Scappoose sits on Highway 30 between the Portland metro and St. Helens, with Scappoose Creek through town and the Columbia a few miles east. The City of Scappoose and unincorporated Columbia County are separate reviewers. A West Lane address and a two-acre parcel toward Warren can share a mailing city and still file in different systems.
Wolf builds in Battle Ground, across the Columbia in Clark County, and delivery comes through Portland on I-5 / I-205, then out Highway 30. We don’t have a recorded Wolf delivery in Scappoose yet, but the city is inside our Washington-and-Oregon turn-key area, and we review lots here the same way we do in St. Helens and the rest of the county.
City of Scappoose or Columbia County first
Pull the parcel before you sketch a backyard. If the lot is inside city limits, the city’s Planning and Building staff review it under Title 17. If it isn’t, county land-use rules apply even when the mail says Scappoose. Warren is unincorporated, and Columbia City is a separate incorporated city. Lots toward Warren can look like county pasture and still be in the city, or the reverse, so check GIS first.
Oregon cities over 2,500 must allow at least one ADU on qualifying single-family lots inside a UGB (ORS 197A.425). HB 2001 blocked owner-occupancy and extra off-street parking mandates for long-term units. We also check the city’s requirements for your property. Read the Oregon ADU rules guide and the Columbia County ADU rules guide.
Inside Scappoose, accessory dwelling units live in Chapter 17.92. The standards we use on evaluations (confirm the current section when you file):
- An ADU is allowed only in conjunction with a parcel that already has one single-family dwelling. Only one ADU per parcel.
- The unit may be a conversion, an addition, or a new attached or detached structure. An attached garage doesn’t count as living area for a conversion.
- Size: gross habitable floor area shall not exceed 50 percent of the GHFA of the primary residence, and shall not exceed 800 square feet, whichever is less. Garage floor area is excluded from that total.
- Design notes in the chapter have addressed front-entrance location and, in some cases, buffering of a detached unit from neighbors.
- Older 17.92 text also included owner-occupancy language and an extra on-site parking space if the primary dwelling had fewer than four spaces. Statewide law blocked those mandates for long-term ADUs. Confirm what the current chapter still requires, and don’t assume an ADU permit allows a vacation rental.
If a number isn’t in current 17.92 or in the current handout, it depends on the lot. Ask with the address.
The county’s ADU packet includes a chart with different size and owner-occupancy notes for Columbia City, Clatskanie, Rainier, Scappoose, Saint Helens, and Vernonia. A Scappoose city ADU and a rural Columbia County ADU should not be priced from the same assumptions.
Unincorporated Columbia County has its own rules. Ordinance 2023-1 is the rural residential path: at least two acres; 900 square feet of usable floor area; one ADU; no farther than 100 feet from the primary dwelling. Water, wastewater, road access, and a fire protection district are screening items. The ADU may not be used for vacation occupancy. A rural ADU approval can’t be used to justify a partition. The city’s 800 / 50 percent test doesn’t apply on a rural lot, and the county’s two-acre rule doesn’t apply on a city lot.
Scappoose Creek floodplain lots fall under a separate overlay, and some R-4 and other district standards change inside the floodplain. Check the map before treating a creek-adjacent backyard as a simple pad.
How Scappoose handles a permit
A complete Scappoose file gets a review date, while files with incomplete site plans, missing floodplain sheets, or no truck path wait. Here’s the path we use:
- Confirm a dwelling is allowed in this zone, using city maps plus Chapter 17.92. The city’s own building page points people to the zone chapter (for example R-4 dimensional standards) and to 17.92 for ADUs.
- Draw the plot plan: existing house, proposed cottage, setbacks for that zone, parking, utilities, floodplain lines if they apply, and a truck path that works on Highway 30 or a West Lane driveway.
- Prepare the engineered modular plan set. Wolf homes are modular, built in Battle Ground under Oregon’s BCD prefabricated-structures program, delivered with a state insignia of compliance, and placed on a local foundation. They aren’t HUD (the federal standard for manufactured homes) manufactured homes and they aren’t on wheels. Scappoose still reviews the foundation, placement, utilities, and the 17.92 siting standards.
- Submit to the city (or Columbia County Land Development Services if unincorporated). Include how water and wastewater will be handled. Site prep is part of the job.
- Complete inspections as called, then get occupancy. Keep approved drawings on site.
County rural files add the two-acre, 100-foot, 900-square-foot, septic, and fire-district checks before a floor plan can be chosen. The county asks applicants to talk to the Planner On Duty and to submit a detailed site plan.
A city submittal usually includes the application, a site plan with property lines and setbacks, floor plans, how water and wastewater will be handled, and any 17.92 design sheets. Oregon BCD inspects the module in the factory, and Scappoose inspects the foundation, placement, and utility connections.
If the lot is outside city limits, Ordinance 2023-1 and the zone’s own chapter are the starting point. A parcel can pass two acres and 100 feet and still fail on septic, access, or a resource-zone setback.
Scappoose lots
Downtown Scappoose is a Highway 30 town with a real main street, older houses, and a creek that shows up on the maps. Downtown and the older blocks off Highway 30 / Columbia Avenue can be tight, with short lots, on-street parking, and a main street that wasn’t laid out for a module. Westside plats off West Lane are often wider and HOA (homeowners association)-controlled, and they still have tree and drainage questions and fall under the 800 / 50 percent test. Toward Warren, city and county parcels are mixed together. Creek-adjacent lots add floodplain and setback questions that dry upland lots don’t have.
Delivery from Battle Ground takes half a day when the last mile is clear. A 12-foot-wide Model K and a 14-foot Model E face very different access on a street with parking on both sides, and overhead lines, firs, and a driveway built for a passenger car still decide how set day goes.
Models that fit 800 / 50 percent
Wolf doesn’t sell HUD-code manufactured homes, and a unit on wheels doesn’t qualify as an ADU here.
- Model K (~432 sq ft). One-bedroom ADU on a typical city lot.
- Model E / Model F (~616 sq ft). Two bedrooms when 50 percent of the primary dwelling still allows it.
If the house has 1,200 square feet of GHFA, 50 percent is 600, so measure first. Model J (~828 sq ft) is over the city’s 800 cap as published. County rural lots use the county’s 900 square feet of usable floor area, not Scappoose’s 800.
ADU, tiny home, or granny flat
If it has a kitchen and a bath, the city treats it as a dwelling. Family occupancy and long-term rental are the usual uses, and short-term lodging is a separate local question. Columbia County prohibits vacation occupancy of the ADU on county lots. Tell us the use on the evaluation.
“Tiny home,” “granny flat,” and “ADU” sound like different products, but they’re the same dwelling under Chapter 17.92, with the same file and the same factory insignia.
Cost and timeline
The model gives us a reliable starting home price. We price trenching, electrical capacity, floodplain or drainage work, and any required buffering after reviewing the property. Factory construction protects the home from lower Columbia rain, while city or county review and site preparation still affect the schedule.
The Model K starts at $85,500 for the home itself. Permitting, delivery, installation, and site work are listed separately in your property-specific proposal. Scappoose does not offer the same ADU SDC waiver as Salem, so we confirm current fees for your property before preparing the proposal. See financing.
A West Lane backyard and a Warren-area acre won’t cost the same. We quote after a property evaluation.
What to send
An address is enough to start. Useful extras include a survey, tax-lot and zoning printout, square footage of the existing house (needed for the 50 percent test), floodplain information if you have it, photos of the backyard and the street approach, and whether the use is family, long-term rental, or a cottage you might occupy. We check city versus county, the size cap, floodplain, utilities, and whether a truck can reach the pad.
If you’ve already picked a model, we still check it against 800 square feet and 50 percent of primary GHFA (or the county’s 900) before treating it as the plan.
Turn-key service and nearby cities
This is turn-key Oregon work: permitting support, site work, production, delivery, and setup as one job. The field crew that set the home comes back for the punch list, driving from Battle Ground through Portland and out Highway 30.
St. Helens is the next city north and has its own development code. Columbia City, Rainier, Clatskanie, and Vernonia have their own city halls in Columbia County. Portland is in a different county with different SDCs.
Climate, soils, and utilities
The lower Columbia is wet from fall through spring. The house is built indoors. On the lot, silts, winter water, and creek-adjacent water tables change excavation and erosion control. Summer is the easier set window, and winter sets need tighter site control.
Most in-city lots are on city water and sewer. That still leaves laterals, a cleanout, and whether the electrical service can handle a second dwelling. Outside city limits, lots are often on a well and septic, and rural ADU rules plus septic design usually decide those parcels. If you don’t know which applies to your lot, that’s the first thing we check.
Highway 30 through Scappoose is the usual last mile from I-5 / I-205. Weekend river traffic, school pickup, and a narrow approach off the highway all affect when a module can roll. We plan the delivery around them.
Site work
Foundation excavation, trenching, grading, and minor tree work so the home can sit are part of a normal Scappoose job. A downtown curb that looks like a delivery path, or a West Lane driveway built for a passenger car, is why we measure access early.
A standard delivery trailer, and a crane when the swing needs it, get the home onto the foundation. We weather-seal the same day when we can, then handle the mechanical and plumbing tie-ins. Two-piece plans add a day to join the halves. On-street parking along 30 goes on the schedule too.
Financing is usually a HELOC, a cash-out refinance, or a construction-to-permanent lender familiar with factory-built ADUs. Oregon SDCs and local connection fees belong in the proposal. See financing.
After the set
Next come inspections, a walk-through, the punch list, keys, and warranty. Scappoose inspectors control occupancy on city lots, so keep the approved drawings on site until they sign off.
If you already have a survey or a prior planning letter, send it. An address and a sense of where the building would sit is enough to start. If the lot can’t fit a home under the 800-square-foot cap or can’t take a truck, we’ll tell you before you pick a floor plan.
Send the address. Tell us city or county, where the building would sit, and how you’ll use it, and we’ll match a model to the cap that applies.
