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Stucco Concerns

 

You can maintain the curb apeal of your property with proper care and maintenance of the exterior cladding of your home.

The ideal situation would be to have the Exterior Cladding on your home  inspected as it is being applied to the house.   However, that may not be possible in many situations.  An inspection by a Certified Third-Party EIFS Inspector or Certified Moisture Analyst would provide the necessary information to assist you in establishing the condition of and maintaining the integrity of your home.  The purpose of this inspection is to look for visible installation flaws, inadequate water diversion, sealant failures and, if necessary, conduct moisture readings as appropriate using electronic moisture devices and substrate evaluation.

Moisture intrusion problems are not limited to stucco claddings.  Time of exposure coupled with the quantity of water, result in problems for any home.   In our area, many of the homes combine stone, fiberboard, wood, cement board or vinyl siding, brick, and various types of stucco.  For example, hard coat stucco exteriors may have stone veneer below decorative bands along with a variety of other decorative features. 

Barrier PB EIFS Exterior:
When you hear people talking about problems with EIFS, this is the style of EIFS typically having the problems discussed.  The objective is to prevent moisture from entering the system.  Barrier-type EIFS is a system that relies entirely on its outside surface to prevent water penetration and moisture intrusion. Therefore, excellent design, compatible quality materials and excellent workmanship are required to produce a weather-tight and long-lasting system.

Moisture Intrusion may occur at the following:

Windows and doors - Points of concern to be evaluated

  • Look for peeling paint, evidence of water damage on the interior wall, staining on the exterior.

  • Check for calking around window sills and door jams.  Stucco manufacturers recommend a specific sealant for their windows

  • Is sill pan flashing present or is it needed?

Flashings:

  • Flashings at appropriate places direct water away from the house.

  • Missing, improper or unsealed flashings where roof lines terminate into an EIFS wall will allow roof run-off to be dumped directly behind the EIFS.

  • Water must be directed away from windows, decks, gutters, etc.

Caulking:

  • Penetrations in the EIFS at decks, hose bibs, dryer vents, light fixtures, satellite dishes, etc. must be properly sealed with the appropriate sealant.

  • All joints where EIFS meets a dissimilar material must be sealed  with the appropriate sealant. 

  • Existing sealants should be adhered, soft and flexible.

Installation Issues:

  • Foam insulation should be at least 6 inches above soft grade and two inches above hard surfaces. This prevents wicking of moisture and eliminates a termite path into the structure. 

  • The foam substrate should be properly back-wrapped in order to provide for proper protection of the exterior system. 

  • The usage of backer rod and sealant is necessary for the proper construction of an isolation type of joint such as windows, expansion joints and grade terminations.

  • EIFS used on non-vertical surfaces such as trim and decorative touches should have a sloping surface to prevent standing water.

All EIFS manufacturers have details and procedures that builders and applicators are expected to follow.  Installation details are similar among the various EIFS products; however, there are some differences.

Moisture Drainage PB EIFS:

This is the second generation of PB EIFS.  The difference is that MD PB EIFS has a secondary moisture resistive Barrier to control incidental moisture that gets through the EIFS Exterior Barrier and permits it to drain ou the bottom of the system.  The MD EIFS should be installed such that all water will again be shed at the exterior surface and a  secondary moisture resistive barrier to handle any moisture that gets past surface barriers.

Hard Coat Stucco ( Traditional or OCS)

Hard Coat Stucco (HCS) has been used for decades, traditionally three coat stucco has a long history that is well accepted and defined in the Model Building Codes.  The newer One-Coat Stuccos (OCS)  are thinner with proprietary mixes that require code body evaluation service reports for local building officials to review and allow use of products in their jurisdiction. 

Traditional Stucco facts:

  • A Moisture Barrier is required on top of moisture sensitive substrates such as wood, gypsum, etc.

  • Three coats or layers with a total thickness of 3/4 of an inch or more - Scratch Coat,  Brown Coat, and Finish Coat.

  • Metal Accessories - Casing Beads or Stops or Grounds, Weep Screeds, Corner Aids, and Control Joints or Expansion joints at 144 square feet.

  • Flashings are required as a part of weatherproofing the system.

  • Vulnerable to excessive cracking.

  • Details are well developed; see Northwest Walls and Ceiling Bureau Stucco Resource Guide.  

One-Coat-Stucco is a newer stucco system that is very similar to traditional stucco but with some advantages.  It provides design flexibility, durability and water management. It can also  be finished in a variety of ways including premixed colored cement stucco finish coats, elastomeric coatings and paints or even acrylic textured finishes.

Each one-coat stucco system is a proprietary mix of Portland cement, polymers, fiber reinforcement and secret ingredients.  Each approved One-Coat-Stucco has its own Evaluation Report by the various Model Codes (the Model Codes have recently been merged into one Model code, ICC or IRC). Note:   The One-Coat-Stucco name is a misnomer since  there are actually at least two coats.

  •  A Moisture Barrier is required on top of moisture sensitive substrates such as wood, gypsum, etc.

  • One-Coat-Stucco is applied in coats with a total thickness of 3/8 to 1/2 inches - a brown or base coat and a finish coat.

  • Metal Accessories - Casing Beads or Stops or Grounds, Weep Screeds, Corner Aids, and Control Joints and Expansion joints at 144 square feet, window and door corners and per architectural details.

  • Flashings are required as part of weatherproofing the system.

  • Vulnerable to cracking.  Although, if mixed and installed properly, the proprietary mixes are very effective at minimizing cracking.

  • Details are typically well developed and part of the Evaluation Report or the Manufacturer's installation manuals.  See the Northwest Walls and Ceiling Bureau Stucco Resource Guide for further clarification.