Residential Rowhomes: 370 Issues Found
An anonymized residential rowhomes project uncovered 370 issues—including 119 critical violations affecting carbon monoxide detection, fire protection, water efficiency, seismic design, and outdated code references—before permit approval.
Issues by Discipline
Critical Issues Found
Missing Carbon Monoxide Detection for Building with Attached Garages
CriticalCode Reference: 2024 International Building Code
Category: Fire Protection
The electrical layout shows a building with attached garages on the first floor (indicated by ceiling outlets for overhead door openers) and dwelling units on the second floor. The legend explicitly lists all electrical device types including smoke detectors but does not include any carbon monoxide detector or alarm symbols. Per Section 915.1.1(3), buildings with attached private garages require CO detection, and per Section 915.2.1, CO detection must be installed in dwelling units outside of each separate sleeping area in the immediate vicinity of the bedrooms.
Why it matters: Missing carbon monoxide detection creates a life safety hazard. CO is an odorless, colorless gas that can cause death. Buildings with attached garages are at increased risk of CO infiltration from vehicle exhaust, making detection systems critical for occupant safety.
Suggested next step: Add carbon monoxide detection/alarms to the electrical plans. Install CO alarms outside each separate sleeping area in the immediate vicinity of bedrooms per IBC 915.2.1. Update electrical legend to include CO detection symbols.
Garage Appliance Pilot/Burner Height Incorrectly Stated as Floor Level Instead of Required 18 Inches
CriticalCode Reference: 2022 California Mechanical Code
Category: Mechanical
Drawing Note 6 states that equipment in garages shall be installed so that pilots or burners are 'at least floor level.' This statement contradicts the California Mechanical Code Section 305.1, which explicitly requires all burners and burner-ignition devices to be located not less than 18 inches above the floor unless listed as flammable vapor ignition resistant. The note's wording implies floor level installation is acceptable, which would violate the 18-inch minimum requirement.
Why it matters: Installing ignition sources at floor level in garages creates a fire and explosion hazard. Gasoline vapors are heavier than air and accumulate at floor level. Ignition sources must be elevated to prevent contact with flammable vapors.
Suggested next step: Update Note 6 to require ignition sources to be located not less than 18 inches above the floor per CMC 305.1. Correct the code reference from UMC Section 308 to CMC Section 305.1.
Party Wall/Seismic Joint Detail Prohibits Joint Protection Material (Violates Fire Wall/Joint Protection)
CriticalCode Reference: 2024 International Building Code
Category: Fire Protection
The details labeled as party wall/seismic joint explicitly instruct: 'DO NOT INSTALL ANY MATERIAL WITHIN THIS GAP AT ALL.' Under the IBC, a 'party wall' is required to be constructed as a fire wall, and joints in or between fire-resistance-rated walls/floor assemblies are required to be protected with an approved fire-resistant joint system. An intentionally empty, unprotected seismic joint at a party wall conflicts with these requirements because it does not provide required continuity/fire resistance at the separation.
Why it matters: An unprotected joint in a fire wall creates a path for fire and smoke to spread between buildings, compromising the fire separation and creating a life safety hazard. Fire walls must maintain continuity to prevent fire spread.
Suggested next step: Remove the prohibition on joint protection material. Provide an approved fire-resistant joint system that maintains the required fire-resistance rating while accommodating seismic movement per IBC requirements.
Water Closet Flush Volume Exceeds Code Maximum (1.6 GPF Specified vs 1.28 GPF Required)
CriticalCode Reference: 2022 California Plumbing Code
Category: Plumbing
The general plumbing notes specify water closets at 1.6 gallon per flush maximum. The 2022 California Plumbing Code Section 411.2 requires water closets to not exceed 1.28 gallons per flush. The drawing explicitly states a higher flush volume (1.6 GPF) than code permits (1.28 GPF), a difference of 0.32 gallons per flush.
Why it matters: Exceeding the maximum flush volume violates water efficiency requirements and may result in permit rejection. California has strict water conservation requirements that must be met for new construction.
Suggested next step: Update plumbing notes to require water closets with maximum 1.28 GPF per CPC 411.2. Verify all specified fixtures meet current water efficiency standards.
Interior Garage Wall Keynote Specifies Single-Sided GWB Which Does Not Achieve Required 1-Hour Fire-Resistance Rating
CriticalCode Reference: 2024 International Building Code
Category: Fire Protection
Keynote 4 specifies 'TYP. INTERIOR WALL @ GARAGE: 5/8" TYPE X GWB OVER WOOD STUDS PER STRUC WITH R-13 INSULATION' which describes gypsum board on only one side of the wood studs. Per prescriptive fire-resistance requirements, a wood stud wall with single layer 5/8" Type X GWB on one side only does not achieve 1-hour fire-resistance rating. The wall separating the garage from the dwelling unit is required to be a fire partition per Section 420.2 and must have a minimum 1-hour fire-resistance rating per Section 708.3.
Why it matters: A non-rated wall between garage and dwelling unit allows fire and toxic gases to spread into living spaces, creating a severe life safety hazard. Garages contain flammable materials and vehicles that pose fire risks.
Suggested next step: Update Keynote 4 to require 5/8" Type X GWB on both sides of studs to achieve 1-hour fire-resistance rating. Verify the assembly meets IBC requirements for fire partitions.
Main Service Size is Unclear: Single-Line Shows New 400A Main, Load Calcs Specify 600A Main
CriticalCode Reference: 2024 International Building Code
Category: Electrical
The single-line diagram identifies a 'NEW 400A ... METER BOARD "MAIN"' while the load calculations state the 'MAIN PANEL' is '= 600 Amps.' This is a direct inconsistency in the permitted construction documents, creating an unclear basis for utility coordination, equipment selection, and installation.
Why it matters: Conflicting service size specifications create ambiguity that could result in incorrect equipment installation, utility connection issues, or insufficient capacity. The contractor cannot determine which size to install.
Suggested next step: Reconcile the discrepancy between single-line diagram and load calculations. Verify actual load requirements and update both documents to consistently specify the correct service size.
Party Wall Assembly Does Not Meet Required 2-Hour Fire-Resistance Rating for Fire Walls
CriticalCode Reference: 2024 International Building Code
Category: Fire Protection
The drawing legend explicitly specifies the party wall assembly as 'DOUBLE ROW OF 2x (3x AT FIRST FLOOR) WOOD STUDS @ 16" O.C. W/ 5/8" TYPE X GWB EACH SIDE.' Per IBC Section 706.1.1, party walls must be constructed as fire walls. Table 706.4 requires fire walls for Group R-1 and R-2 occupancies to have a 3-hour fire-resistance rating (with 2-hour permitted in Type II or V construction per footnote a), and Group R-3 and R-4 requires 2-hour rating. The specified single layer of 5/8" Type X GWB on each side of a double stud wall typically achieves approximately 1-hour fire resistance per standard tested assemblies, not the required 2-hour minimum.
Why it matters: Insufficient fire-resistance rating for party walls allows fire to spread between buildings, creating a severe life safety hazard and property damage risk. Fire walls are critical for containing fires within a single building.
Suggested next step: Update party wall assembly to achieve minimum 2-hour fire-resistance rating. This may require additional layers of Type X GWB or alternative construction methods per tested assemblies.
Showerhead Maximum Flow Rate Exceeds Code Limit (2.5 GPM Specified vs 1.8 GPM Required)
CriticalCode Reference: 2022 California Plumbing Code
Category: Plumbing
General Note 19 on the drawing specifies that all showerheads shall have a maximum flow rate of 2.5 gallons per minute (GPM). However, Section 408.2 of the 2022 California Plumbing Code explicitly requires showerheads to have a maximum flow rate of not more than 1.8 GPM at 80 psi. The specified flow rate exceeds the code-mandated maximum by 39%.
Why it matters: Exceeding the maximum flow rate violates water efficiency requirements and may result in permit rejection. California has strict water conservation standards that must be met.
Suggested next step: Update General Note 19 to require showerheads with maximum 1.8 GPM per CPC 408.2. Verify all specified fixtures meet current water efficiency standards.
Project Context
This residential rowhomes project involved the construction of multiple attached dwelling units with garages, requiring careful coordination of fire separation, life safety systems, and California-specific code requirements including water efficiency and energy standards.
The AI review identified critical life safety issues including missing carbon monoxide detection systems, incorrect fire-resistance ratings for party walls and garage separations, and prohibited materials in wet areas. Multiple outdated code references (2004-2007 editions) were found throughout the documents, indicating the design was based on obsolete standards.
California-specific requirements were frequently violated, including water efficiency standards (1.28 GPF for water closets, 1.8 GPM for showerheads), energy code compliance, and seismic design requirements for high seismic areas.
Key Challenges
- Multiple attached dwelling units requiring proper fire separation
- California-specific water efficiency and energy code requirements
- Seismic Design Category D requiring special moment frames
- Outdated code references throughout the document set
- Life safety systems including CO detection and fire protection
- Coordination between architectural, structural, and MEP systems
Impact of Finding These Issues Early
Prevented Life Safety Hazards
Critical issues like missing carbon monoxide detection, insufficient fire-resistance ratings, and incorrect garage equipment installation would have created severe life safety hazards. Finding these before construction prevented potential injuries or loss of life.
Avoided Permit Rejection
Multiple code violations including water efficiency violations, outdated code references, and non-compliant seismic design would have resulted in permit rejection, requiring complete redesign and resubmission with significant delays.
Prevented Structural Failures
Using ordinary moment frames in Seismic Design Category D and inadequate structural connections would have violated seismic design requirements and could result in structural failure during an earthquake in this high seismic area.
Resolved Code Compliance Issues
Over 370 issues including outdated code references (2004-2007 editions), water efficiency violations, and California-specific requirement non-compliance 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