EIFS Repair: Synthetic Stucco and Dryvit Repair in Portland

What EIFS is

EIFS (exterior insulation and finish system) is a wall cladding built on insulation board. The trade association EIMA defines it as “a non-load-bearing exterior wall cladding system that consists of an insulation board attached adhesively or mechanically, or both, to the substrate; an integrally reinforced base coat; and a textured protective finish coat.” It is often called synthetic stucco, and Dryvit is one manufacturer of it, but it is built differently from cement stucco.

There are two kinds, and the difference is water:

• Barrier EIFS is designed to stop water at the outer surface. The Northwest Wall & Ceiling Bureau (NWCB) puts it plainly: “Barrier EIFS rely on keeping the moisture completely out of the system.”
• Drainage EIFS adds a water-resistive barrier behind the foam board and a way to drain water that gets past the surface. EIMA says these are “the predominant EIFS system in use today”, and its technical bulletin sets the test: at least 90% drainage efficiency under ASTM E2273.

EIFS arrived in the United States from Europe in the late 1960s as barrier EIFS. NWCB is blunt about barrier EIFS on houses: “Barrier EIFS cannot and probably should not have been used on wood framed structures with little or no protection from rain.”

How EIFS differs from hard-coat stucco

Hard-coat stucco is portland cement plaster: a traditional three-coat wall is 3/4 to 1 inch of cement over metal lath and a water-resistive barrier. EIFS puts insulation board on the wall with a reinforced base coat and finish over it. NWCB stresses that “There is a significant difference between EIFS and stucco, and qualified inspectors understand this and inspect appropriately.” If you are not sure which system your house has, start with a stucco inspection.

Oregon’s rules on barrier EIFS

Oregon law restricts barrier EIFS. Under ORS 701.555, a person licensed or required to be licensed by the Construction Contractors Board may not install barrier-type EIFS on a new building, or on an existing building “except as necessary to repair or replace a previously installed barrier-type exterior insulation and finish system.” The statute defines barrier EIFS as foam board, a mesh-reinforced polymer and cement base coat and a textured finish in which the layers “do not provide a means of drainage for water that accumulates behind the exterior surface”.

The residential code follows the same line: Oregon does not adopt the model code’s section for EIFS without drainage (IRC R703.9.1). In short, an existing barrier EIFS wall may be repaired or replaced in kind, but a licensed contractor may not put barrier EIFS on a new building or on any other existing wall.

How small EIFS damage is repaired

Dryvit’s published repair procedures (DS498) show what a small EIFS repair involves:

• Holes or other damage “less than 3 in x 3 in” can be patched.
• The foam is not cut all the way back to the substrate for a small patch: “Cutting off the foam all the way to substrate is not recommended.”
• Reinforcing mesh is set over the patch “overlapping the existing base coat a minimum of 1 in”.
• “Under normal conditions, finish can be applied the same day.”
• Expect a slight color difference: “Environmental conditions, dirt, and exposure will alter the existing color slightly.”

Cutting out damage is also a chance to look behind it. Sto’s repair guide notes that “the underlying substrate or water-resistive barrier can be examined”, and that where water has got into the wall assembly “a third-party envelope professional should be retained to evaluate conditions and make the necessary repair recommendations”. When the damage turns out to be in the wall itself, the job becomes stucco remediation.

Cracks in EIFS are diagnosed first

Manufacturers do not agree on how normal an EIFS crack is, so here are both:

• Sto: “Cracks are not a normal occurrence in EIFS.” and “Whenever cracks occur an effort should be made to diagnose the cracks so the cause is clearly understood.”
• Dryvit: “Most hairline cracks are aesthetic and result from normal building movement.”

They do agree on the order of work. Dryvit lists structural movement, water penetration and improper application as causes, and says: “Before proceeding, the exact cause of cracks should be determined.” Sto adds why it matters: “When EIFS with standard mesh is punctured or cracked, the system is vulnerable to water intrusion”, and on a barrier system water “is challenged to drain effectively and may damage the substrate”. More on reading cracks is on the stucco cracks page, and on what water behind the wall looks like on the stucco water damage page.

Who should inspect an EIFS house

NWCB’s advice to EIFS homeowners is to “have your home inspected by a qualified EIFS inspector who is familiar with the systems and has some formal training with the products, system, and installation procedures”, and that “Repairs should be made only by qualified individuals and have no ties with the EIFS inspector.” It also sets expectations: “An EIFS home can range from no problems to complete removal of the system. Most homes fall in the middle with some remedial repairs in specific areas of the home.”

Before any EIFS repair, check the contractor’s license in the Oregon Construction Contractors Board’s license search.