This blog post is a compilation of three blog posts written by Reuben, which originally appeared at the moisture testing web site www.PrivateEyeMN.com.
Moisture testing on relatively newer stucco houses (mid 1980s - late 2000s) has become standard practice when buying a home in Minnesota, and a lot of those tests reveal problems with moisture intrusion. Water intrusion is never good news, but there are several options to consider when exploring a repair strategy for a home with water damage.
Remediation protocols range from retrofit, which consists of partial repair and maintenance, to full tear off and replacement, which consists of removing all of the stucco and replacing with an alternate cladding material, such as James Hardie HardiePlank® or LP Smartside®.
Today we'll be taking a closer look at all three repair strategies, all of which were performed by Sunset Construction Group (SunsetCG), a Minnesota company that specializes in repairing stucco houses with moisture intrusion problems.
When SunsetCG is contacted to perform stucco repairs on an existing home, there are four basic steps that take place; a review of the moisture testing report, removal of the stucco at the affected areas, repair of the affected areas, and maintenance on the rest of the stucco.
Case Study #1: Retrofit Repair
Review the Moisture Testing Report
The first thing SunsetCG wants to see is the moisture testing report, which is what we provide. This report will contain photos of the home along with moisture readings, which helps to determine the scope of the work and offers professional guidance to the buyer and sellers of a property. From there, a bid is put together on stucco repairs and various repair strategies are explored.
Reviewing this retrofit-level case study, we first performed moisture testing at this home in 2006, and found several areas with high moisture levels, but no repairs were conducted at that time. We performed moisture testing again in 2013, and many of those same areas showed high levels of moisture, so SunsetCG was contacted to perform repairs.
Here's an excerpt from our moisture testing report, showing exactly which areas of the wall sheathing had elevated moisture levels; our results from 2006 and 2013 are documented right next to each other on the report for comparison.
To keep this short, I'm only focusing on a small portion of the house.
Partial Stucco Removal
As you can see from the moisture testing report above, the big area of concern was directly below the first floor window. The next step was to have a minimal amount of stucco removed around the window, to expose and give access to the water damaged areas. Click the photo for a larger version.
After the stucco was removed, the source and severity of the moisture intrusion were confirmed. The sheathing, framing, and insulation of the impacted areas were repaired or replaced as needed. The impacted areas were then redesigned using improved materials and installation methods, to highly reduce the potential for future moisture problems.
Examples of new materials and methods would be new head flashing above the window and new pan flashing below the window.
The stucco color and texture were then patched and matched as closed as possible, and then the front of the house was painted with a high quality, breathable stucco paint to give the front of the house a uniform look.
While existing stucco homes may not have been constructed with the same details that a new stucco house would be built with today, the areas that have proven to perform over the years are maintained in their current condition with a quality caulk/seal effort. Some areas of particular attention will be the window miters, mullions and perimeter of windows, and vertical transitions between stucco and other surfaces, such as windows and doors.
The theory/risk proposition with a retrofit repair is that the areas that have performed over the past ten to fifteen years will probably continue to perform, even though it may not be an ideal installation. The main benefit with this type of repair is cost; these types of repairs will typically cost 30% - 40% of what a full tear off and redo would be.
When a retrofit repair is performed, a follow-up moisture testing inspection should take place three to five years after the repairs have taken place.
Along with the lower cost of repairs comes a limited warranty on the work. A ten year warranty (per MN State Statute) is not likely to apply under most (if not all) retrofit repair strategies, as the contractor is only touching part of a wall. If a ten year warranty is a must, the next two repair strategies would be good options.
Case Study #2: Wall-to-Wall Repair
The photos below show a house that had missing kickout flashing at a roof end, which led to extensive moisture damage at the front wall, including sheathing and minor framing repair.
After the stucco was removed and the damaged sheathing replaced, new plywood sheathing was installed, the window was properly flashed, and the first of two layers of building paper were applied to the exterior wall.
Proper kickout flashing gets installed at the roof end, and a quality drainage plane was installed to create an air gap.
The repaired areas are covered by a 10-year warranty, and the cost of the job was approximately $20k. Follow-up moisture testing can be conducted between three and five years after the repair work as a health check-up, as well as to provide documentation to any future home buyers that the repairs are performing as they should.
Case Study #3: Full Stucco Tear-off and Replacement
As is standard practice when buying a newer stucco home in Minnesota, the folks buying a stucco-clad home in Plymouth had invasive moisture testing performed as part of their purchase agreement. Despite the fact that there was no visible evidence of moisture damage inside or outside the home, the moisture testing report showed high levels of moisture in many locations throughout the home.
The home seller contacted SunsetCG to verify the results of the moisture testing, and the results were confirmed by cutting exploratory holes into the stucco; this helped to confirm the problem and determine the extent of the water damage.
Side note: If you ever happen to see a stucco home with caulked squares of stucco, you're probably looking at a home that has had exploratory holes cut. The photo below shows what these exploratory holes look like after they're patched.
After the home sellers were shown the extent of the moisture damage inside the walls, they decided to have the stucco completely torn off and the home resided with a different product. They decided to go with James Hardie® fiber cement siding, which has become a very popular product on new homes throughout Minnesota.
The photos below show the home before the stucco was torn off, while it was being repaired, as well as the finished product.
Benefits of a Full Tear-off and Redo
While a full tear-off and redo is the most expensive option when it comes to stucco repairs, there are plenty of benefits to this method. Instead of having only the areas with damage / water intrusion repaired, everything is opened up and redone. For example, pan flashing gets installed at all of the windows, proper kickout flashing gets installed at all of the roof ends, and the deck is completely re-flashed at the ledgerboard. At-grade or low wall plate lines that are too close to grade can be exposed and re-designed at the same time. All of the siding is now covered under a full 10-year warranty per MN Statute 327A, which can be a very attractive feature for potential home buyers. Finally, the stigma associated with newer stucco homes is removed.
For a full stucco tear-off and re-do, the cost can go into the six-figure realm, but of course this price involves all of the stuff that happens under the siding; it's not just about replacing existing siding. It's also about figuring out and repairing all of the items that caused water damage in the first place.
Special thanks to Matt Roach of SunsetCG for providing the photos and information about the repair process for these three case studies.
Author: Reuben Saltzman, Private Eye Moisture Testing