To review concrete tolerances on a set, confirm which ACI 117 edition the specifications invoke and which of its mandatory and optional requirements the project designates, then find every place the drawings or other sections state a tolerance or assume one. Embeds, openings, slab surfaces, stairs, and cast-in-place surfaces that support precast, steel, facades, or elevators should cite one tolerance basis, and any tighter project tolerance should be stated in the specification, not only in a note. AI can flag conflicts; the design professional decides which tolerance governs.
What does ACI 117 cover?
ACI’s store page for ACI SPEC-117-10, Specification for Tolerances for Concrete Construction and Materials (ACI 117-10) and Commentary, reapproved 2015, says it provides standard tolerances for concrete construction and materials and is intended for specification writers and ACI committees as the reference document for establishing them. Its table of contents covers materials, including reinforcement fabrication and location and placement of embedded items (Section 2), foundations (Section 3), cast-in-place concrete for buildings, including formed openings, stairs, slope or plane, and sawcut depth in slabs-on-ground (Section 4), cast-in-place concrete at the interface with precast (Section 5), slipformed elements, mass concrete, canal linings, water-conveying tunnels and conduits, bridges, exterior pavements, chimneys and cooling towers, nonreinforced pipe, and tilt-up concrete (Sections 7 to 15). The masonry section has been removed. It ends with notes to the specifier and mandatory and optional requirements checklists.
The ACI store lists ACI SPEC-117-10 with a publication year of 2010, reapproved 2015, as a protected PDF, and relates it to ACI PRC-117.1-14, Guide for Tolerance Compatibility in Concrete Construction, which ACI describes as a guide for mitigating tolerance conflicts at embedded items, elevator cores, slab and wall openings, cladding and infill wall systems, finish floor coverings, and expansion joints. ACI’s upcoming standards page listed no draft for public discussion. Checked October 27, 2026. ACI 117 applies only where the contract documents invoke it, directly in a project specification or through another reference specification the project cites, so record the edition each document names.
The ACI 301 guide covers ACI’s general concrete construction specification and its checklists; this page follows the tolerances themselves and the trades that depend on them. Structural steel erection tolerances and the interface with steel follow the AISC 360 guide and the structural steel specifications guide, and mass timber bearing on concrete follows the mass timber tolerances guide.
Gather every document that states or assumes a concrete tolerance
Collect the cast-in-place concrete specification and its references article, the concrete finishing and floor flatness requirements, the structural general notes, foundation, slab, and wall plans, embed plate and anchor rod details, slab edge and opening details, stair sections, and the sections that attach to concrete: structural steel, precast, curtain wall and cladding, elevators, and resilient or wood flooring.
Add the ACI 117 and ACI 301 editions the specifications cite, including the notes to specifier and checklists, from copies you are licensed to upload, and the facade, elevator, and precast product data or delegated design submittals once they arrive.
Trace each tolerance from the specification to the trade that depends on it
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Edition and checklists | Concrete specification, references article, ACI 301 citation, general notes | Record the ACI 117 edition each document cites and which mandatory and optional checklist items the specification designates. |
| Embedded items and anchors | Embed and anchor rod details, steel and facade specifications, general notes | Confirm the tolerance assumed by the steel, facade, or equipment attachment is stated, and flag details that ask for a tighter placement than the cited concrete tolerance without a project requirement. |
| Openings and slab edges | Slab edge plans, opening details, curtain wall and elevator drawings | Check that slab edge, shaft, and opening tolerances the facade and elevator documents assume match the concrete specification or are called out as project requirements. |
| Slab surfaces and finishes | Concrete finishing article, floor finish schedule, flooring specifications | Confirm the slab surface tolerance and how it is measured are stated once, and that flooring sections do not require flatness the concrete specification never asks for. |
| Precast and tilt-up interfaces | Precast and tilt-up specifications, bearing details, foundation plans | Check that cast-in-place bearing surfaces and anchors supporting precast or tilt-up cite the interface tolerance, and that the precast section does not cite a different basis. |
| Stairs and elevations | Stair sections, architectural finish elevations, structural slab elevations | Flag stair and floor elevation notes whose stated tolerance conflicts with the cited concrete tolerance or with the finish build-up drawn. |
The concrete sections themselves continue in the concrete specifications guide, curtain wall anchors in the curtain wall specifications guide, elevator hoistways in the elevator specifications guide, and flooring in the resilient flooring guide.
Example: curtain wall embeds that assume a tighter tolerance than the concrete specification
Hypothetical example. A twelve-story concrete office building has a unitized curtain wall anchored to cast-in embeds at each slab edge. The concrete specification cites ACI 117 without designating any optional requirements, the curtain wall specification assumes a slab edge and embed location tolerance tighter than the concrete specification states, the embed detail carries a placement note that matches neither, and the resilient flooring section requires a floor flatness that the concrete finishing article does not specify.
The curtain wall specification assumes slab edge and embed tolerances tighter than the concrete specification states, the embed detail note matches neither section, and the flooring section requires a flatness the concrete finishing article does not specify. Confirm which tolerance governs at the slab edges and floors, and coordinate the concrete, curtain wall, and flooring specifications with the embed detail.
The architect and engineer of record decide whether to tighten the concrete tolerance as a project requirement or to provide adjustability in the curtain wall anchors, and align the flooring and finishing requirements. The finding is a conflict between documents, not a measurement of the built concrete.
Review concrete tolerances with Groundbook
Upload the current drawings and specifications to Groundbook, and state the edition, amendments, and review scope in your instructions. Add the ACI 117 and ACI 301 editions the specifications cite, including the checklists, from copies you are licensed to use where the license permits uploading them, along with the adopted code and amendments. See how Groundbook works with local and licensed codes.
Compare the cast-in-place concrete and finishing specifications, the structural general notes, foundation, slab, and wall plans, embed and anchor rod details, slab edge and opening details, stair sections, and the structural steel, precast, curtain wall, elevator, and flooring specifications. Flag ACI 117 editions that differ between documents, checklist items designated nowhere, tolerances assumed by attaching trades that are tighter than the cited concrete tolerance without a project requirement, slab surface requirements that differ between sections, interface tolerances for precast or tilt-up with no basis, and stair or elevation tolerances that conflict. Use the supplied ACI 117 and cite both sources.
Groundbook links each potential finding to the sheets, details, and specification articles involved. It does not measure as-built concrete, compute tolerance stack-ups, or design adjustable connections.
Document review does not accept or reject concrete work, and it does not replace the design professional, the surveyor, or the testing agency.