Hillsboro RV park asphalt paving operates on Tualatin Plain clay subgrade with seasonal high groundwater, which changes the structural section requirement compared to better-draining sites. Owner-operators running Roamers Rest RV Park or other Washington County facilities supporting Class-A diesel pushers feel the consequence of an underspec'd pad within three to four years -- typically wheel-position rutting in the first season followed by base-pumping at the deeper occupancy levels. This article walks through what a Hillsboro RV park rebuild actually needs and what it costs in 2026.
Tualatin Plain Subgrade Conditions
Hillsboro sits on the Tualatin Plain with clay-heavy subgrade at most RV-park sites and seasonal high groundwater that runs within 3 to 5 feet of grade in many locations. Clay does not drain, so any RV pad sitting over clay has to handle drainage through the structural section and the surrounding swales rather than infiltration. The aggregate base section typically runs 10 to 14 inches on the clay subgrade, with geotextile fabric reinforcement at sites where the water table is high enough to pump fines into the base.
Washington County stormwater rules apply to any project disturbing more than 500 square feet of impervious surface. An RV park rebuild crosses that threshold easily, which adds 2 to 6 weeks of permit lead time and may require a stormwater management plan. See Oregon asphalt cost benchmarks for the broader cost frame.
Class-A Coach Wheel-Load Mix Design
A Class-A motorhome carries axle weights in the 12,000 to 22,000 pound range -- significant static load over a single tire footprint for days at a time. The right structural section under a Class-A RV pad is 3 to 4 inches of asphalt over 10 to 14 inches of compacted aggregate base on clay subgrade, with the wearing course mix specified as PG 64-22 minimum and PG 70-22 preferred for high-volume parks.
The static-load problem is what makes RV park spec different from retail parking. An apartment-complex lot can hold a parked car overnight without rutting. An RV pad sees a 40,000-pound coach parked 3 to 7 days with full weight on a four-corner footprint. Without the deeper structural section, rutting at the wheel positions is visible within the first two seasons.
1 Percent Max Cross-Slope Level-Pad Spec
RV manufacturers spec leveling jacks for a maximum cross-slope of 1 percent (roughly 1/8 inch per foot). Beyond that, slide-outs may bind, leveling jacks may not reach their stops, and the refrigerator gas-burner cycling can fault. A pad that paves to a 2 percent cross-slope -- normal for retail parking drainage -- is a failed RV pad. Drainage on a level-pad RV site is handled via longitudinal slope, not cross-slope -- shedding water to a sloped curb or swale at one end.
This is one of the most common spec failures on jobs awarded to retail-lot crews. Hillsboro owner-operators should ask the contractor for prior RV-park references and confirm the contractor has spec'd 1 percent max cross-slope on those jobs before signing.
Utility-Pedestal Trench Reinstatement
Each Hillsboro RV site has a utility pedestal carrying 50-amp electrical, 30-amp electrical, fresh water, sewer dump, and sometimes cable. Supply trenches run from the back of the pad to the pedestal location, crossing the pad perpendicular to the centerline. When the pad gets repaved, those trenches usually need utility work first -- replace old water lines, upgrade sewer cleanouts, run 50-amp upgrade conduit -- and then the trench has to be reinstated to match the pad section.
On Tualatin Plain clay subgrade, trench reinstatements need particular discipline because the clay subgrade doesn't drain. A trench that holds water through the wet season will heave and settle differently than the surrounding pad. The right detail is the same structural section, compacted in lifts, with the wearing course finish-graded to match. Our RV pad excavation guide covers the underlying excavation discipline in more depth.
Phased Work for an Active Hillsboro RV Park
Hillsboro RV parks running through the May-October window rarely shut for paving. Phased work is the standard playbook:
- Rotate guests out of one section (typically 8 to 20 sites per phase).
- Mill and pave the empty section in a 2 to 4 day cycle.
- Allow 48 to 72 hours of cure before reopening to RV traffic.
- Coordinate utility crews on any pedestal upgrades during the same phase.
- Move to the next section.
Phased work adds 15 to 25 percent over a single-mobilization job. The right scheduling for Hillsboro RV parks is March through May or mid-September through October. The Hillsboro parking lot striping work and our Hillsboro church paving project notes cover similar phased-work scheduling for related Washington County commercial sites.
Industry Baseline Range for Hillsboro RV Park Paving
Pricing depends on site count, structural section, utility-pedestal trench work, and phasing intensity.
Industry Baseline Range
| Scope | Cost Per Sq Ft | Typical Total |
|---|---|---|
| Sealcoat plus crack-fill (clean lot) | $0.20 to $0.45 | $5,000 to $25,000 |
| Mill 2 inches, repave wearing course | $4.00 to $7.00+ | $40,000 to $200,000+ |
| Full structural rebuild (multi-site) | $8.00 to $14.00+ | $120,000 to $600,000+ |
| Utility-pedestal trench reinstatement | $20 to $60 per lf | $1,000 to $8,000 per pedestal |
Current Market Reality
Hillsboro RV park paving pricing in 2026 reflects fuel surcharges of 3 to 7 percent, polymer-modified binder upcharges for parks running heavier Class-A traffic, Washington County stormwater permit costs, and the deeper-base requirement on clay subgrade. A 30-site Hillsboro RV park that priced at $4.00 per square foot for a mill-and-overlay in 2019 commonly bids $5.50 to $7.00 today after structural section upgrade. Cojo's asphalt maintenance services handle the maintenance-cycle work between major repaves.
Coordinating With KOA, Good Sam, and Franchise Standards
Branded Hillsboro RV parks under KOA, Good Sam, or other franchise umbrellas often have brand standards review on structural rebuilds. Add 10 to 30 days for franchise approval before the work scope locks. A coordination call with the owner-operator and the franchise contact confirms spec, color, and any brand-specific finish requirements.
Talk to Cojo About Your Hillsboro RV Park
If you operate a Washington County RV park with rutting at the wheel positions, slide-out binding complaints from guests, or pedestal-trench settlement on Tualatin Plain clay subgrade, the next step is a pad walk. We will measure cross-slope tolerance, document rutting patterns, walk the utility-pedestal layouts, and write a phased scope that hits the wet-season window and your occupancy calendar. To start, schedule a pad walk and we will be at the park within the week.