Much Ado About Stucco
Much Ado About Stucco
By Michelle N. Delehanty, PE, PMP
MDC® Consulting Engineer
In recent years, the popularity of stucco siding for houses has soared. Or, depending who you ask, it’s the notoriety that has increased so steadily over the past decade. Good or bad, stucco is being talked about among builders, homeowners, and even in the news.
Stucco is a durable, eye-catching, and cost effective material that has been used for centuries. This option is both attractive and versatile to consumers in that it can be applied to many different home styles. Stucco has been known to stand the test of time; however, way it is used today – in composition and assembly – isn’t necessarily your grandfather’s stucco.
History of Stucco
In the evolution of building materials, Portland cement stucco is a relative new comer. It was patented in England in 1824, and not perfected to its current state until about 50 years later. Portland cement stucco is stronger, harder and quicker curing than traditional lime plasters, lending itself to be the most commonly used cement stucco of today’s construction, along with plethora of synthetic stuccos that mix Portland cement and acrylics or other hydrocarbons.
So what has changed with the subtraction of lime from the stucco mixtures? The Portland Cement Stucco, although stronger and more convenient, is more brittle, and therefore more likely to crack under some load conditions. The lime gave the stucco a natural ability to “heal” stress cracks that develop. Additionally, the Lime Stucco is moisture permeable. This statement would lead you to believe that Portland is better when it comes to moisture. This is not really the case, because with Portland cement stucco, there is a greater chance that the moisture will become trapped in the wall, as opposed to permeating back through the Lime stucco and evaporating into the outside air.
With the development of today’s stucco technologies over the past few decades, the code has taken awhile to catch up. Many of the homes built 10 years ago were based on codes that hadn’t been updated since the early 90s. As a result, the construction of these houses can sometimes be perceived as unfit for today’s standards.
Typical Stucco Siding Assembly for Newer homes
Homes built in the last quarter century are typically framed by 2×4 or 2×6 studs. On the interior of this framing is ½” gypsum wallboard, or drywall as it is commonly referred, laid out in four foot by eight foot panels with joints taped and a painted finish. On the exterior of the drywall, a vapor retarder and insulation are required, usually a product with both elements is used – fiberglass batt insulation with foil or kraft paper lining is included and installed in the cavity spaces between the stud framing. Both the vapor retarder and insulation have varying levels of moisture and temperature resistance, respectively, and are specified based on the code and climate when the house is designed.
MDC® Principal Selected to Participate in the 2013 Philadelphia Leadership Exchange
MDC’s Mitchell Swann, PE, was selected to participate in the 2013 Philadelphia Leadership Exchange on October 24th & 25th, 2013 in Philadelphia. This year’s theme was “Innovation and Collaboration Around Shared Agendas.”
The Greater Philadelphia Leadership Exchange is an initiative of the Economy League to develop leaders of business, civic, and government organizations into visionaries dedicated to making Greater Philadelphia a world class region. Through in-region programming and out-of-region learning visits, the Leadership Exchange exposes leaders to best practices, forges new connections across sectors and industries, and deepens participants’ understanding of Greater Philadelphia’s potential.
Participation in the Leadership Exchange is a competitive process with a goal of representing the geographic, demographic, sector, and industry diversity in the region. To be eligible, applicants must live and/or work in the Greater Philadelphia region and serve in a leadership role in a business, nonprofit, or government organization.
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