Forest Grove ADU Builder

Building an ADU in Forest Grove begins with what your lot allows

An accessory dwelling unit is a complete small home (kitchen, bath, sleeping space, its own entrance) on the same property as your house. Because it is a dwelling, the first answers come from the zoning rules and the utility layout, and only then from a floor plan. JDI Construction is a family-owned design-build remodeler, and when a Forest Grove homeowner asks us about an ADU we start by checking the property against the City of Forest Grove development code, or against Washington County's rules if the land is outside city limits. That tells you what is possible before you spend money on drawings.

One team handles the feasibility review, the design and the construction, so the plan you see has already been tested against the site. We would much prefer to tell you early that a detached unit will not fit than to discover it at the permit counter.

The work that makes an ADU succeed

Four pieces of work, in this order, carry an ADU from idea to occupancy:

1. 1
   

   Feasibility firstA check of zoning, setbacks and site constraints for your parcel, done ahead of any design work.
2. 2
   

   Site & utilitiesAccess for construction, drainage, and the route for sewer, water and electrical service to the new unit.
3. 3
   

   Designing for smallDaylight from more than one side, built-in storage and higher ceilings, so a compact plan feels comfortable.
4. 4
   

   PermittingApplications, plan review responses and inspections for a new dwelling, managed by our team.

Three things to pin down first

Begin with what kind of unit suits the property. Converting a garage reuses a structure you already have. An attached unit shares a wall and often utilities with the main house. A detached cottage gives the most privacy and asks the most of the site. Then be specific about who will live there, because a unit for a parent should be on one level with a step-free entry and a roomy bathroom, while a rental needs durable finishes and a private approach from the street. Last, set aside budget for work you will never see: trenching and connecting sewer, water and power, and the fees a jurisdiction charges for adding a dwelling. We identify those items during the feasibility stage so they are part of the first number you see.

What Forest Grove homeowners build ADUs for

Forest Grove is a university town, home to Pacific University, with long-established neighborhoods and farmland close by. The uses we would expect on properties like these are familiar ones: a small house for a parent who wants independence with help close at hand, a place for an adult child, a long-term rental, or a studio or office separate from the main house. Each one changes the design brief, so we ask about use before we ask about style.

The property matters as much as the purpose. Inside the Clark, Painter's Woods and Walker-Naylor historic districts, the city's Historic Landmarks Board reviews new construction and exterior alterations, so a detached unit there needs to take its cues from the main house in roof form, siding and proportion, and a garage conversion has to respect the existing exterior. In the subdivisions built since the mid-twentieth century, the limiting factor is more often rear-yard depth and setbacks, which can favor an attached unit. On acreage outside the city, Washington County is the reviewing jurisdiction, and the capacity of an existing septic system or well may decide what can be added. We sort out which of these situations applies to you at the first visit.

What does an ADU cost in Forest Grove?

Type comes first: a conversion that keeps an existing shell usually costs less than a new detached building with its own foundation and roof. Size and finish level follow. Then comes site work, which owners tend to underestimate, including utility connections, grading, access and jurisdictional fees. Matching the materials of a historic main house can add cost as well. After the feasibility check we give you an itemized estimate based on your lot and the unit type that fits it, not on a regional average.

How long does an ADU take to build?

Think of an ADU as three stages. Feasibility and design come first. Review and permitting come second, and for a new dwelling that stage generally takes longer than it does for an interior remodel, with historic review added if your property is in a district. Construction is third, and a conversion goes faster than a ground-up cottage. In Forest Grove the city handles building, plumbing and mechanical permits, and Washington County handles electrical. We manage every submittal and keep the schedule current in our client portal.

Why Forest Grove homeowners hire JDI

ADU projects stall when the people drawing the unit and the people answering the permit reviewer are not the same people. With JDI they are: one accountable team from feasibility through final inspection, licensed in Oregon, with a 5-year workmanship warranty on the finished unit. You should also know that we are based in Vancouver, WA, and Forest Grove is on the far side of the metro from us. We take on projects there, we travel for them, and we schedule accordingly so the distance is our problem to manage and not yours.

JDI Construction. "Built by family. Trusted by neighbors." Design-build remodeling and ADU construction, family-owned and based in Vancouver, WA since 2007, serving Forest Grove, Cornelius and Gales Creek.