It seems every 10 years, the home-building industry has another scare. In the 70’s, it was lead paint. In the 80’s, it was radon. In the 90’s, mold was the culprit. Now it's stucco. Most of that fear is based on Synthetic Stucco – also called EIFS (“Exterior Insulation and Finish System). Because EIFS doesn’t “breathe,” it creates ideal conditions for moisture within the walls, causing the wood framing to rot. The most famous brand name for this system is Dryvit.
To make matters worse, most building codes require vapor barriers, even for EIFS, which worsens the problem. In 1995, EIFS homes in North Carolina developed serious moisture damage. The lawsuits that followed have made buyers, agents and insurers hyper-sensitive to the risk. Fortunately for Main Line home buyers, most synthetic stucco was used in the South.
While most synthetic stucco is applied over insulation board, traditional stucco, which is applied over metal lathe, has been popular for more than a century. It performs well in all climates, and is durable, economical and fire resistant. Note: poorly installed window flashing, a fairly common problem, can cause water to penetrate the walls of both EIFS and traditional concrete stucco.
The Seller Disclosure form requires disclosure of EIFS systems. However, many homeowners don't know what it is, or if their home has it. So it's imperative that buyers take steps to be sure. True stucco experts are rare and expensive ($1500 and up), and the inspection usually involves penetrating the walls, which many sellers will not permit. But in my experience, a good inspector can usually tell if water has penetrated the walls and if there’s wood rot or mold, although it may require removing some interior wall sections. A more economical option is to test the home interior for mold spores – but that would not disclose non-moldy wet wood behind walls.