Weep Screed Buried by a Raised Patio
A 2009 two-story wood-frame house has three-coat stucco over Grade D building paper and metal lath. The rear wall meets a paver patio that the homeowner added two years ago. The patio surface now sits about 3 inches above the adjacent soil and covers the original weep screed; no weep screed, weep holes, or base flashing are visible at the stucco-to-patio joint. Dark staining and white efflorescence extend 8 to 10 inches up the stucco in two bays. A 3/8-inch horizontal crack runs about 6 feet along the wall 5 inches above the pavers. A pin-type moisture meter reads 22 to 28 percent at the base and 12 to 14 percent at 4 feet. The interior is finished and shows no stains. The homeowner wants to know whether sealing the crack and repainting will be enough.
1. What is the most likely primary defect, and how does the raised patio change the wall's drying and drainage path? Explain the mechanism rather than naming a product.
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The key defect is not the crack by itself; it is the loss of the base-of-wall drainage and drying detail. A weep screed is supposed to sit above grade and above the patio or roof surface so water that enters the stucco can escape at the bottom and the stucco can terminate above a drainage path. Raising the patio 3 inches over the original soil line buries that termination and creates a horizontal reservoir against the wall. Stucco is a reservoir cladding: it can absorb and store water, and water will wick upward and inward through the paper, lath, and sheathing. The efflorescence and elevated readings at the base are consistent with prolonged wetting. The 3/8-inch crack is a symptom and may also admit water, but sealing it does not restore drainage. Because the wall is wood-framed, the hidden risk is sill plate and sheathing decay or corrosion, not just stained paint.
2. What inspection steps would you take before writing the report, and what would you look for at the base and behind the finish?
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I would map moisture readings vertically and horizontally, then expose the base. That means removing a small section of stucco or the patio edge to see whether a weep screed exists, whether it is clear, and how far the stucco and paper extend below the patio. I would check for a sill plate, sheathing, and framing at the base, and look for rusted fasteners, soft wood, or delaminated paper. I would also check the interior side and the adjacent soil grade. Exploratory openings should be made by a qualified stucco contractor with the owner's permission and repaired afterward. The report should state the readings, the exact clearances observed, and the limits of a visual and moisture-meter survey. It should not claim hidden damage is absent just because the interior is dry.
3. The owner proposes sealing the crack and repainting. How should you respond, and what report language is defensible?
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I would tell the owner that sealing the crack and repainting is a cosmetic repair, not a correction of the water-management defect. Sealing over a wet substrate can trap moisture and make the damage less visible. The defensible recommendation is to restore the required clearance and drainage at the base, correct the patio-to-wall detail, and evaluate any hidden decay before cosmetic work. The report should identify the buried weep screed or missing base termination as a defect, describe the moisture readings and staining, and recommend evaluation and repair by a qualified stucco contractor. I would avoid predicting the exact extent of damage, but I would not describe the wall as serviceable based only on a dry interior.