PROBLEMS WITH SYNTHETIC STUCCO

	Over time, moisture between the synthetic stucco and the wall will cause rot damage to the wall structure.

When new or unfamiliar products or technologies are introduced into residential construction, problems sometimes develop.

Properly speaking, this product is known as an Exterior Insulation and Finish System (EIFS, pronounced "eefs").

Rigid foam insulation board is attached to the walls and covered with a reinforcing mesh and several coats of polymer-based material. The final coat is textured to simulate the look of stucco. EIFS has been used in commercial construction in the United States since 1969 and in Europe since the 1950s.

While it has the appearance of stucco and is installed similarly, it has some very different properties.

One of the most important differences is that Synthetic Stucco is an effective vapor barrier.

Water vapor will not pass through it. Traditional stucco consists of sand and mortar installed over an extruded wire mesh. It is a porous material which will permit moisture to move both in and out of the wall.

A further difference concerns the method of installation. Synthetic stucco is applied directly to the sheathing using an adhesive. Traditional stucco is applied over a mesh, installed with standoffs, allowing some space behind the stucco.

What's the problem?

As with so many other problems in residential construction, water is the ultimate culprit because Synthetic Stucco does not breathe. Moisture cannot exit the cavity and is absorbed into the wood framing. Over time, this will cause rot damage to the wall structure. The substrate (the material to which the insulation board is attached) can also develop problems if it is subjected to moisture, and is not designed for such purposes.

In the much-publicized cases in the Wilmington, NC area, the source of the water is reported to be cracks and gaps in the building envelope. Poor or damaged caulking at joints between the EIFS and window and door casings and exterior trim has permitted water to enter.

Studies of buildings in other locations (Kansas City, MO, Carbondale, IL, Atlantic City, NJ, and eastern Massachusetts) suggest that this is not a regionalized problem.

As we understand it, the Exterior Insulation Manufacturers Association (EIMA) presently places the blame on poor construction practices, low-quality windows, the coastal environment of Wilmington, and building codes which may require the installation of a vapor barrier on the heated side of the wall cavity. Builders on the other hand, are claiming inadequate and/or unrealistic installation instructions and unrealistic maintenance expectations.

Not Just an Eastern Problem

Although problems with Synthetic Stucco have been found primarily in areas of the south, east and midwest where moisture and humidity problems are most severe, care is also warranted in other parts of the country.

The polystyrene foam board used is subject to degradation from ultraviolet radiation. That is why the foam is always coated. However, in some spots which are hard to get at, such as at the roof-line or around second story windows this coverage is spare or non-existent. The result can be rapid and premature degradation of the entire wall. When the insulating board is in contact with the ground (no longer allowed in many areas) and the bottom edge is not properly sealed, a perfect path of entry for termites or carpenter ants is created.

Inspection Options

What condition is the home in?

What is the potential for future problems?

Should the stucco be replaced now?

Is there any structural damage?

Even if the stucco is in good condition now, is the maintenance going to be an overwhelming task?

A visual inspection is useful in assessing the propensity for concealed problems and can identify certain existing damage. Unfortunately, visual inspections are not conclusive.

Visual inspection

Visual inspection of the interior surfaces can help define the likelihood of water penetration in the wall. Avenues for penetration include flaws in the moisture protection of the building. More conclusive evidence of water penetration include signs of deterioration or growths.

Avenues for Moisture Penetration

split or missing caulk seals

uncaulked settlement cracks

nails penetrating the stucco

Evidence of Water Penetration Include

water stains on the interior drywall

softening or rot damage of window and door trim

moisture or fungus growth on the interior of wall sheathing or framing visible in the crawl space

elevated moisture level readings on baseboard trim.

Only in the most severe cases, however, would structural damage be apparent from a visual inspection.

It is very important to understand that the absence of visual evidence does not confirm that there is not water penetration or no damage.

The visual inspection should be considered a gauge to help determine if more invasive investigation is warranted.

Invasive inspection

Invasive inspection includes measuring the moisture level in the sheathing and framing underneath the stucco and insulating board siding.

This is accomplished with probes through the siding, cutting inspection holes in the interior drywall, or actual removal of part of the stucco surface. Invasive inspection is recommended if water stains, rot damage or other evidence shows a clear indication that there is water penetration of the wall. Invasive inspection may also be recommended in cases where there is no clear indicator, but there are significant deficiencies in the moisture protection envelope. Certain municipalities recommend invasive testing for all homes with EIFS siding.

Moisture testing is best left to trained professionals and should be performed according to a specific plan or "map" of the most vulnerable areas. Simple random testing is not sufficient. Areas with moisture levels above 19 percent will require attention.

THE SOLUTIONS

Provided that there is no water in the wall and no damage, short-term measures to prevent problems are limited to diligent caulking of all exterior joints and holes where water could get through the stucco surface. Unless there is already major structural damage, the stucco does not have to be removed. The addition of gutters may also help keep water off the exterior walls except in a blowing rain.

As of this writing, neither the EIFS industry, home builders, nor code enforcement officials have offered practical, long-term solutions to the problem.

Water is going to get in the wall cavity eventually. The proper solution is one which addresses this fact. One possibility is to use a system of flashing and weep holes (small holes at the bottom of the wall) similar to those used with brick veneer to permit water to exit the wall.

SELLING A HOME WITH EIFS

For the seller and real estate agent, the primary issue is to make sure that the condition is fully disclosed without raising undue or unreasonable alarm.

Recent media reports showing workmen ripping the stucco off of entire subdivisions can create considerable and often legitimate concern. Overcoming this sensationalism can be a daunting task and requires careful education of both sides of the transaction.

Once the existing condition and likelihood of concealed or future problems is clearly understood, the potential buyer can assess the risk and make an informed decision to proceed.

Criterium Engineers, Copyright © 1999

Close Articles of Interest