![]() For surface irregularities, ACI 117 recognizes four surface classes from ACI 347R but expects the design professional to designate where each applies. Tolerances recommended by ACI 347R, and mandated by ACI 301, follow ACI 117 limits. "ACI 347R recommends limits for tolerances and surface irregularities in the completed concrete work. Among other topics, ACI 347R discusses issues such as the Contractor's design responsibility, loading information needed by the Contractor, submittals, and shoring responsibilities." "ACI 347R, Guide to Formwork for Concrete, recommends materials, applications, and specifications for concrete forming. The following is a partial quote from this support document. The source of my information in my previous posting is from AIA MasterSpec support Document for Section 033000_FL, August/September 2006 update. Thus ACI 347 should not be referenced in project specifications.ĪCI 117 is a standard that defines the various tolerances for concrete and reinforcing. I believe that ACI has moved the tolerances for concrete forms out of ACI 347R and into ACI 117.ĪCI's position is that ACI 347 is a Guide and it is not written in enforcable language. Quality of concrete forms under slab is also important. One of our condo clients uses USG Sheetrock Brand Lightweight Setting-Type Joint Compound (Easy Sand) in 1/8" thickness over USG Sheetrock Brand First-Coat Ready-mixed.Įasy Sand is available in a wide variety of setting times (8-360 minutes). The products used to "sack and patch" tilt-up buildings would be ideal. by BASF's Chemrex division -Thorocoat, it is 100% acrylic, breathable, and high-build, available in a varity of colors.but honestly in most PG's it gets VE'd and left natural, sealed with a penetrating water repellent if necessary, unless the surface is highly irregular, than once again an epoxy mortar (BASF's Emaco is a good product) works great as you can feather it down to 1/8" and work overhead - since its epoxy you do need proper ventilation.įor Concrete Balconies - depending on the irregularities in the surface, we specify the same coating (Torocoat - which also is available in a textured product), except we recommend that the Concrete forming specs include a requirement that on high rise work, new plywood forms be used every 5 floors, this will keep the underside looking less raggard. Well Robin you should not use any gypsum based or interior product in an open PG - we have had luck with a product manuf. ![]() It is the underslabs at a parking garage and also at balconies. If the concrete is irregular, we do specify an epoxy mortar to level the concrete - this is all based on an interior application, Robin did not say whether it was interior or exterior? Woncote made by Premix is another product. USG makes a product called Cover Coat (vinyl-based) that we use on many of our residential projects where the concrete slab is the finished ceiling. You can not use a gypsum compound on concrete as you will void the warranty from the joint compound manufacturer. ![]() It is best if you have also included some finish requirements for the formed concrete surface to eliminate major defects in the substrate. You can specify the same level of finish as on the gypsum board. You can also do it with a skim coat of gypsum board joint compound especially if you are trying to match adjacent gypsum board surfaces. How about one of the concrete repair product manufacturers? Euclid Chemical, Dayton Superior, Sika Corporation spring to mind immediately, but there are dozens of others who make specialty concrete coating products. Is there a specific product for application on the underside of concrete slabs to provide a smooth surface? Would you use a skim coat of plaster, or does someone manufacturer a product for this purpose? Thanks!īlock filler, or a fairly thick coating of a dry-fall paint. 4specs Discussion Forum: Skim coat at underside of concrete deck
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