The first thing you need to know about Hardcoat STUCCO and EIFS is the difference between the two. The biggest difference is in the substrate material used. With Hardcoat STUCCO, the coating is applied over a steel mesh material attached to plywood sheathing or OSB (oriented strand board). With EIFS, there is a slightly different method. The coating is applied over a plastic mesh material attached to a Styrofoam Substrate. The Styrofoam provides outstanding energy efficiency and substantially reduces heating and cooling costs. Hardcoat STUCCO does little to aid energy efficiency but it does have a slightly higher resistance to termites and water damage.
Problems associated with Hardcoat STUCCO and EIFS include water damage and insect damage. Typically, when Stucco is applied to a house, it is done on a different day from the installation of the roofing system, windows and doors. This is one of the biggest problems. Because the stucco is applied separately from the roofing, windows, and doors, the communication between contractors is lost. There are preventative maintenance measures, such as flashing, that should be applied to certain areas of the roof, windows and doors that will protect the Stucco and the underlying wood from water. Over a period of just a few years or even less (depending on the conditions), window frames, door frames, and even wall frames can rot and deteriorate heavily, seriously compromising the structural integrity of a home.
Landscapers play a significant role in the gradual deterioration of a Stucco home as well. After the Stucco has been applied to the home and the building process is for the most part complete, a landscaping crew pulls in its bobcats and other equipment and proceeds to push the surrounding dirt right up against the bottom of the Stucco. This is NOT GOOD. It provides a clear and easy path for termites and other wood-destroying insects to enter the home and eat it from the ground up. This problem is typically bigger with EIFS than with Harcoat STUCCO and according to the termite companies. There is still some debate among Home Inspectors and industy professionals as to Hardcoat STUCCO's resistance to termites.
One thing that the Hardcoat STUCCO and EIFS applicators both tend to get wrong is the type of sealant used to protect transition joints (the spaces between the stucco and other exterior materials such as trim). Most applicators will use some type of caulk (if anything at all) for this purpose. This is a poor practice because caulk is not designed to stop water. Its main function is to stop air and noise. A good example of a sealant that should be used is Dow Corning 795 Sealant, which IS designed to stop water. This sealant should be used at all transition joints and anywhere there may be a penetration through the stucco such as utilities, hose bibs, etc.
Stucco veneer is a system! Stucco systems must:
Have proper kickouts and flashings.
Have ground clearance.
Have properly flashed decks.
Have all penetrations, transition joints, and trim completely sealed with Dow Corning 795 sealant. (or equivalent)
Have proper flashing and sealants around windows and doors.
Have clean, properly installed gutters.
Have annual inspections.