Certified Stucco & EIFS Inspections

Several factors play into this issue, including improperly trained installers.

1. Decreased energy across assemblies due to thermal resistance. Our modern, air-tight, structures restrict energy flow (energy efficient) which means when our walls get wet, they cannot dry out. If we are going to restrict the ability of our building materials to dry, we need to also restrict the wetting potential.
2. Stucco is a porous material, and it retains moisture. When the sun comes out after a rain, the solar energy drives the moisture inward.
3. Unlike conventional plywood, gypsum is too vapor permeable and OSB (oriented strand board) is vapor impermeable. This means when gypsum or OSB gets wet, it stores the moisture rather than wicking it away. OSB is excellent at repelling moisture in the short-term, but systemic exposure to water is disastrous. Stucco bonded to house wrap, which is bonded or in contact with OSB, prevents the OSB from redistributing water at the surface (the only way it can). Plywood can redistribute moisture both outward and inward. Plywood becomes "vapor permeable" when wet; OSB does not. So, as the board gets wetter and wetter, it decays the material, and it begins to crumble. Now the moisture penetrates the OSB through the hole or cavity and damages the interior wall.
4. Unlike asphalt-impregnated moisture barriers such as tar paper, impregnated felts, and Kraft paper, stucco bonds to our modern house wraps and if not properly protected and installed, it loses the drainage gap which is critical when using OSB. Older building papers were more robust; they weighed more and had more cellulose content. The dimensional instability of the cellulose prevented stucco from bonding to the house wrap, which gave us a modest drainage gap. Since stucco does bond with plastic house wrap, we have lost that gap. There must be a bond break between the stucco and the moisture barrier and wall sheathing. Using two layers of modern plastic MRB is better but still not sufficient to prevent bonding of the stucco through the MRB to the wall sheathing. We need vapor retarders — not vapor barriers!

Many home inspectors will incorrectly point out missing control joints, improper thickness, or try to cite a reference in an ASTM publication as the root cause of stucco problems, but in many cases they will be wrong. Perfect adherence to ASTM guidelines, which may be referenced in our building code, does not guarantee your home will not have a moisture issue. If the stucco cladding was installed completely wrong, it may need to be removed. Missing control joints may result in increased stress cracking, but it has very little to do with hidden or trapped moisture.

Here is an example of what we should be doing to prevent moisture intrusion in our homes:

At Property360, we know that when major damage is found in stucco wall claddings, the damage often occurs in the "field of wall" rather than around doors, windows, or corners. When we have water damage in the open middle sections of walls, it is not related to a missing control joint or a rain diverter or even the thickness of the stucco. We have an issue with missing air gaps which are necessary to prevent wall sheathing from getting wet. We also have delamination caused by improper adherence to lath, or other issues that will require an inspector who truly understands stucco to evaluate.

If you are buying a home that has stucco or adhered masonry veneers (stone/brick), you need to hire a home inspector who has verifiable experience and knowledge of stucco. You simply will not get that from an inspector who does not have building experience. If you hire an inspector who has never built a home, who has never installed stucco, or who has not taken the time to learn stucco, you are taking a big risk.

You cannot rely upon the referrals provided by your real estate agent. Agents rarely have knowledge of stucco and, unfortunately, they normally do not take the time to properly evaluate their referrals. Generally, they simply refer the cheapest inspector regardless of experience, knowledge, or qualifications. Now is not the time to try to save a few bucks on an inspection!

• 1824: Portland cement invented in England by Joseph Aspdin (British patent 5022 Artificial Stone).
• 1871: Portland cement first manufactured in Lehigh Valley, Pa., USA.
• 1911: First independent testing performed by the Bureau of Standards to improve quality regarding metal lath corrosion.
• 1916: Portland Cement Association is formed.
• 1920: First standard issued by the American Concrete Institute.
• 1931: Mortar cement developed that does not need lime.
• 1953: Weep screed developed to control moisture.
• 1955: SMJS control joints developed (double V).
• 1967: Uniform Building Code first includes stucco foundation drainage flashing.
• 1969: Dryvit introduces EIFS to America (developed in Germany for reconstruction after WWII).
• 1971: ANSI issues A42.2.
• 1977: Powerwall, a one-coat stucco system, marketed by William Nichol (later acquired by STO Corporation)
• 1980s: One-coat stucco wall assembly, including continuous insulation board, first introduced in response to the energy crisis.
• 1986: ASTM C926 issued (successor to ANSI A42.3-71).
• 1990s: Fabric-reinforced lamina and acrylic finish coats from EIFS systems are installed over conventional stucco base coats for crack control.
• 2000: International Building Code first codifies ASTM C926 and ASTM C1063 and other ASTM standards wherever the IBC is locally adopted. (Note: not all local building departments adopted the standards).
• 2008: Water-management assemblies and lath-accessory components with integral flashings to integrate with the water-resistive barrier (WRB) invented by Don Pilz and introduced by Cemco.
• 2011: ASTM E2266 Standard Guide for Construction of Low-Rise Frame Building Wall Systems to Resist Water Intrusion, was published along with stucco guide details.
• 2014: Continuous insulation barrier became a building code requirement. ASTM 1063 is referenced in Ch. 35 of the 2014 Florida Building Code.

Most stucco cracks are related to stress on the wall assembly. They may, or may not, be a potential moisture issue. The most common broad categories of cracking relate to the following:

• Substrate support and movement
• Stucco lath and lath accessories installation
• Stucco mix design
• Stucco thickness variations
• Stucco curing
• Stucco shrinkage and thermal movements
• Stucco finish assemblies
• In-service environmental conditions