Residential Mixed-Use Building: 417 Issues Found
An anonymized residential mixed-use building project uncovered 417 issues—including 110 critical violations affecting structural coordination, fire protection, ceiling heights, and mechanical systems—before construction began.
Issues by Discipline
Critical Issues Found
Water Heater WH3 Fuel Type Conflict: Equipment Note Says ELECTRIC but Specification States GAS-FIRED
CriticalCategory: Plumbing
On the same detail drawing (WH3 Piping Detail), Equipment Note 7 identifies the water heater as 'ELECTRIC WATER HEATER' while the narrative specification states 'WATER HEATERS (2) SHALL BE HIGH EFFICIENCY, GAS-FIRED, STORAGE TYPE.' The Water Heater Schedule on P901 confirms WH3 is ELECTRIC with 18 KW input at 208/3/60.
Why it matters: Conflicting fuel type specifications create ambiguity that could result in incorrect equipment procurement and installation. Gas-fired and electric water heaters require completely different infrastructure (gas lines vs. electrical circuits), potentially causing costly rework and delays.
Suggested next step: Reconcile the fuel type specification. Verify whether WH3 should be electric or gas-fired, and update both the detail drawing and specification to consistently specify the correct fuel type and associated infrastructure requirements.
Steel Lintel ML1 and ML2 Sizes Conflict Between S002 Schedule and S104 Notes
CriticalCategory: Structural
Sheet S002 Steel Lintel Schedule shows ML1 as W8x24 and ML2 as HSS16x8x1/2. However, Note 11 on sheet S104 defines ML1 as (2) 6x3 1/2x5/16 (LLV) and ML2 as W16x40 LINTEL. These are completely different steel member types - double angles versus wide flange for ML1, and hollow structural section versus wide flange for ML2.
Why it matters: Conflicting structural member specifications create ambiguity that could result in incorrect material procurement and installation. Different member types have vastly different load-carrying capacities and connection requirements, potentially causing structural failure or costly rework.
Suggested next step: Reconcile the steel lintel specifications. Verify the correct member sizes and types based on structural analysis, and update both the schedule and plan notes to consistently specify the same members.
Roof Hatch Fire Rating Conflict: 2-HR Rating Required vs Non-Rated BILCO L-50-TB Specified
CriticalCode Reference: 2021 International Building Code
Category: Fire Protection
Sheet A601 Section 11 (ST-2 SECTION @ ROOF) specifies a '2-HR RATED ROOF HATCH' and explicitly refers to Detail 8/A106 for roof hatch details. However, Detail 8 on sheet A106 specifies 'BILCO L-50-TB ENHANCED PERFORMANCE' as the basis of design. The BILCO L-50-TB is a thermally broken roof hatch but is NOT a fire-rated product and cannot provide a 2-hour fire rating.
Why it matters: A non-rated roof hatch in a location requiring 2-hour fire rating creates a breach in the fire separation, allowing fire and smoke to spread. This violates code requirements and creates a life safety hazard.
Suggested next step: Either update Detail 8 to specify a fire-rated roof hatch that achieves 2-hour rating, or revise the fire rating requirement if a non-rated hatch is acceptable per code analysis. Ensure the specified product matches the required rating.
Stair Doors ST1-2 and ST2-2 Require 3-Hour Fire Rating but Door Type 7 Uses GL-5 Glazing Rated for Only 90 Minutes
CriticalCode Reference: 2021 International Building Code
Category: Fire Protection
The door schedule shows stair doors ST1-2 and ST2-2 (Second Floor) as Door Type 7 with a 3-hour fire rating requirement. However, the Door Type 7 elevation specifies GL-5 glazing, which per the Glazing Types legend is only rated for 90 minutes. This creates an incompatible assembly where the glazing fire rating (90 minutes) cannot achieve the required door assembly fire rating (3 hours).
Why it matters: Incompatible fire ratings between door assembly and glazing create a breach in the fire separation. The glazing will fail before the required 3-hour rating is achieved, compromising the stair enclosure's fire protection and creating a life safety hazard.
Suggested next step: Either update Door Type 7 to use glazing rated for 3 hours, or revise the door fire rating requirement to match the glazing rating. Ensure all components of the door assembly meet the required fire rating.
Smoke Barrier Assembly W605-SB Lacks Required 1-Hour Fire-Resistance Rating
CriticalCode Reference: 2021 International Building Code
Category: Fire Protection
The drawing shows wall assembly W605-SB explicitly labeled as '(SMOKE BARRIER)' but this assembly is based on the W405/W605 construction which is labeled 'NON-RATED'. The W605-SB shows only '5 1/2" WD FRMG' as its defining characteristic, with the base W405 assembly consisting of 5/8" GWB on both sides of 3 1/2" wood framing. IBC Section 709.3 requires smoke barriers to have a 1-hour fire-resistance rating.
Why it matters: A non-rated smoke barrier fails to provide the required fire separation, allowing fire and smoke to spread between areas. This violates code requirements and creates a life safety hazard during fire events.
Suggested next step: Update wall assembly W605-SB to achieve 1-hour fire-resistance rating per IBC 709.3. This may require additional layers of Type X GWB or alternative construction methods to meet the rating requirement.
Lobby (Room 103) Ceiling Height of 6'-3" is Below Minimum Required 7'-6"
CriticalCode Reference: 2021 International Building Code
Category: Architectural
Building Section 1 shows 'LOBBY 6'-3"' indicating a ceiling height of 6 feet 3 inches (75 inches) for the lobby space (Room 103) at the ground level. This is 15 inches less than the minimum ceiling height required by code. The lobby is an occupiable space and serves as part of the building's means of egress, both of which require minimum 7'-6" ceiling height.
Why it matters: Insufficient ceiling height violates code requirements for occupiable spaces and means of egress, potentially creating accessibility issues and code violations. The lobby serves as a critical egress path requiring adequate headroom.
Suggested next step: Increase lobby ceiling height to minimum 7'-6" per IBC requirements. Verify structural clearances and coordinate with MEP systems to ensure adequate space is available.
RCP Note 1 Specifies 7'-0" Minimum Ceiling Height for Means of Egress and Corridors Where 7'-6" is Required
CriticalCode Reference: 2021 International Building Code
Category: Architectural
RCP Note 1 explicitly states the minimum ceiling height shall be 7'-0" for means of egress paths, corridors, occupiable spaces, and habitable spaces. However, IBC Section 1003.2 requires means of egress to have a ceiling height of not less than 7 feet 6 inches, and Section 1208.2 requires occupiable spaces, habitable spaces, and corridors to have a ceiling height of not less than 7 feet 6 inches.
Why it matters: Incorrect minimum ceiling height specification could result in construction that violates code requirements, potentially requiring costly corrections or permit rejection. Means of egress and corridors require adequate headroom for safe passage.
Suggested next step: Update RCP Note 1 to require minimum 7'-6" ceiling height for means of egress, corridors, occupiable spaces, and habitable spaces per IBC 1003.2 and 1208.2.
Conflicting International Building Code Years: 2015 vs 2021
CriticalCategory: Code Compliance
Multiple versions of the International Building Code are referenced in this document. Found references to year(s) 2015 alongside 2021. The 2021 International Building Code (2021) was selected as the applicable code since it is the latest edition, but older version(s) are still referenced on some sheets.
Why it matters: IBC 2015 and 2021 have different requirements for structural design, fire protection, accessibility, and other critical building systems. Mixing code editions creates design inconsistencies and potential code violations.
Suggested next step: Update all references to 2021 IBC consistently throughout the document set. Remove all references to 2015 IBC and verify all design requirements meet 2021 code standards.
Project Context
This residential mixed-use building project involved multiple stories with dwelling units, commercial spaces, and parking, requiring careful coordination between architectural, structural, mechanical, and fire protection systems.
The AI review identified critical coordination issues including conflicting structural member specifications between schedules and plan notes, incompatible fire ratings between door assemblies and glazing, and missing fire-resistance ratings for smoke barriers. Multiple document coordination errors were found, with conflicting specifications between drawings and schedules.
Code compliance issues included incorrect minimum ceiling height specifications, outdated code references, and insufficient structural details. Mechanical system issues included missing return air paths and contradictory HVAC system strategies between different drawing sheets.
Key Challenges
- Multi-story building requiring proper fire separation and means of egress
- Complex structural system with multiple lintel types and foundation systems
- Coordination between architectural, structural, and MEP disciplines
- Conflicting specifications between drawings, schedules, and details
- Fire protection requirements for stair enclosures and smoke barriers
- Mechanical system design and return air path requirements
Impact of Finding These Issues Early
Prevented Structural Failures
Critical issues like conflicting structural member specifications, insufficient lap splice lengths, and contradictory foundation systems would have resulted in incorrect material procurement and potential structural failures. Finding these before construction prevented costly rework and safety hazards.
Avoided Fire Protection Violations
Incompatible fire ratings between door assemblies and glazing, non-rated smoke barriers, and incorrect roof hatch specifications would have created breaches in fire separation, violating code requirements and creating life safety hazards.
Prevented Code Violations
Multiple code violations including insufficient ceiling heights, incorrect minimum height specifications, and outdated code references would have resulted in permit rejection, stop-work orders, or costly corrections during construction.
Resolved Document Coordination Errors
Over 400 issues including conflicting specifications between drawings and schedules, contradictory system types, and missing details would have created confusion and rework during construction, significantly impacting project schedule and budget.
This is an anonymized example. Findings shown are excerpts for illustration. Actual project details have been modified to protect client confidentiality.
One issue found pays for the whole check