Detached ADU · Kuna, ID
A 376 sq ft Osprey studio on a Kuna acreage lot — a detached guest suite paired with a workshop bay, set well back from the main house with land to spare, and built with the ACHD road fee budgeted from the start.
Sited a detached Osprey studio plus a workshop bay on an open Kuna acreage parcel
Set the unit well back from the main house for guest privacy and a clean separate entry
Budgeted the ACHD road impact fee up front, since Kuna sits in the Ada County Highway District
Trenched water, sewer, and a separate electrical service across the longer utility run an acreage lot requires
Full kitchen + 3/4 bath finished to a true rental standard so the guest suite can become income later
Standard-finish interior — durable LVP, quartz counter, tile shower — with the workshop kept on its own circuit
The challenge
Kuna acreage lots are the opposite problem from a tight in-town parcel — there's room to spare. The constraint isn't the buildable envelope, it's that Kuna falls inside the Ada County Highway District, so the project carries an ACHD road impact fee that owners on smaller city lots sometimes overlook until it lands. The longer utility runs across an open parcel also add cost that's easy to underestimate. The owners wanted a guest space for family visits and a real workshop, without the whole thing reading as a second house dropped in the yard.
Our approach
The 376 sq ft Osprey gives a comfortable studio footprint, and on an acreage lot we paired it with a workshop bay without crowding anything — there was land to spare on every side. We sited it well back from the main house so guests get a private entry and the workshop noise stays away from the home. The ACHD fee went into the budget on day one rather than surfacing as a surprise, and because the plan is pre-approved it skipped the design phase. The interior was finished to a real rental spec, so the guest suite is income-ready whenever the owners want it.
The outcome
The build ran on a roughly six-month contract-to-keys timeline. Today it's a guest suite for visiting family and a working shop on its own circuit, but because it was metered and plumbed as a true dwelling, converting the studio side to a long-term rental is a tenant search, not a renovation. On a Kuna acreage lot with room to spare, it's a flexible use of land that holds its value either way.
"We had the room, we just didn't want a second house plopped in the yard. The Osprey set way back works as a guest place and gave me a real shop, and the builder had the ACHD fee in the number from the start so nothing snuck up on us."
Travis & Renee K.
Kuna, Ada County
City
Zoning, plans, and local fit for Kuna ADU builds.
Cost
Real 2026 pricing by plan and finish for this market.
Plan
Sister plan to the Sandpiper — 376 sq ft studio with garage, a different layout, same pre-approved status.
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