Reference
Stucco Glossary & Definitions
Plain-English definitions for every stucco term, written by licensed contractors with 500+ completed projects.
What is Weep Screed?
A metal flashing installed at the base of a stucco wall where it meets the foundation. Weep screeds provide a drainage path for moisture that gets behind the stucco, preventing water from becoming trapped and causing rot or mold. Corroded or improperly installed weep screeds are the #1 cause of stucco water damage in Southern California.
Weep Screed Repair →What is Stucco Delamination?
When stucco separates from the underlying surface (lath, sheathing, or a previous stucco layer), creating hollow areas or bulges. Delamination is caused by moisture intrusion, improper bonding during application, or freeze-thaw cycling. You can detect it by tapping the wall — delaminated areas sound hollow.
Stucco Repair →What is EIFS (Exterior Insulation and Finish System)?
A synthetic stucco system that uses foam insulation boards covered with a thin acrylic finish coat. Unlike traditional (hard coat) stucco, EIFS is lighter and provides insulation but is more vulnerable to moisture intrusion if not properly installed with drainage channels. Also called synthetic stucco or Dryvit.
What is Scratch Coat?
The first layer of traditional three-coat stucco, applied directly to the metal lath. The scratch coat is scored with horizontal grooves ("scratched") while wet to create a rough surface for the next layer to bond to. It is typically 3/8 inch thick and made of Portland cement, sand, and water.
What is Brown Coat?
The second layer of traditional three-coat stucco, applied over the scratch coat. The brown coat provides a smooth, level surface for the finish coat and is typically 3/8 inch thick. It must cure for at least 7 days before the finish coat is applied.
What is Finish Coat?
The final visible layer of stucco that provides color and texture. Finish coats can be smooth, sand, dash, lace, or custom textures. This is the layer you see from the street. Modern acrylic finish coats offer better color retention and flexibility than traditional cement-based finishes.
Smooth Stucco Finishes →What is Fog Coat?
A thin, sprayed-on layer of cement and pigment used to refresh the color of existing stucco without adding a full new coat. Fog coating is the most affordable way to change stucco color but only works on cement-based stucco in good condition. It does not repair cracks or structural damage.
What is Lath (Metal Lath / Wire Lath)?
A sheet of expanded metal mesh nailed to the wall sheathing before stucco is applied. Lath provides a surface for the stucco to grip and adds structural reinforcement. Properly installed lath includes weep screed at the bottom and control joints at intervals to manage cracking.
What is Control Joint?
A pre-formed groove or metal strip installed in stucco walls to control where cracking occurs. Control joints allow the stucco to expand and contract with temperature changes without developing random cracks. They should be placed every 144 square feet or at natural stress points like window corners.
What is Efflorescence?
White, powdery deposits that appear on the surface of stucco. Efflorescence occurs when water migrates through the stucco and dissolves salts in the cement, which then crystallize on the surface as the water evaporates. It indicates moisture is moving through the wall and may signal a drainage problem.
Stucco Repair →What is Re-Stucco?
The process of removing existing stucco down to the sheathing and applying entirely new stucco from scratch — new lath, scratch coat, brown coat, and finish coat. Re-stucco is recommended when damage exceeds 30% of the exterior, when you want to change the finish style, or when the underlying structure needs remediation.
Re-Stucco Services →What is Stucco Patching?
Repairing a localized area of damaged stucco by cutting out the damaged section and applying new stucco material to match the surrounding texture and color. Quality patching is invisible — the repaired area should be indistinguishable from the original wall.
Stucco Repair →What is Three-Coat Stucco (Hard Coat)?
Traditional stucco application consisting of three layers: scratch coat, brown coat, and finish coat, applied over metal lath. Three-coat stucco is approximately 7/8 inch thick and is the standard for residential construction in Southern California. It is more durable than one-coat or EIFS systems.
What is One-Coat Stucco?
A stucco system using a single thick application of fiberglass-reinforced cement over foam sheathing, finished with an acrylic color coat. One-coat stucco is faster to install but thinner than three-coat, making it more susceptible to impact damage and cracking.
What is Thermal Cycling?
The repeated expansion and contraction of stucco caused by daily temperature swings. In Southern California, exterior surfaces can reach 150°F in direct sun and drop to 50°F overnight. This constant movement creates stress fractures over time, especially around windows, corners, and control joints.
What is Moisture Intrusion?
Water penetrating behind the stucco membrane through cracks, failed caulking, improper flashing, or corroded weep screeds. Moisture intrusion is the most destructive stucco problem because it causes hidden rot, mold growth, and structural damage that isn't visible from the outside until significant deterioration has occurred.
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