Skim Coat of Plaster or Stucco

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Author Message Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1542 Registered: 05-2003 Posted on Wednesday, January 06, 2016 - 05:11 pm:    Can someone provide a definition for skim coat, please? George A. Everding, FCSI, CCS, CCCA, AIA Senior Member Username: geverding Post Number: 817 Registered: 11-2004 Posted on Wednesday, January 06, 2016 - 05:29 pm:    Here is the GA-214-07 definition: "Either a thin coat of joint compound trowel applied, or a material manufactured especially for this purpose and applied in accordance with manufacturer’s recommendations, over the entire surface." The document discusses skim coats for Level 5 finishes in some detail. (Note that GA-214 has been updated since the 2007 version quoted; the current version is available on the Gypsum Association website) George A. Everding, FCSI, CCS, CCCA, AIA Senior Member Username: geverding Post Number: 818 Registered: 11-2004 Posted on Wednesday, January 06, 2016 - 06:37 pm:    Sorry. I missed your topic title referring to plaster, not gypsum. Here is the TSIB definition from the Plaster Manual: SKIM COAT: a coat of material, base coat or finish material, applied to improve, “smooth out” or level a surface. A stucco finish coat applied directly to masonry or concrete. See tsib.org Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 1543 Registered: 05-2003 Posted on Wednesday, January 06, 2016 - 07:09 pm:    Thanks George, I forgot about TSIB, an excellent reference, ASTM C 926 definition was not working for me: "3.2.9.9 skim coat—a thin finish coat applied to an existing plaster surface or other substrate to improve appearance." My client was confused, she thought the skim coat was part of the standard number of coats for stucco application over a solid substrate.