Stucco Position Paper

Q. We have heard there are some stucco problems but not much more. What exactly are the problems?

A. The problems we have seen are associated with moisture either from the interior or exterior being trapped in the wall cavity creating mold and rotting the sheathing and framing members. Sometimes the mold is so extensive it creates indoor air quality problems with potential health problems. These problems are mostly on stucco houses built in the late 1980s and later.

Q. How widespread is the problem?

A. This is an industry-wide problem. It is not just in the Midwest, Minnesota or Woodbury. It has come to our attention in Woodbury because there were many homes built here in the past 10 years.

Q. What are the signs to look for to determine if my home has a problem?

A. On the interior, if the bottoms of windows are discolored or the base trim is warped or carpet is wet, these are indications of a leak. If there is a moldy smell in the house, there may be leaks into the wall cavities that may not show other signs of leakage. On the exterior, if there are brown streaks below the corners of windows or where window units are joined, it is likely there is a leak at that location. Intersections of walls and roofs are also susceptible to leaks, which will be indicated by brown streaks.

Q. What causes the problems?

A. Window leaks are the cause of the majority of the damage but the causes may be many, including:

  • The paper around windows and other openings was installed incorrectly.
  • Head flashing was not used on windows (windows with flanges were thought to be self-flashed).
  • One layer of paper was used. Water may be leaking through the paper.
  • The windows themselves leak.
  • Kickout flashing was not installed at the wall/roof intersections where the roofline does not extend below the wall.
  • The deck ledger board was not flashed.
  • Moisture from rain during construction or wet building materials remain in the wall (construction moisture).
  • Interior moisture is permeating into the wall.
  • Lack of drying capacity. All walls will likely leak sometime during their life. In addition condensation and construction moisture will be in the walls. Stucco walls are very tight and cannot withstand much moisture without creating mold and rot.
  • Solar drive may be pushing moisture from a wet stucco wall into the wall cavity.
  • Type 15 felt may be acting as a vapor retarder trapping moisture in the wall.
  • Oriented strand board (OSB) sheathing has a low perm rating and it may be acting as a vapor retarder creating a double vapor retarder situation. In addition OSB absorbs and retains moisture making it vulnerable to mold and rot.
  • The staples that stick through the sheathing are collecting frost or condensation and dripping within the wall cavity.
  • The high number of staples used to fasten the lath creates many penetrations that could both leak and condense moisture.
  • The staples were driven into the lath with excessive force causing the lath to cut the paper creating a leak.
  • Wind driven water is getting on the wall through the soffit vents and running down the wall between the sheathing and the paper.
  • Weep screeds were not used at the bottom of the stucco. This may prevent trapped water from draining.
  • Stucco was installed below ground. This may prevent trapped water from draining or may wick water up to the framing. In addition, when stucco is applied below grade there is no clear definition of where grade should be and often the grade is placed against the wood framing causing a guaranteed rot situation.
  • Stucco is installed directly on the foundation without paper or a weep screed. This prevents trapped water from draining.
  • Landscape trees or bushes that contact the stucco create an area that introduces and holds moisture in the stucco. The moisture permeates into the wall.

Q. Stucco historically has been used for more than 100 years without problems. Why are we having problems now?

A. This is perhaps the most important question and one that we can only speculate on the possible causes, but cannot give a definitive answer. We do know that houses are being built with tighter wall cavities and when the cavity gets wet it dries out very slowly. Older houses had more air circulation in the wall that allowed the cavities to dry out. There is also speculation that wood windows in the older houses swelled when they were wet creating a seal between the stucco and the wood, effectively sealing out the water. New windows are typically vinyl or steel and do not swell and create a seal.

Q. My house doesn't have stucco. Are there other types of siding that I should be concerned about?

A. Woodbury has documented the conditions found in over 300 non-stucco homes resided in the last two years. Serious failures were found in less than one percent of the cases. We do not feel we can draw any conclusions so far based on these limited data. We would suggest that home owners regularly maintain the caulking around windows and other openings in the walls. You may also want to consider moisture testing, especially if your home is nearing the end of its warranty period.

Q. What is Woodbury doing about this problem?

A. The Woodbury Building Inspection Division has been very proactive since discovering the problem in the spring of 1999. Research was done to identify the problems and possible causes. In May 1999, the City of Woodbury hosted a fact-finding meeting with stucco contractors, general contractors, municipal building inspectors, industry representatives and other interested parties. Ron Glubka, Chief Building Official, attended a similar meeting hosted by the State of Minnesota Building Codes and Standards Division. The city identified possible causes and solutions. A stucco inspection checklist was created and a mandatory stucco inspection became part of the inspection process for all houses with stucco. The May 1999 City of Woodbury Building Inspection Newsletter, sent out to almost 1,000 contractors, detailed the new inspection requirements and code requirements. Now each new house built with stucco undergoes an inspection of the critical areas of stucco application. The City of Woodbury continues to gather information. If further research indicates additional changes need to be made in construction techniques or inspections, the City of Woodbury will take whatever action is appropriate.

Q. What should be done if there are signs of leaks on our house?

A. There are a number of steps that can be taken or places to call for help. Be sure to keep detailed, written records of your contacts with contractors, insurance companies, and inspectors.

  • Arrange for a moisture test with a private home inspector. Information on moisture testing is detailed below.
  • If a moisture problem is found, contact your builder to make a claim for repairs. The contractor shall warranty the house for one year against defects and ten years against structural defects. Some builders may provide additional warranties.
  • Contact your builder's insurance company to make a claim.
  • The State Commerce Department, (651) 296-2488, may provide assistance with contractors or provide information on the availability of the state builder's recovery fund. They can also provide the builder's insurance and contact information.
  • The State of Minnesota Building Codes and Standards Division has been helpful to several home owners with stucco problems. Contact (651) 296-4639.
  • Contact your insurance company to see if it covers moisture damage.
  • Licensed Contractors can make necessary repairs.
  • The City of Woodbury has a Warranty Information Brochure that explains various methods available to have warranty work completed. Contact the Building Inspection Division at (651) 714-3543. 

Q. I own a stucco home, and I don't see any symptoms of leaks right now.

A. Most of the problems we have seen are caused from leaks around windows. Caulking the sides and bottom of the window will help prevent water infiltration. There are different schools of thought on caulking the top of the windows. One is to caulk the top of the window to prevent water from getting in and the other is to not caulk the top so water that is behind the stucco but on the tarpaper can get out. A moderate position is to caulk the top of the window but leave some small openings in the caulk to let any water that may be on the tarpaper out. Additional openings and penetrations such as doors and vents should also be caulked.

Q. How can I arrange for a moisture test?

A. Whether to test is up to the home owner. There are a variety of tests that private inspectors may use. They range from passive tests that use instruments to take relative moisture readings in non-conductive solid materials such as wood and masonry, to intrusive tests where openings are made to allow a probe inside the wall cavity to measure moisture. These tests may be helpful in providing information that may indicate whether there is a moisture problem. The only way to be certain, however, is to remove either the sheetrock on the interior or the stucco on the exterior of the home. Private home inspectors that specialize in moisture detection can be found in the yellow pages under "Home & Building Inspection" and "Inspection Service." Inspectors who have worked in Woodbury in the recent past on stucco issues include:

Acuity Engineers, Inc., (651) 222-7975 Klemmensen, Dave, (651) 731-8750
Air Tamarack, Inc., (651) 696-0267 Klossner, Steve, (651) 436-5120
Built Environments Inc., (651) 330-9329 Private Eye Home Eval. Svc., (651) 639-0184
CMT-Certified Moisture Testing, (651) 257-7310 Prof. Engineering Consultants, (651) 490-9266
Guy Engineering Corp., (952) 933-6161

The City provides this list of inspectors solely as a service to aid interested citizens. In listing these inspectors that have recently worked in the city the City is not making a recommendation in favor of these individuals and in no way warrants or endorses the quality of their work.

In choosing any contractor, it is always helpful to ask for and check references from recent work that is similar to what you need done. You can also check with organizations that may provide information on the contractor's business practices (i.e., the Better Business Bureau or any licensing authority the contractor works under). Always maintain a complete paper file of all transactions, conversations and reports, including dates and names.

Q. If there is a problem with the stucco on my home, what will be required to correct it?

A. A building permit is required for stucco repairs. The building code requires that all wood with mold or rot be removed and repaired. Areas that do not show signs of leaks, mold, rot or deterioration may remain.

Q. Who do I contact to repair my stucco?

A. Your insurance company may recommend a contractor to perform the repair work on your stucco home.

In choosing any contractor, it is always helpful to ask for and check references from recent work that is similar to what you need done. You can also check with organizations that may provide information on the contractor's business practices (i.e., the Better Business Bureau or any licensing authority the contractor works under). Always maintain a complete paper file of all transactions, conversations and reports, including dates and names.

Q. Does all the stucco on my home need to be removed if there is a moisture problem present?

A. The building code only requires that all wood with mold or rot be removed and repaired. Areas that do not show signs of leaks, mold, rot or deterioration may remain. You may choose to pay to have it all removed, but it is not required by code.

Q. Once my stucco has been repaired, it is safe to put stucco back on the exterior of my home?

A. The exterior you choose for your home is up to you. Because of the reasons cited above, we cannot recommend stucco exteriors at this time. Many home owners repairing their stucco homes are choosing an alternate siding. The most popular choice seems to be one of several fiber cement board siding products. Manufacturers include James Hardie Building Products, Certainteed Corporation, and Cemplank. Information about these products are available from building supply stores, siding contractors and the manufacturers' websites.

Q. Will my home owner warranty cover damage due to moisture?

A. Minnesota Statute §327A.02 requires new homebuilders to provide certain warranties: that the home will be free from defects caused by faulty workmanship and defective materials due to noncompliance with building standards during the one (1) year period following completion of the home; that the home will be free of defects caused by faulty installation of plumbing, electrical, heating and cooling systems during the two (2) year period following completion of the home; and that the home will be free from major construction defects during the ten (10) year period following completion of the home. If moisture is caused by any of theses defects, the moisture damage will be covered by the warranty if you timely notify your homebuilder in writing and if you timely file a claim. You should also check to see if the homebuilder has provided a warranty program that is broader that the statutory warranties, as this may embody additional protections or impose additional requirements on you.

Q. Will I need to involve an attorney?

A. If your builder fails to make repairs and honor the warranty, it way be necessary to involve an attorney. Furthermore, the time limits for notifying your homebuilder or for commencing a claim against your homebuilder must be strictly complied with or your warranty claim can be barred. Minnesota Statute §327A.03 (a) requires you to notify your homebuilder in writing of any loss or damage within six (6) months after you discovered or should have discovered any loss or damage. Furthermore, Minnesota Statute §541.051 requires you to bring suit on a claim of a construction defect within two (2) years of discovery of the defect and within ten (10) years of substantial completion of the house. In addition, a recent case (Westin v. McWilliams & Associates, Inc., 694 N.W.2d 558|Minn.Ct.Apps. 2005|), held that the statute of repose is stated as ten-year time period when an action can "accrue" and further states that a suit can be brought within two years after the tenth year. More practically, when a contribution and indemnity claim accrues in fact after the specified ten-year period, the statute deems the accrual to occur at the tenth anniversary, and suit can be brought on such a claim in years eleven and twelve. Also, many homebuilders require home owners to sign arbitration agreements. If so, those agreements must be compiled with in submitting a claim. An attorney can advise you about your rights regarding warranty items, inform you of legal limitations of warranties, the deadlines for commencement of any legal action regarding the damages, and represent you in reaching a settlement in any legal action you may need to take. You should consult with an attorney if you have questions about your need for legal representation.

Q. Where can I go to get more information on this subject?

A. Contact the building inspection department in your city. Internet searches using keywords and strings such as "stucco," "moisture damage," "stucco and moisture problems," "moisture in buildings " and "mold in home" can also provide more background information on the subject.