Where structural wood panels are used for sheathing, a minimum 1/8 inch separation shall be provided.A mist cure shall be maintained as needed for climatic conditions. Successive coats should be applied as soon as possible after the underlying coat has sufficient strength and rigidity to resist damage when the next coat is applied. The scratch coat must be scored horizontally on vertical surfaces. Scratch coat =3/8 inch thick, brown coat =3/8 inch thick, and finish coat =1/8 inch thick. Conventional stucco over wood should always be applied as a three-coat system.In addition, if the nails are to be trimmed flush and left in place, they need to be corrosion resistant as would be required for lath or other metal accessories, ASTM C 926 section 5.2 and C 1063 section 6. FBC 2510.3 Installation, references ASTM C 926 requires form ties or other obstructions (including masonry cut nails for clean out opening forms) to be removed or trimmed back even with the surface of the solid base.In lieu of a bonding agent, a dash coat, roughing the surface, or metal lath are also acceptable methods for bonding. When required by ASTM C 926, Section 5.2.2 an exterior bonding agent, conforming to ASTM C 932, shall be used on all masonry surfaces.Three-coat systems consist of: first coat = 1/4 inch thick, second coat = 1/4 inch thick, and finish coat = 1/8 inch thick over both masonry and cast concrete. Two-coat systems over masonry consist of: first coat = 3/8 inch thick and finish coat = 1/8 inch thick or over cast concrete consist of: first coat = 1/4 inch thick and finish coat = 1/8 inch thick. Conventional stucco over masonry surfaces may be applied with two or three coats.This document is meant to be used as a guide to address some of the common installation and proper application issues found during field inspections. This document is not all inclusive and does not cover all the requirements for compliant installation of stucco.

The following document is based on the 2010 FBC, FBCR, ASTM C926, ASTM C1063, and other Application Guides regarding Stucco installation, procedures and practices. Stucco Installation, Procedures and Guidelines Image Source: Kirk Giordano Plastering Inc.

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