Reference

Accessibility Modification Glossary

Plain-language definitions for terms used throughout this site and in the accessibility modification industry.

ADA (Americans with Disabilities Act): Federal civil rights law enacted in 1990 that prohibits discrimination against people with disabilities in employment, public accommodations, transportation, and government services. ADA accessibility standards technically apply to public facilities, not private residences, but the ADA Standards for Accessible Design are widely used as best-practice benchmarks for residential accessibility modifications.
AGI (Adjusted Gross Income): Your total gross income minus specific deductions (retirement contributions, student loan interest, etc.), before itemized deductions are applied. Used to calculate eligibility for some income-based grant programs and the 7.5% floor for the medical expense tax deduction.
ASME A17.1: The American Society of Mechanical Engineers Safety Code for Elevators and Escalators. Most states adopt this standard for residential elevators, requiring permits and periodic inspection.
ASME A18.1: The ASME Safety Standard for Platform Lifts and Stairway Chairlifts. Governs vertical platform lifts (VPLs) and inclined stair lifts in most states. Some states apply this standard to residential stair lifts; others do not.
Area Agency on Aging (AAA): Local organizations designated under the Older Americans Act to coordinate services for older adults. Most AAAs can connect homeowners with local home modification assistance, including free grab bar installation programs. Find your local AAA through the Eldercare Locator: 1-800-677-1116.
Blocking (Wall Blocking): Horizontal pieces of lumber (typically 2×6, 2×8, or 2×10) installed between wall studs behind the wall surface to provide a solid anchor for grab bars, handrails, and similar hardware. Standard residential walls do not have blocking; installing it typically requires opening the wall. The plywood backer panel method is an alternative that avoids wall opening.
Building Permit: An official approval from a local building department authorizing the construction, alteration, or demolition of a structure. Required for most structural, plumbing, electrical, and mechanical work. Permits ensure work is inspected for code compliance.
CAPS (Certified Aging in Place Specialist): A credential from the National Association of Home Builders (NAHB) indicating that a contractor, designer, or other professional has completed specialized training in home modifications for older adults and people with disabilities. CAPS is not a contractor's license but a training credential layered on top of an existing professional license.
CC&Rs (Covenants, Conditions, and Restrictions): The rules governing a homeowners association (HOA) community. CC&Rs cannot override the Fair Housing Act's reasonable modification provisions for disability-related home modifications.
CIL (Center for Independent Living): Consumer-directed nonprofit organizations serving people with disabilities. Many CILs offer home modification assistance, peer counseling, and help navigating funding programs. Find your local CIL through the National Council on Independent Living (ncil.org).
Conveyance: A regulatory term for any device that transports people or goods vertically (or along stairs). Elevators, vertical platform lifts, and in many states stair lifts, are classified as conveyances and subject to elevator safety codes requiring permits and periodic inspection.
Curbless Shower (Zero-Threshold Shower): A shower with no raised curb or lip at the entry, allowing a wheelchair or shower chair to roll directly in. The shower floor slopes toward the drain (typically 1/4” per foot). Also called a roll-in shower when designed specifically for wheelchair access.
DIRECT (in ads.txt): An IAB Tech Lab designation in an ads.txt file indicating that the publisher (website owner) has a direct relationship with the specified ad network. Required for Google AdSense: "google.com, pub-XXXXXXXXXXXXXXXX, DIRECT, f08c47fec0942fa0"
Fair Housing Act (FHA): Federal law (42 U.S.C. § 3604) prohibiting housing discrimination based on race, color, national origin, religion, sex, familial status, and disability. Section 804(f)(3)(A) specifically requires housing providers (including HOAs and landlords) to permit persons with disabilities to make reasonable modifications at their own expense.
FHEO (Fair Housing and Equal Opportunity): The office within HUD responsible for enforcing the Fair Housing Act. FHEO investigates fair housing complaints filed against HOAs, landlords, and other housing providers. File complaints at hud.gov/program_offices/fair_housing_equal_opp/online-complaint.
Frost Line: The maximum depth at which the ground freezes in a given climate zone. Footings for permanent structures (including wheelchair ramps) must extend below the frost line to prevent heaving from freeze-thaw cycles. Frost line depth ranges from 0 inches in southern states to 48+ inches in northern states.
GFCI (Ground Fault Circuit Interrupter): An electrical safety device required by code in wet areas (bathrooms, kitchens, outdoors) that cuts power within milliseconds if it detects an imbalance suggesting current is flowing through an unintended path (such as a person). Required for any new electrical outlets in bathroom accessibility projects.
Grab Bar: A horizontal, angled, or vertical bar securely mounted to a wall to provide support and stability in bathrooms. Must be anchored into wall studs or solid blocking; never into drywall alone. ADA-standard diameter is 1.25–1.5 inches; must support a 250-lb concentrated load in any direction.
HCBS (Home and Community-Based Services): Medicaid services funded through Section 1915(c) waivers that allow states to cover services in home and community settings rather than institutional settings. HCBS waivers in most states cover home modifications as part of a person-centered care plan.
HISA (Home Improvement and Structural Alterations): A VA healthcare benefit that provides grants for medically necessary home modifications. Current limits: $11,536 for service-connected veterans; $8,709 for non-service-connected. Administered through VAMC Prosthetics departments.
HOA (Homeowners Association): An organization in a planned community that enforces CC&Rs and manages common areas. HOAs cannot deny disability-related reasonable modification requests under the Fair Housing Act, regardless of what their CC&Rs say.
HUD (Department of Housing and Urban Development): Federal agency responsible for national housing policy and enforcing the Fair Housing Act. HUD's FHEO office investigates housing discrimination complaints.
IPL (Inclined Platform Lift): A platform (rather than a seat) that travels along a rail on a staircase, allowing a wheelchair to remain on the platform during travel. Different from a stair lift (which has a seat) and requires a wider staircase. Regulated as a conveyance under ASME A18.1.
IRC (International Residential Code): A model building code published by the International Code Council, adopted (with local amendments) by most U.S. states and municipalities. The IRC governs construction standards for one- and two-family dwellings, including structural requirements relevant to accessibility modifications.
Load-Bearing Wall: A wall that supports structural weight from above (roof, upper floors). Modifications to load-bearing walls (widening doorways, removing sections) require structural engineering review in some jurisdictions and always require a building permit. Non-load-bearing (partition) walls carry only their own weight and are less complex to modify.
Medicaid HCBS Waiver: See HCBS.
Modular Ramp: A pre-engineered, removable ramp system (typically aluminum) that is assembled from standard sections on site. Classified as equipment rather than a permanent structure in all U.S. jurisdictions, meaning no building permit is required. Can be disassembled and moved.
Nosing: The front edge of a stair tread that overhangs the riser below. Nosings that are not clearly visible (no contrast with the tread surface) are a fall hazard. High-contrast nosing strips (adhesive or painted) are a low-cost safety improvement for any staircase.
Occupational Therapist (OT): A licensed healthcare professional who helps people perform daily activities. OTs with home modification training can conduct home assessments, identify accessibility barriers, and recommend specific modifications. VA OTs are often the primary contact for initiating a HISA grant. OTs with the ATP (Assistive Technology Professional) credential have additional expertise in home modification equipment.
Offset Hinge (Swing-Clear Hinge): A door hinge that swings the door completely clear of the doorframe when open, gaining 1.5–2 inches of additional clear width. A low-cost alternative to full doorway widening for marginal width situations. Costs $20–$60 per door, no permit required, no structural work.
Plywood Backer Panel: A sheet of 3/4-inch plywood installed over an existing wall surface to provide a solid substrate for grab bars, eliminating the need to open the wall to install blocking. Legal and code-compliant; avoids the permit requirement associated with wall opening. Adds approximately 3/4 inch of thickness to the wall surface.
Pressure-Balance Valve: A shower valve that automatically maintains a constant ratio of hot and cold water, preventing scalding if cold water pressure drops (e.g., when a toilet is flushed). Required by code in new construction in most states; recommended for any bathroom remodel involving older adults or people with limited sensation.
PSAS (Prosthetics and Sensory Aids Service): The department within VA Medical Centers that processes HISA grant applications and manages durable medical equipment. The first point of contact for veterans applying for the HISA benefit.
Reasonable Modification: Under the Fair Housing Act, a structural change to a dwelling or common area that is necessary to afford a person with a disability equal opportunity to use and enjoy the housing. Must be related to the disability and not impose an undue burden on the housing provider. Wheelchair ramps, grab bars, and roll-in shower conversions are classic examples.
Roll-In Shower: A curbless shower designed to allow a wheelchair to roll directly onto the shower floor without crossing any threshold or curb. Requires a floor sloped toward the drain, minimum 36×36-inch space (60×30 preferred), and grab bars. See also: Curbless Shower.
Rise / Run (Ramp): Rise is the vertical height of a ramp (how high it climbs). Run is the horizontal distance of the ramp. The ADA slope standard of 1:12 means one inch of rise requires one foot (12 inches) of run. A 24-inch rise requires a minimum 24-foot-long ramp at 1:12 slope.
SAH (Specially Adapted Housing Grant): VA grant providing up to $109,986 (FY2025) for veterans with specific qualifying service-connected disabilities to build, buy, or adapt a home. Distinct from and more generous than the HISA grant; requires specific disability criteria.
Section 504 (USDA): The USDA Rural Development Very Low-Income Housing Repair program providing grants (up to $10,000 for homeowners 62+ with very low income) and loans (up to $40,000 at 1%) for home repairs and accessibility improvements in rural areas. Not to be confused with Section 504 of the Rehabilitation Act.
Section 504 (Rehabilitation Act): A federal civil rights law prohibiting discrimination against people with disabilities in programs receiving federal financial assistance. Applies to federally assisted housing, requiring those housing providers to make accessibility modifications at their own expense (unlike FHA which requires tenants to pay).
SHA (Special Home Adaptation Grant): VA grant providing up to $22,036 (FY2025) for veterans with specific qualifying service-connected disabilities to adapt an existing home. For veterans who do not meet SAH criteria but have qualifying disabilities including blindness in both eyes or loss of both hands.
Slope (Ramp): The angle of inclination of a ramp surface, expressed as a ratio of rise to run. The ADA standard for accessible ramps is a maximum slope of 1:12. Steeper slopes (1:10, 1:8) may be permissible in constrained spaces but require more effort to navigate and are not recommended for independent manual wheelchair use.
Stair Lift (Chair Lift): A motorized chair that travels along a rail mounted to a staircase, carrying a rider between floors. Straight rail lifts serve single straight staircases; curved rail lifts are custom-fabricated for staircases with turns or landings. Regulated as conveyances in some states (requiring permits), classified as home appliances in others.
Threshold Ramp: A small ramp (typically rubber or aluminum, 1/2–4 inches high) placed at a door threshold to create a smooth transition and eliminate the tripping hazard of a raised threshold. No permit required anywhere. The simplest and least expensive accessibility modification.
TRA (Temporary Residence Adaptation): A VA grant allowing SAH- or SHA-eligible veterans to adapt a family member's home where they are temporarily residing. Funds are drawn from the SAH/SHA lifetime maximum. TRA limit: up to $46,494 for SAH-eligible veterans, $9,315 for SHA-eligible.
Transfer (Lateral Transfer): The process of moving from one seated surface to another (e.g., from a wheelchair to a toilet seat) by sliding sideways rather than standing and sitting. Transfers require clear lateral space beside the destination surface and are the reason toilet grab bar placement and 18-inch lateral clearance are so important.
Turning Radius (Wheelchair): The minimum floor space required for a wheelchair to complete a 180- or 360-degree turn. ADA standard for a full 360-degree turn: 60-inch diameter circle of clear floor space. This requirement drives many bathroom layout decisions, particularly in roll-in shower design.
Universal Design: An approach to design that creates environments, products, and communications usable by all people, to the greatest extent possible, without adaptation or specialized design. Applied to home modifications, universal design results in features that serve all household members at all life stages, rather than being perceived as disability-specific.
VAMC (VA Medical Center): A Veterans Affairs hospital and healthcare facility. HISA grant applications are processed through the Prosthetics and Sensory Aids Service (PSAS) at your local VAMC. Find your nearest VAMC at va.gov/find-locations.
VPL (Vertical Platform Lift): A powered lift that travels straight up and down (vertically), similar to a small open elevator without an enclosed cab. Used for level changes up to approximately 14 feet. Regulated as a conveyance under ASME A18.1 in all states; permits required everywhere.
VSO (Veterans Service Organization): Nonprofit organizations (such as DAV, American Legion, VFW, Paralyzed Veterans of America) that provide free claims assistance to veterans. VSO representatives can help veterans navigate HISA and SAH/SHA applications and appeals at no cost.
Walk-In Tub: A bathtub with a door in the side wall that allows entry without stepping over a high tub wall. The user must enter, close the door, fill the tub, bathe, drain the tub, then exit. Contrast with a roll-in shower, which allows immediate wheelchair entry. Best suited for ambulatory users who want to soak; less appropriate for non-ambulatory users.
Wall Stud: Vertical framing members (typically 2×4 or 2×6 lumber) spaced 16 inches on center in standard residential construction. Grab bars anchored directly into wall studs have the strongest possible hold. A stud finder locates studs behind finished wall surfaces.

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