Curb ramps are the line items an inspector measures with a digital level, and a slope that is one percent off fails. On an industrial site, accessible routes connect parking, the main entrance, the break room and any visitor area, and each element has dimensional limits written into the standard. The routes also have to work with forklift traffic, snow storage and deicers. We build site concrete so that it passes the first inspection and still works in the fifth winter.
The scope runs from sidewalks and curb and gutter to ramps, landings, accessible stalls and access aisles, loading dock approaches, bollard bases, equipment pads and the small flatwork that holds a site together. Because those pieces cross other trades' work, we pour them last in each area, after underground utilities are tested and the base has been proofed, and we mark the accessible route on the plan so no later trade blocks it.
Many of the problems we are asked to repair come from design drawings that never reconciled the architect's accessible route with the civil engineer's grades. We catch those conflicts in preconstruction, because a ramp that does not fit its landing is cheaper to fix on paper.
Slopes, edition lookups and who reviews the work
The accessibility standard sets a maximum running slope of 1:20 (5 percent) for a walking surface that is not a ramp, a maximum 1:12 (8.33 percent) running slope for a ramp, and a maximum cross slope of 1:48 (2 percent). Accessible parking stalls and access aisles must be level to 2 percent in every direction. Those limits are narrow enough that concrete finishers need a plan and a laser level, not a feeling. Detectable warning surfaces at curb ramps are installed in the wet concrete.
The building code layered on top varies by jurisdiction. The Home Builders Association of Metro Denver tracker dated January 20, 2026 shows Adams County, Arvada and Castle Rock on the 2018 I-codes, Aurora and Arapahoe County on 2021, and Boulder, Golden and Cherry Hills Village on 2024. The Boulder tracker entry also lists the Boulder Energy Conservation Code, which applies since August 1, 2025. We confirm the edition and local amendments for your parcel before detailing the work, since accessible route requirements are often tied to those editions.
What drives the price of flatwork
Flatwork cost depends on quantity, access and weather. Small-quantity placements in several areas cost more per yard than one large pour because each requires forming, finishing crew time and a truck. Hand-finishing ramps and landings is slower than machine-finishing an apron, and we price it accordingly. Cold-weather protection is another line: blankets, heaters and slower production when overnight lows fall below freezing.
Design depth also matters. The frost depth in the design criteria for Lakewood is 36 inches, and similar numbers appear in other Front Range jurisdictions. Thickened edges, doweled joints and a stable base reduce long-term maintenance, and they are cheaper to build once than to repair later. We show the options as alternates so you can compare initial cost with the maintenance cost over time.
Components that make up the accessible route
Sidewalks, ramps, landings and accessible stalls are the visible parts. Behind them sit the base preparation, the control joints, the expansion joints at buildings and curbs, the rebar or fiber reinforcement and the detail at utility covers that must be flush. We install air-entrained concrete in exposed locations, which is the right choice for freeze-thaw and deicer exposure, and we cure it properly so the surface does not scale.
Near the building, we integrate the flatwork with dock aprons, door thresholds and the slab edge. Where trucks cross sidewalks, we thicken sections and use reinforcement, and we place bollards on drilled bases rather than shallow footings. The adjacent parking is covered under stabilized parking lots, and the heavy pavement around loading is covered under dock aprons and loading zones.
Where accessible routes get the most scrutiny
Industrial buildings with offices or visitor areas, and flex buildings that host many small tenants, get the most attention from inspectors. Medical and life-science tenants add requirements for patient or visitor access. See how we approach office building and medical office work on mixed-use industrial campuses, where a manufacturing plant may share a site plan with an administrative wing.
The same applies to laboratory and pharmaceutical sites, where the public-facing area is small but regulated. Our work for pharmaceutical and life sciences clients shows how a controlled production area and an accessible visitor route have to be separated cleanly. Redtail Ridge in Louisville, a 389 acre, 2.6 million square foot life sciences campus along U.S. 36, is an example of the scale at which these site plans operate.
Sequencing flatwork around the rest of the site
Concrete flatwork is easiest to schedule when it follows a rhythm: utilities and base first, forms next, then pour, cure and backfill. Accessible routes need a final survey before and after placement. We survey the forms before the truck arrives, because a ramp that fails slope with the concrete in place can only be fixed by removal. After pouring, we check each ramp and landing with a digital level and record the readings for the turnover package.
Winter pours need more planning. Boulder, Lakewood and other Front Range cities see freezing nights from fall through spring, and concrete placed in cold conditions needs protection. When a certificate of occupancy depends on the accessible route, we move the work earlier in the schedule or set up cold-weather enclosures, so a missing sidewalk does not hold up the opening. For Boulder-area sites, we also review the local energy and building requirements in Boulder early in the permit process.
Get the accessible route right before the pour
Send the civil and architectural plans and we will return a grade check, a flatwork scope and a cold-weather plan. Contact Industrial Contractors of Colorado to schedule a review.
Common Questions
Who is responsible for ADA compliance on the site?
Responsibility is shared. The design team is responsible for a compliant design, the contractor for building to it within tolerance, and the owner for operating the facility accessibly. We verify slopes and dimensions during construction and record them, so deviations are fixed before the inspector arrives.
How do you avoid failing the final accessibility inspection?
We check every ramp, landing and accessible stall with a digital level at the forming stage and again after the pour. Detectable warnings, signage and striping are checked against the drawings. Any deviation is corrected while the contractor still has forms and crews on site.
Can we pour accessible routes in winter?
Yes, with protection. We use heated enclosures or insulated blankets, and we avoid placing concrete on frozen subgrade. Winter pours cost more and take longer, but they can keep a certificate of occupancy date. We discuss that trade-off during scheduling.
What concrete mix do you use for exterior flatwork?
We use air-entrained mixes designed for freeze-thaw and deicer exposure, with strengths set by the engineer. Air content, slump and temperature are checked at delivery. Proper curing is just as important as the mix, and we plan for it.
Does the building code edition affect the site concrete?
It can. Some jurisdictions have local amendments to accessible route rules, and the edition adopted changes referenced standards. We confirm the edition with the building department before detailing, since changes between editions can affect the design.