giants - July 24, 2008 - Housing Giants - July 24, 2008 (Page 3) Housing Giants - July 24, 2008 - Housing Giants - July 24, 2008 (Page 4) Housing Giants - July 24, 2008 - Contents (Page 5) Housing Giants - July 24, 2008 - Contents (Page 6) Housing Giants - July 24, 2008 - Viewpoint (Page 7) Housing Giants - July 24, 2008 - Viewpoint (Page 8) Housing Giants - July 24, 2008 - Viewpoint (Page 9) Housing Giants - July 24, 2008 - News & Moves (Page 10) Housing Giants - July 24, 2008 - News & Moves (Page 11) Housing Giants - July 24, 2008 - News & Moves (Page 12) Housing Giants - July 24, 2008 - News & Moves (Page 13) Housing Giants - July 24, 2008 - News & Moves (Page 14) Housing Giants - July 24, 2008 - News & Moves (Page 15) Housing Giants - July 24, 2008 - Process (Page 16) Housing Giants - July 24, 2008 - Process (Page 17) Housing Giants - July 24, 2008 - Process (Page 18) Housing Giants - July 24, 2008 - Process (Page 19) Housing Giants - July 24, 2008 - Process (Page 20) Housing Giants - July 24, 2008 - Process (Page 21) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 22) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 23) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 24) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 25) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 26) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 27) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 28) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 29) Housing Giants - July 24, 2008 - Critical Management Series: Part II (Page 30)
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