December 1996 Edition

Synthetic Stucco Problems

We have been watching the news lately with the concern about synthetic stucco homes. How can we tell if our stucco was properly installed and how do we tell if there is a moisture problem behind the stucco. 

Synthetic stucco or “EIFS” (Exterior Insulation Finish Systems) has been used on thousands of Atlanta homes. It differs from “real” or “hard” stucco by utilizing an insulated sheathing board and a fiberglass mesh. The finish is a synthetic material made to look like real stucco.  

The problem is water penetration, allowed to enter behind the EIFS which does not evaporate and is trapped. The moisture attacks the wood sheathing, and in the worst cases, the wood framing. Many of the moisture problems appear to be around the areas where the EIFS butts against the wood trim and at the roof flashing. Most of the manufacturers have detailed installation instructions, but unfortunately these are ignored by some installers.  


Flashing is required where any vertical wall meets the roofing shingles. Flashing is sheet metal that is installed behind the wall material and extends out underneath the roofing shingles. This prevents water from entering the structure at the intersection of the wall and roofing.


Stepped flashing is commonly used at sloped vertical walls to insure any water that runs between the roof shingles and the flashing will be diverted out on top of the lower shingles, preventing water from running under the remainder of the shingles. Some of the installers are still using continuous flashing which is not equal.   

With most sloped roof flashing, water can continue down to the end of the flashing. If this happens, it could run behind the wall covering and into the wall cavity. The end of the flashing must turn out to ensure any water will be diverted to the outside of the wall. Most homes do not have diverter or “kickout” flashing installed. If your home does not, it would be a good idea to have it installed.  


The bottom edge must be finished on any EIFS system. If the system terminates directly on top of the roof shingles, you can be assured it is not properly finished along the bottom. EIFS must be held off of the shingles by 2” (see diverter drawing) to allow proper wrapping of the mesh and finishing of the bottom edge. We see many cases where the builder installs the roof shingles first in order to “dry” in the roof as soon as possible. The exterior wall finish is installed at a later date with the finish actually sitting on top of the roof shingles.  


Another common problem we find is improper installation at the exterior wood trim, especially at doors and windows. Most of the time EIFS is butted directly against the wood trim. A crack appears and this could allow moisture to enter. A minimum of a 1/2” joint is required between the EIFS and any dissimilar material. This joint is filled with a foam backer rod and then covered with a good quality caulking or sealant.


It would be a good idea to inspect any wood trim to see if  cracks have developed. If they have, just caulking over the cracks will do little to seal the cracks in the long run. When the wall material moves, the caulking will crack. A joint will have to be installed where the caulking will have something to bond to and also the caulking should be thick enough to move with the expansion and contraction without splitting or cracking.  


Decks are another area for concern. It is common to have the decks simply installed over the EIFS. Any breaks in the finish or around bolts could allow water penetration. The CABO One And Two Family Building Code requires flashing to be installed where any deck is attached to a wood frame structure.


EIFS should terminate 2” above the floor decking, again, for the proper wrapping of the mesh and finishing of the bottom edge. The finish may continue under the deck header provide proper cap flashing is installed. This installation will prevent any water penetration into the structure. 


When EIFS continues below ground level, any opening in the  finish  could  allow  wood  destroying  organisms, such as


termites, to enter through the insulated sheathing into the wood framing. We often find the bottom lip is not properly finished and the insulated sheathing is actually exposed.  

EIFS should terminate 6” above the finished ground level and the bottom lip should be properly wrapped and sealed. This will allow a visual inspection of any wood destroying organism crawling up the outside of the foundation.  Some of the Pest Control Companies are refusing to issue a “Termite Letter” on any structure that has EIFS or slab insulation below grade. 


The only way to tell if moisture has entered the structure is with a special moisture inspection. Most of the inspections consist of punching holes through the finish so that moisture probes may be inserted into the framing. Some new moisture meters are becoming available that can read the moisture, behind the EIFS, without penetrating the surface. Any moisture reading over 20% is cause for alarm. Since the length of the inspection is proportional to the amount of moisture found, the time could vary from 2 hours to 16 hours and the price from approximately $200.00 to $1,600.00.

If you have a question, change of address, comment, home tip or would like to send Home Tips to your clients, send your letter to Home Tips, Christian Building Inspectors, Inc., 3697 Habersham Lane, Duluth, Georgia 30096. You can E-Mail your questions to us at We reserve the right to edit questions for length.

Thought For The Season

May Your Christmas Be Filled With All The Love, Joy And Peace That Comes In Celebrating The Birth Of Our Lord Jesus Christ.

A Tip Of The Hat To:

All The People Who Referred Us In 1996

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