When altering an existing building, any new work must comply with the currently adopted accessibility standard, typically ICC A117.1 as referenced by the International Building Code (IBC). However, codes recognize the unique challenges of existing construction and provide specific exceptions and limitations.

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For architects, engineers, and contractors, the primary considerations are the "path of travel" requirements and the concept of "technical infeasibility."

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• Primary Function Area Trigger: An alteration to a "primary function area" (e.g., a sales floor, office space, or dining room) triggers the requirement to make the path of travel to that area accessible. This includes the entrance, the route to the altered area, and the primary public toilet rooms, drinking fountains, and telephones serving the area.
• 20% Cost Limitation: The cost of these path of travel upgrades is not unlimited. Per the IBC and the Americans with Disabilities Act (ADA), this expenditure is capped at 20% of the total cost of the alteration to the primary function area itself. This is often called the "disproportionality rule."
• Technical Infeasibility: When existing structural conditions or site constraints make full compliance impossible, the codes allow for exceptions. This is not a blanket waiver but a high standard that must be thoroughly documented. For example, moving a load-bearing wall to achieve a 60-inch turning circle might be deemed technically infeasible.
• Historic Building Exceptions: Qualified historic buildings are granted specific latitude where full compliance would threaten or destroy the historic character of the facility. This often requires consultation with the State Historic Preservation Officer (SHPO).

Alternative Maneuvering Clearances: ICC A117.1 provides technical alternatives to standard clearances. The most common is the T-shaped turning space, which can be used in place of the 60-inch circular turning space where conditions are constrained.

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Why Does ANSI 117A.1 Matters in Existing Buildings?

Applying modern accessibility standards to buildings constructed decades or even a century ago is one of the most complex challenges in design and construction. While new buildings are designed around accessibility from day one, existing facilities are constrained by fixed structural elements, tight floor plans, and established site conditions.

This topic is critical because it sits at the intersection of several legal and regulatory frameworks:

• International Building Code (IBC) / International Existing Building Code (IEBC): These model codes, adopted by most jurisdictions, provide the primary permitting requirements for alterations. They reference ICC A117.1 for technical standards.
• Americans with Disabilities Act (ADA): This federal civil rights law mandates accessibility in public accommodations. While the ADA Standards for Accessible Design are closely aligned with the IBC and A117.1, compliance with local building codes does not automatically guarantee compliance with the ADA.
• ICC A117.1 (Accessible and Usable Buildings and Facilities): This is the technical "how-to" standard. It specifies the dimensions, slopes, forces, and layouts required for accessible elements, but it does not dictate when those elements must be provided in an alteration—that is the role of the IBC and ADA.

A common misunderstanding is that any renovation requires the entire building to be brought up to current code. This is incorrect. The codes provide a pragmatic framework focused on the altered area and the path of travel leading to it, balanced by the 20% cost cap to prevent unreasonable financial burdens. Properly navigating these rules is essential for successful permitting, avoiding costly change orders, and ensuring meaningful access for all users.

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I am designing an alteration to a historic building where achieving the full 60-inch turning circle in an existing toilet room is technically infeasible. What are the specific exceptions and alternative maneuvers (e.g., T-shaped turn) allowed by ICC A117.1, and what level of documentation is required to justify this to the plan reviewer?

When full compliance with maneuvering clearances is technically infeasible in a qualified historic building, you can utilize alternative layouts and must provide robust documentation to justify the exception. The key is to demonstrate that achieving the standard clearance would threaten or destroy the building's historic significance.

The technical alternative to the 60-inch turning circle is explicitly provided within the referenced standard itself. The ICC A117.1-2017 Section 304.3.2 details the requirements for a T-Shaped Space. This is a 60-inch by 60-inch area with arms and a base at least 36 inches wide, which allows for a three-point turn for a wheelchair user. This is a fully compliant alternative and can be used in any project where space is constrained, but it is particularly useful in historic renovations.

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Code Basis for the Exception

The authority to deviate from standard requirements in historic buildings comes from the building code and the ADA, not from ICC A117.1.

• International Building Code (IBC 2021 §3411) or International Existing Building Code (IEBC 2021 §1205): These sections govern historic buildings. They state that alterations shall comply with the code's accessibility provisions, unless it is determined that compliance would threaten or destroy the historical significance of the building. In such cases, alternative compliance is permitted.
• 2010 ADA Standards §202.5: This section mirrors the IBC. It applies to facilities that are "eligible for listing in the National Register of Historic Places" or are "designated as historic under State or local law." It allows for alternative requirements if the State Historic Preservation Officer (SHPO) or other designated authority determines that standard compliance would "threaten or destroy the historic significance of the building."

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Documentation Required for Plan Review

To justify using an alternative like a T-shaped turn due to historic constraints, you must provide a compelling case to the building official or plan reviewer. Your documentation package should include:

• Formal Historic Designation: Proof that the building is a qualified historic facility.
• Statement from a Preservation Authority: A letter or formal opinion from the SHPO or a local historic preservation board confirming that the proposed alteration required for full compliance (e.g., moving a historic load-bearing masonry wall) would indeed threaten or destroy significant historic features.
• Detailed Architectural Plans:
  
  • An "existing conditions" plan showing the toilet room and its constraints (e.g., load-bearing walls, historic fixtures or finishes to be preserved, shafts).
  • A "demolition plan" showing the minimal work proposed.
  • A "proposed plan" clearly dimensioning the T-shaped turning space in compliance with ICC A117.1 §304.3.2.
• Written Narrative: A clear, concise letter or narrative on the drawings explaining:
  
  • What the standard requirement is (60-inch turning circle per ICC A117.1 §603.2.1).
  • Why it is technically infeasible to meet it, specifically linking the required work to the destruction of historic fabric (e.g., "Achieving a 60-inch circle would require demolishing a 12-inch thick plaster-on-terracotta load-bearing partition, which is an original and character-defining feature of the building...").
• The proposed alternative (the T-shaped turn) and a reference to the code section that permits it (ICC A117.1 §304.3.2).

By providing this comprehensive documentation, you show the plan reviewer that you have followed due process, consulted the proper authorities, and are providing a compliant alternative recognized by the accessibility standard.

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In a large commercial renovation, what triggers the requirement to upgrade the entire path of travel to comply with the current ANSI standard, and what are the limits on the cost of these upgrades relative to the total project cost?

The requirement to upgrade the path of travel is triggered when an alteration is made to a primary function area in a commercial building. The cost of these upgrades is limited to 20% of the cost of the alteration to the primary function area itself.

This fundamental requirement ensures that as buildings are modernized, accessibility is improved in tandem, without forcing a full, cost-prohibitive upgrade of the entire building for a minor renovation.

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The "Primary Function Area" Trigger

The codes define a primary function area as a space where the main activities for which the facility is intended take place.

• Definition: According to IBC 2021 Chapter 2 and ADA §106.5, this includes areas like the customer service lobby of a bank, the dining area of a restaurant, the offices and conference rooms of a business, and the retail floor of a store.
• Exclusions: It specifically excludes areas like mechanical rooms, boiler rooms, employee-only locker rooms, storage rooms, and janitorial closets.

If your renovation project consists only of work in these excluded areas (e.g., replacing a boiler), the path of travel upgrade requirement is not triggered. However, if you are renovating an office suite (a primary function area), you must also address the accessibility of the path leading to it.

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Required Path of Travel Upgrades

When triggered, IBC 2021 §1109.8 requires the following elements along the path of travel to be made accessible:

• The path from the building entrance to the altered primary function area.
• The restrooms serving the altered area.
• The public telephones serving the altered area.
• The drinking fountains serving the altered area.

All upgrades must meet the technical requirements of the adopted ICC A117.1 standard.

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The 20% Cost Limitation (Disproportionality Rule)

The codes place a critical financial limit on these required upgrades.

• Code Reference: IBC 2021 §1109.8.1 and ADA §202.4 Exception state that the cost of providing an accessible path of travel is not required to exceed 20% of the cost of the alteration to the primary function area.
• How it Works: This creates a "safe harbor" against disproportionate costs. The 20% is calculated based only on the construction costs for the work within the primary function area. It does not include costs for the path of travel upgrades themselves or other unrelated work in the building.

Example Calculation:

• Project: A tenant renovates their 5,000 sq. ft. office space.
• Cost of Alteration to Primary Function Area: $250,000
• Maximum Required Path of Travel Expenditure: 20% of $250,000 = $50,000
• Identified Barriers: The corridor to the suite has a non-compliant door ($5,000 to fix), and the building's main public toilet rooms are not accessible ($65,000 to renovate).
• Obligation: The owner must spend up to $50,000 on path of travel upgrades. They are not obligated to spend the full $70,000 required to fix everything. They would spend the $50,000 on the highest-priority items (see "Prioritizing Upgrades" section below).

This 20% rule is a project-by-project obligation. If the same tenant expands and renovates another area two years later, a new 20% calculation would be made based on that new project's cost.

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Additional Supporting Sections

Defining "Technically Infeasible"

The term "technically infeasible" is a formal code definition and represents a very high standard. It is not a matter of opinion or simple expense. The ADA at §106.5 defines it as an alteration that has "little likelihood of being accomplished because existing structural conditions would require removing or altering a load-bearing member which is an essential part of the structural frame; or because other existing physical or site constraints prohibit modification."

To claim technical infeasibility, you must document:

• Structural Conflict: The required alteration would necessitate changing a primary load-bearing element (e.g., column, foundation, load-bearing wall).
• Physical or Site Constraint: The change is physically impossible without moving the building or a property line (e.g., adding a ramp with the required length is not possible on a steep, constrained site).

Cost alone is not a reason for a technical infeasibility claim. The 20% disproportionality rule is the mechanism for addressing excessive cost.

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Coordination Between IBC, ADA, and Local Codes

Successful compliance requires understanding how the different regulations work together:

• IBC/IEBC: Provides the prescriptive requirements for permitting. The building department enforces this code.
• ICC A117.1: The technical standard that gives you the "how-to" dimensions and specifications. It is not a standalone code but is adopted by reference in the IBC.
• ADA: A federal civil rights law enforced by the Department of Justice. A project can receive a building permit and still be found non-compliant with the ADA. Because the 2010 ADA Standards are very closely harmonized with the IBC/A117.1, complying with the stricter of the requirements usually ensures compliance with both.

State and Local Codes: Many jurisdictions, like California (CBC Chapter 11B), Florida (FBC, Accessibility), and Texas (Texas Accessibility Standards), have their own accessibility codes that may be more stringent than the model codes. The local, adopted code always takes precedence.

Prioritizing Path of Travel Upgrades

When the total cost of removing all path of travel barriers exceeds the 20% cap, the owner must spend their budget on upgrades in a specific order of priority, as outlined in ADA §202.4. The priorities are:

• An accessible entrance to the building.
• An accessible route to the altered primary function area.
• Accessible restrooms for each sex, or a single unisex restroom.
• Accessible public telephones.
• Accessible drinking fountains.
• Other accessible elements such as parking, storage, and alarm systems.

You must spend the full 20% on this list, in this order, until the money runs out.

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Frequently Asked Questions (FAQ)

What is the difference between the 2010 ADA Standards and ICC A117.1?

The ADA Standards are part of a federal law that includes both scoping requirements (when and where you need accessible elements) and technical requirements (how to build them). ICC A117.1 is a voluntary standard developed through a consensus process that contains only technical requirements. The IBC adopts A117.1 for its technical standards, and its scoping is very similar to the ADA's.

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Does a simple cosmetic upgrade, like painting and new carpet, trigger path of travel requirements?

Generally, no. The ADA and IBC define an "alteration" as a change that affects the usability of a facility. Purely cosmetic work like painting, re-carpeting, or changing wall coverings typically does not trigger the path of travel upgrade requirements.

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Do I have to bring the entire building up to code if I just renovate one office?

No. The requirement is limited to the new work within the altered area and the path of travel leading to it, and even that is capped at 20% of the project cost. The rest of the building can remain as-is.

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What version of ICC A117.1 should I use?

You must use the version of ICC A117.1 that has been officially adopted by your state or local jurisdiction. This is typically specified in the adopted version of the International Building Code. For example, the 2021 IBC references the 2017 edition of ICC A117.1.

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Is the 20% cost limit based on the total construction cost or just the altered area?

It is based only on the construction costs for the alteration of the primary function area itself.

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Are T-shaped turns only allowed in historic buildings?

No. The T-shaped turning space detailed in ICC A117.1 §304.3.2 is a standard, fully compliant alternative to the 60-inch circular space. It can be used in any building, new or existing, where that configuration is more efficient for the design.

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Can our firm get a "waiver" for accessibility requirements from the building department?

Waivers are extremely rare and generally not granted. The proper code mechanism for dealing with impossible situations is to prove "technical infeasibility," which allows for alternative compliance but does not waive the requirement for accessibility entirely.

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What happens if there is no accessible path of travel to the area I'm renovating?

If you are altering a primary function area, you are obligated to create one. You must spend up to 20% of your project's cost to establish that path, starting with the highest priority item (usually the building entrance) and working inward.

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References

1. ICC A117.1–2017: Accessible and Usable Buildings and Facilities (Official Standard – Digital Viewer): https://codes.iccsafe.org/content/icca117-12017/american-national-standard
2. 2010 ADA Standards for Accessible Design – Ramps, Curb Ramps, and Walking Surfaces (Sections 403, 405, 406, 303, 307): https://www.ada.gov/law-and-regs/2010-ada-standards-for-accessible-design/
3. ICC Curb Ramp & Pedestrian Access Technical Guide (Curb Ramp Geometry, Flares, Detectable Warnings): https://www.iccsafe.org/advocacy/accessibility/accessible-means-of-egress-and-curb-ramps/
4. International Existing Building Code (IEBC) 2021 – Chapter 12: Historic Buildings (Alternative Compliance for Historic Structures): https://codes.iccsafe.org/content/IEBC2021P1/chapter-12-historic-buildings
5. ADA Guide for Small Businesses – Barrier Removal, Alterations, Path of Travel, and Prioritization: https://www.ada.gov/resources/smbusgd/

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