Gresham is in east Multnomah County, close to our Battle Ground factory. Delivery is a local run across the river and out I-84 or Powell Boulevard. Permits here go to the City of Gresham instead of Portland’s DevHub. Wolf has built ADUs in the Gresham area.
The city describes an ADU as a second unit on a single-family residential property. It works as a complete, independent living space with its own kitchen, bathroom, and sleeping area. ADUs are regulated under the Gresham Community Development Code, Section 10.0100.
That section is separate from Portland’s Title 33, so Portland’s 800 sq ft cap doesn’t apply in Powell Valley. Gresham’s online SDC calculator and Urban Design and Planning handouts are useful public tools.
We still walk the lot. A calculator can’t tell you whether a cedar or a low service drop blocks the set. It also can’t tell you whether the lot is in Pleasant Valley, Springwater, or an older infill block with a different parks SDC.
How Gresham regulates ADUs
Section 10.0100 is the starting point, and we use its current code language on evaluations. The size standard reads: “accessory dwellings shall have a maximum floor area of 900 square feet or 75 percent of the floor area of the primary dwelling, whichever is less.”
That’s larger than Portland’s typical 800 cap. So a Model J (~828 sq ft published) can work in Gresham when the house is big enough that 75 percent isn’t the limiting number.
The city’s ADU handout has described different review types by how the unit is built. Those include a conversion, an attached unit, one beside or behind a garage, or a freestanding unit, with Type I and Type II paths. Older handout language listed smaller caps for some garage-side and freestanding setups, including a 750 sq ft figure.
When the two disagree, the code section governs, so we read both against your plan. Our Oregon ADU rules guide covers the state side. We’ll check the local numbers for your lot once you send the address.
Other 10.0100 points that come up on evaluations:
- In several listed low-density districts, ADUs don’t count toward minimum or maximum density. Other districts treat them differently for minimum density, so the zone matters.
- Existing legal accessory structures that are nonconforming on setbacks have a conversion path with a date trigger in the code. Nonconforming means the building was legal when built but doesn’t meet today’s setbacks. That path covers conversions only. It doesn’t cover a new modular home.
- The code addresses short-term rental use, so don’t assume Airbnb. Long-term rental is broadly allowed under state law.
At the state level, ORS 197A.425 applies. There’s no rule that the owner has to live on site. Under HB 2001, long-term units also don’t need extra off-street parking. Gresham still sets siting, the 900 / 75 percent test, design standards where the handout requires them, and SDCs.
Unincorporated Multnomah County lots in east county with a Gresham mailing address don’t go through Urban Design and Planning. County land use is a separate counter. Troutdale and Fairview have their own city halls. If CMAP or Multnomah GIS shows the lot as unincorporated, the Gresham process doesn’t apply.
Models that fit 900 or 75 percent
Wolf doesn’t sell HUD code (the federal standard for manufactured homes) manufactured homes. Our homes are modular dwellings under Oregon’s BCD prefabricated-structures program. Each one sits on a local foundation under a city installation permit. They leave Battle Ground with the Oregon insignia, and Gresham still inspects the foundation, the set, and the utilities.
- Model K (~432 sq ft). A one-bedroom ADU when you want a real bedroom and bath.
- Model J (~828 sq ft). A larger two-bedroom when the house is big enough that 75 percent allows it and the lot can take a two-piece set. Model E / Model F (~616 sq ft) fit comfortably under both 900 and a typical 75 percent test.
If the house is 1,000 sq ft, 75 percent is 750, and the Model J is too big. We check every plan against the main house’s actual floor area.
Permits: Gresham’s portal
Gresham Urban Design and Planning publishes ADU information and application materials. You submit through Gresham’s online portal. The handout path goes roughly like this:
- A development-permit application and narrative.
- A site plan showing structures, water and sewer lines, property lines, driveways, and trees.
- A preliminary floor plan.
- Building features: height, materials, roof pitch, windows, and door orientation.
If that’s approved, building permits go through the same portal.
Type I versus Type II depends on how the ADU is created. A Wolf home is a freestanding new cottage, which gets reviewed differently from a basement conversion. Incomplete tree plans and missing sewer laterals on the site plan are the most common reasons Gresham sends a file back. Our permit team puts together a complete packet, because that’s what keeps Gresham’s review moving.
Our process starts with feasibility work. That covers city versus Multnomah County versus Troutdale or Fairview, the 900 / 75 percent test, trees, utilities, and the truck path. It also covers whether the map puts the lot in Pleasant Valley or Springwater. Then comes a scoped proposal, and then the portal submittal.
System development charges
System development charges (SDCs) are one-time fees that help pay for public systems. The city’s ADU materials are clear: ADUs are charged System Development Charges. Transportation and parks are called out on the handout, and new paving or structures may trigger more. Contact Development Engineering or use the city’s online SDC calculator.
Water, wastewater, and stormwater SDCs are separate city programs. Their resolutions have been updated on a July cycle in recent years. Parks and stormwater SDCs are higher in Pleasant Valley and Springwater, the newer urban-growth areas, because extending facilities there costs more. A Kelly Creek or Pleasant Valley lot pays different fees than a downtown Gresham infill lot.
As far as we know, Gresham hasn’t eliminated ADU SDCs the way Salem did. It also doesn’t have a citywide ADU waiver covenant like Portland’s 10-year program. We run the calculator for your lot.
Where Gresham lots run into trouble
East county has a wide range of backyards.
- Rockwood and the MAX corridor. Inner-ring lots with older laterals and tighter streets. These usually point to a Model K over a J.
- Downtown Gresham and the historic grid. Delivery looks fine until Main Street parking and trees block the crane path.
- Powell Valley, Kelly Creek, and Hogan. More suburban lots with longer laterals and sometimes easier trucking. Some fall under the Pleasant Valley fee overlay.
- Springwater. A newer UGB area with higher parks and storm SDCs and different infrastructure.
- Slopes toward the Sandy River canyon. Orient, some north-edge lots, and anything that starts to look like Troutdale need a grade and drainage review.
- Trees. The portal packet asks which trees stay and which go, so plan for it.
How people use these homes
Gresham ADUs serve as family housing, aging-in-place cottages, long-term rentals, and guest space. East-county jobs and Portland rents keep rental demand strong. The short-term rules in 10.0100 are why we ask about the intended use on day one.
A mother-in-law unit or backyard cottage with a kitchen, bath, and sleeping area is an accessory dwelling under Section 10.0100, whatever you call it. It gets the same 900 / 75 percent test and goes through the same portal. The code deals with how it’s used (family, a long-term tenant, or short-term guests) on its own terms.
For nearby examples, see our completed projects in Portland and Milwaukie.
Factory build and east-county set days
Once Gresham issues the permit, we build the home in Battle Ground while site work moves forward. Delivery usually comes down I-205, across the Glenn Jackson Bridge, and out I-84. That’s closer than Hillsboro, and a different route than an inner-east Portland crane job. Set day is the day the home is placed on its foundation. We weather-seal it the same day, and two-piece J plans add a day to join the halves.
Gresham gets Portland-metro rain, with slightly bigger temperature swings on the east edge. Winter soils still decide when we can dig. Powell Valley clay and a Springwater lot that was pasture five years ago need different foundation designs. We plan foundation work around the forecast.
Utilities
Gresham water, wastewater, and storm are city programs with their own SDCs. Power is typically PGE or Pacific Power, depending on the area, since east county doesn’t have a single provider. Rockwood laterals and a Pleasant Valley lot waiting on a new main lead to very different bids.
What goes into a Gresham proposal
Your model sets the starting home price, and we price site work once we’ve seen the property. Trench length, electrical upgrades, and SDCs can make the total differ between two lots with the same model. That’s especially true in Pleasant Valley and Springwater. Local development and engineering charges still apply. Our financing page covers ways to pay.
Neighboring cities and counties write their own rules. Troutdale and Fairview are separate cities. Happy Valley is in Clackamas County. Portland uses DevHub and an 800 sq ft cap. Rockwood, downtown, Powell Valley, and Springwater are all Gresham, but each has its own fees and site conditions.
After the set
Next come inspections, a walk-through, the punch list, keys, and the warranty packet. Your home comes with a one-year warranty, and we stand behind our workmanship for years afterward. Gresham is a short run from Battle Ground compared with Salem or Corvallis. So punch-list trips are routine field work, and a missing piece of trim gets fixed quickly.
What a Gresham evaluation looks at
Bring the address and a backyard sketch. A Gresham portal login, a prior addition permit, or an SDC calculator printout helps if you have one. An address and a guess at the house’s floor area are enough to start.
The free property evaluation is our first look at zoning, setbacks, and what’s generally allowed. For a Gresham lot, it covers:
- City of Gresham versus Multnomah County versus Troutdale or Fairview.
- The main house’s floor area, for the 900 / 75 percent test, and whether a Model J fits.
- Whether the site is in Pleasant Valley or Springwater for SDC purposes.
- The Type I or Type II path for a freestanding modular unit under the current handout.
- Short-term versus long-term use under 10.0100.
The deeper site checks come next, as the project moves forward. Paid work starts only after a signed agreement. Those checks include:
- Trees, laterals, panel, and meter.
- The truck path from I-84, Powell, or Highway 26 to the curb.
The 900 / 75 percent test and the Pleasant Valley fee overlay are the two numbers most likely to change the model. Tell us how big the house is and if you’re in Pleasant Valley. We’ll match a model to Section 10.0100. Send the address to get started.
