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Stucco Installation Problems

Just read an excellent article by Charles Wardell on the Journal of Light Construction website: “Avoiding the Most Common Construction Defects”. Among other problems, Mr. Wardell outlines four very common issues with stucco installations:

  1. Lack of control joints per ASTM standards that require control joints every 144 square feet
  2. Improper detailing at points where stucco meets window frames or other materials that can create cracks where water can penetrate behind the stucco
  3. Using the wrong stucco mix
  4. Poor hydration during the curing process that causes excessive cracking

He also makes it clear that it’s vital to use weep screeds with stucco and stone installations. We recommend ClarkDietrich weep screeds such as the one at this link. http://www.clarkdietrich.com/products/vinyl-weep-sill-screeds/vinyl-3-1-2-weep-screed

Stucco brought tight to a window will crack as window expands and contracts, providing an entry point for water. Photos: Dave Haines

A stucco bead should be installed around windows, doors and other points where stucco meets different products with a gap that can be filled with a backer rod.

The gap between the stucco bead and window filled with caulk to allow for expansion and contraction without cracking the stucco

Importance of a Drainage Plane

He recommends installing a “rainscreen mat” behind stone and stucco. Also called a drainage plane, this is a mesh drainage mat that creates a thin “plane” or space behind the adhered veneer. It is similar in function to the cavity in a masonry cavity wall. A drainage plane allows water behind the veneer to drain through holes in the weep screed, and also allows air to circulate behind the veneer to provide rapid and complete drying. Mortar Net’s DriPlane mesh drainage plane and the mesh drainage plane that is a part of the LathNet metal lath/drainage mat system both meet his recommendations. Learn more about DriPlane and LathNet under the Products dropdown menu above.

Read the entire Wardell article at the below link.

http://www.jlconline.com/how-to/exteriors/avoiding-the-most-common-construction-defects_o?utm_source=newsletter&utm_content=Feature&utm_medium=email&utm_campaign=JLC_073017%20(1)%20B&he=127062f63a5a72f67ecb229ff4dd56f32fa4392a 

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