Barndominium Floor Plans with Garage in Oregon

An attached garage is the easiest upgrade a barndominium offers: the same clear-span frame that covers the house covers two, three or four bays, under one roofline, with no separate building to permit. Oregon owners use the space for vehicles, a workbench, a freezer and, on rural land, the tractor. The plan decisions are the wall between garage and house, the floor, whether the garage is heated, and whether anyone will ever live above it.

Start your project

What actually changes with this feature

The look is the easy part. These are the decisions that follow from it.

Bay count and door size

Two bays is the minimum most rural owners regret; three gives room for a truck, a car and a workbench, and a deeper third bay takes a boat or a side-by-side. Size the doors to the tallest vehicle with a rack, and give each bay enough depth to walk around a full-size pickup with the door closed.

A floor that drains toward the door

ORSC Section R309.1 requires garage floors of approved noncombustible material, with the area used for parking sloped to move liquids to a drain or toward the main vehicle entry. In winter rain or snowmelt, that slope decides where a wet truck's water goes. If you want an interior floor drain, settle where it discharges before the slab is poured; it does not belong in a septic system.

Heated or unheated

An attached garage is normally left outside the insulated envelope, with the separation wall insulated like an exterior wall. A heated or cooled detached garage that is not habitable has its own, shorter envelope list in the ORSC energy chapter, with no additional energy measure required. The ORSC energy chapter sets the insulation and window values for the edition your permit is reviewed under.

An apartment over the garage

A bonus room above the garage is part of the house; a second dwelling up there is a land-use question. On rural residential land ORS 215.495 lets a county allow one accessory dwelling unit up to 900 square feet of usable floor area, within 100 feet of the existing house, on a parcel of at least two acres, among other conditions. Oregon's onsite rules define an accessory dwelling unit as having no more than two bedrooms. Ask the county first.

The garage wall

The ORSC sets what separates the garage from the house

Under the 2023 Oregon Residential Specialty Code, Table R302.6 requires at least 1/2-inch gypsum board or equivalent on the garage side of the wall between the garage and the residence and its attic, and at least 5/8-inch Type X gypsum board or equivalent where habitable rooms sit above the garage. Walls and structure supporting that floor need at least 1/2-inch gypsum board. Section R302.5.1 bars any opening from the garage directly into a room used for sleeping, and other openings need a solid wood door or a solid or honeycomb-core steel door at least 1-3/8 inches thick, or a 20-minute fire-rated door. In a barndominium the garage wall is usually an interior wall inside one steel shell, so it is easy to get right on paper and easy to miss on site.

Common ways to build this

Three common ways to lay this out. Yours does not have to match one exactly — this is a starting point for the conversation, not a catalog.

Two-bay attached garage

1,800 sq ft living / 600 sq ft garage (24' x 25')

A two-car garage at one end of the house, entered through a mudroom and laundry. The separation wall carries gypsum on the garage side and insulation in the cavity, and the door into the house is solid-core and self-closing by choice.

Three-bay garage with a deep bay

2,000 sq ft living / 1,000 sq ft garage (40' x 25', one bay 35' deep)

Three doors along the gable end, with the third bay extended for a boat or trailer. A workbench runs along the back wall and a freezer sits on its own circuit.

Garage with a bonus room above

1,800 sq ft living / 720 sq ft garage / 500 sq ft bonus room above

The bonus room over the garage is reached from inside the house, with 5/8-inch Type X gypsum board on the garage ceiling below it. Kept as part of the house, it needs no separate land-use approval; fitted out as an apartment, it does.

Ways to build this

This layout can go together several ways. These are the service lines most relevant to it.

Custom Plans

Custom barndominium plans drawn for Oregon's residential code, your site's snow and seismic values, and the energy chapter a steel shell must meet.

Shouses

Shop houses in Oregon: a working shop and a home under one roof, planned around your zoning, septic and the residential code from the first sketch.

Steel Construction

Red-iron steel frames and metal building shells erected across Oregon, sized to your site's snow, wind and seismic values and built to live in.

Barndominium Kits

Barndominium kits and shell kits for Oregon land, sized to the snow, wind and seismic values the state's design hub gives for your exact site.

Barndominium with a Garage: common questions

6 questions worth settling before this plan is drawn. If yours is not on the list, put it in the survey.

Start your project

What fire separation does an attached garage need in Oregon?

Under the 2023 ORSC: at least 1/2-inch gypsum board on the garage side of the wall separating it from the house and attic, 5/8-inch Type X gypsum board under habitable rooms above, no opening into a sleeping room, and a solid wood, solid or honeycomb-core steel, or 20-minute fire-rated door between garage and house.

Can a bedroom door open into the garage?

No. ORSC Section R302.5.1 does not permit openings from a private garage directly into a room used for sleeping.

Does the garage floor have to slope?

Yes. ORSC Section R309.1 requires the parking area to be sloped so liquids move to a drain or toward the main vehicle entry, and the floor must be an approved noncombustible material.

Can I build an apartment above the garage?

A bonus room that is part of the house is straightforward. A separate dwelling depends on the zone: on rural residential land ORS 215.495 lets a county allow one accessory dwelling unit under set conditions, including a 900-square-foot cap on usable floor area; farm and forest zones are stricter. Inside city limits, the city's own rules apply.

Should the garage be heated?

For a workshop, many owners heat it. If it is attached, keep the separation wall insulated. A heated detached garage that is not habitable follows its own envelope list in the ORSC energy chapter, covering walls, roof, windows, doors and roll-up doors, for the edition your permit is reviewed under.

Is a garage the same as a shop?

Not always. Under ORSC Section R309.2 a carport must be open on at least two sides, and one that is not is considered a garage. An attached workshop is commonly reviewed under the same garage separation rules, so ask the building department how it will treat yours. A shop used as a place of business also raises zoning questions a garage does not.

Want this drawn for your program and your parcel? That is where a build actually starts.

Start your build survey

Sources

Code figures on this page are from the 2023 Oregon Residential Specialty Code. The Building Codes Division anticipates a 2026 edition from October 1, 2026, with a six-month phase-in; the edition your permit is reviewed under governs.

Start your plans

Tell us what you want to build and we will draw this for your program, then confirm what it looks like on your parcel, which office permits it, and a realistic budget range. That conversation costs nothing.

Start your project