Multnomah County is Oregon's densest and most populous county with Portland as the county seat and largest city, Gresham as the second-largest community on the east side, and Troutdale, Fairview, Wood Village, and Maywood Park rounding out the incorporated communities. The county is the smallest by land area among the I-5 corridor counties but holds roughly 815,000 residents -- more than 18 percent of the state's population. Paving here is a fundamentally different operation than anywhere else in Oregon -- continuous traffic, layered permitting authorities, the Portland 2025 building codes, Willamette Valley clay and Columbia River silt subgrade, and traffic-control overhead that adds 10 to 25 percent to typical job costs.
This guide covers Multnomah County subgrade, the Portland Bureau of Transportation (PBOT) and city permit ecosystem, the 2025 building code overlay, and 2026 cost ranges that reflect Portland-metro labor and code compliance.
Portland, Gresham, Troutdale, and the County Spread
Portland anchors the county with roughly 645,000 residents, the densest pedestrian network in Oregon, the Willamette and Columbia waterfronts, and one of the most complex permit environments in the state. Commercial paving demand is broad: downtown, the Lloyd District, the South Waterfront, the Pearl, the central eastside, North Portland industrial, the Killingsworth and Powell corridors, and continuous commercial development across the eastside. Add OHSU on Marquam Hill, the Portland International Airport (KPDX), the Port of Portland industrial properties, and dozens of medical and institutional campuses, and the county's paving market is the deepest in Oregon.
Gresham (110,000 residents) hosts the Mt. Hood Community College campus, a downtown commercial core, and the Highway 26 / I-84 / Powell Boulevard commercial corridors. Troutdale, Fairview, and Wood Village round out the east-county work with steady commercial and industrial paving along the Sandy River and I-84 frontage. Unincorporated Multnomah County is small -- the Sauvie Island agricultural area and a thin strip of west-hills forestland -- but generates rural-residential and agricultural paving demand.
For lot striping that follows new paving, see the Multnomah County parking lot striping guide.
Subgrade: Clay, Silt, and Cascade Foothill Basalt
Multnomah County subgrade splits across the geography:
- Willamette Valley clay (east Portland, Gresham, much of the residential grid) -- silty clay loam; standard valley-clay base design with geotextile under commercial work
- Columbia River silt (north and northwest Portland, Sauvie Island, Troutdale) -- silt and silty sand; variable; high water table in floodplain zones
- West Hills and forest park -- Cascade and Coast Range foothill basalt; steep grades; rock-hammer on hillside cuts
- River-edge industrial (Swan Island, Rivergate, port properties) -- engineered fill over Columbia silts; can require deep base sections
Standard base build for a Multnomah County commercial lot on clay:
- 14 to 22 inches of crushed-aggregate base
- Non-woven geotextile fabric over the subgrade
- 3 to 4 inch asphalt base lift
- 2 inch wear course
- 6 to 8 inches total mat thickness depending on use (heavier for truck, industrial, and airport-adjacent work)
For utility-trench, traffic-control, and site-prep work ahead of paving, the Multnomah County excavation guide covers the urban work mix.
Portland 2025 Building Codes and PBOT Permitting
Portland enforces the 2025 building code overlay alongside the city-specific stormwater, transportation, and right-of-way codes. Permit triggers stack quickly on commercial paving work:
- PBOT right-of-way permit -- any work that touches public right-of-way, sidewalk, curb, or driveway approach
- City stormwater code (BES) -- triggered on impervious-surface thresholds that vary by overlay zone; commonly 500 to 1,000 sq ft of new or replaced impervious surface in inner-city areas
- Construction traffic management plan -- often required for any closure of a travel lane or sidewalk
- 2025 building code -- accessibility, parking-stall count and dimensions, ADA-accessible routes
- Tree protection -- mature street tree work or root-zone disturbance triggers Bureau of Environmental Services permitting
Permit lead times in Portland run 8 to 16 weeks for medium-to-large commercial projects. Engineering and permit-coordination costs commonly add $8,000 to $30,000 on top of the paving bid for triggered projects.
Gresham, Troutdale, and Fairview have their own permit processes but with generally simpler stormwater and right-of-way triggers than Portland.
Climate and Traffic-Control Overhead
Multnomah County paving runs on the standard Willamette Valley calendar -- late May through mid-October optimal, with wet-season shutdown November through April. The compressed window forces dense commercial work into 5 to 6 months of the year. Traffic-control overhead is the variable people forget -- urban paving frequently requires flagging, off-peak scheduling (nights and weekends), and detour signage that adds 10 to 25 percent to job cost versus a comparable rural lot.
Pair every paving job with a Multnomah County sealcoating cycle every 2 to 3 years. UV and traffic wear in the Portland urban core demand disciplined surface maintenance.
Industry Baseline Range
Industry Baseline Range
| Project Type | Typical Size | Baseline Cost Range |
|---|---|---|
| Small commercial lot | 5,000 to 10,000 sq ft | $26,000 to $58,000 |
| Medium commercial lot | 10,000 to 25,000 sq ft | $58,000 to $145,000 |
| Large commercial / hospital / industrial lot | 25,000 to 150,000 sq ft | $145,000 to $750,000+ |
| Residential driveway | 600 to 2,000 sq ft | $4,800 to $15,000 |
| HOA / apartment drive lane | per linear foot, 22 ft wide | $48 to $85 per linear ft |
| Mill and overlay | per sq ft | $5.00 to $8.00 per sq ft |
| Full-depth replacement (urban) | per sq ft | $8.50 to $15.50 per sq ft |
Current Market Reality
Multnomah County paving prices commonly run 15 to 30 percent above statewide medians because of stacked factors -- Portland-metro labor rates, permit and engineering overhead, traffic-control requirements, prevailing-wage exposure on institutional work, and clay-subgrade base requirements. 2026 delivered hot-mix cost has climbed roughly 20 percent over 2022. For statewide context, the Oregon asphalt paving cost ranges breakdown documents how Portland-metro pricing compares to outlying counties.
Selecting a Multnomah County Paving Contractor
The Portland paving market is competitive but bid quality varies widely. Things to verify on every bid:
- CCB license, active Oregon insurance, worker's comp, and Portland business license
- PBOT-permit experience and traffic-control plan capability
- 2025 building code and BES stormwater code experience
- Itemized base prep, mat thickness, geotextile, tack coat, and compaction lines
- Documented compaction-test plan
- References from comparable Multnomah County projects
- Realistic schedule that accounts for permit lead times and traffic-control coordination
Lump-sum bids without itemized engineering and explicit traffic-control scope are how Portland projects blow their budgets mid-job.
Schedule Your Multnomah County Paving Job
Cojo paves Multnomah County from downtown Portland through Gresham, Troutdale, Fairview, and Sauvie Island. We bid every job with itemized engineering, traffic-control scope, and pair the work with an asphalt maintenance program so urban wear and clay subgrade do not cut pavement life short.
Schedule a site walk and we will document your subgrade, identify permit triggers, and write a bid that fits Portland-metro conditions.