ADU & Small House Plans · Idaho
ADU and Small House Plans in Idaho
Looking to buy ADU and small house plans in Idaho? HousePlans USA draws ADU and small house plans from scratch for Idaho. Two or more designers sketch concepts for your lot, you pick your favorite, and permit-ready plans arrive in as little as 24 hours.
From $1,050 · free customization · 30 days of free revisions · pay 75% to start
Why buy ADU and small house plans for Idaho from us
Small homes work harder than big ones: every foot has to earn its place. A backyard ADU can house a parent, earn rent or become a home office.
We draw studios, one- and two-bedroom cottages, garage apartments and affordable starter homes to your city's size, height, setback and parking rules.
ADU rules handled
Size, height, setback and parking limits are checked for your lot before concepts begin.
Live large in less
Vaulted ceilings, lofts and built-in storage make small rooms feel open.
Build it again
PDF unlimited build rights for $395 let you reuse the plan on more lots.
What's included in your ADU and small house plans
- Studio, 1-bedroom and 2-bedroom layouts
- Garage apartment with fire separation details
- Utility routing from the main house
- Aging-in-place details on request
- Unlimited-build rights available for investors
Plan prices by size
| Up to 1,000 sq ft | $1,050 |
| 1,001 – 1,500 sq ft | $1,295 |
| 1,501 – 2,000 sq ft | $1,495 |
| 2,001 – 2,500 sq ft | $1,695 |
| 2,501 – 3,000 sq ft | $1,895 |
| 3,001 – 3,500 sq ft | $2,195 |
Idaho engineer stamp from $1,000. See every option on our pricing page.
Building requirements
Building a house in Idaho, ID: what the code requires
Statewide residential code
- Building code
- Idaho adopts the IRC statewide, but local jurisdictions enforce it and some rural areas have no inspections.
- Energy code
- Idaho Residential Energy Code (IECC-based with amendments) applies statewide.
- Climate zone
- IECC climate zone 5–6. Insulation, windows and HVAC are sized to match.
- Typical frost depth
- 24–36 in. Footings must extend below the local frost line (confirm with your building department).
- Foundations
- Full or walkout basements are common thanks to deep frost lines.
- Who can draw the plans
- Single-family homes can generally be designed by a non-licensed home designer. A licensed engineer's stamp is often required for structural items, engineered foundations or special hazard zones, or when the local building official asks for it.
- Engineer stamp
- If your jurisdiction requires sealed drawings, add our Idaho Engineer Stamp / Permit-Ready package ($1,000).
Idaho-specific rules & hazards
- Northern Idaho has high snow loads, and some areas face wildfire risk.
- Heavy roof snow loads and steeper, well-braced roof framing
- Wildfire-resistant materials and defensible-space detailing
- Seismic bracing, shear walls and hold-downs
Summary for planning only. Codes, editions and local amendments change, so always confirm current requirements with the building department that will issue your permit. Our designers check your jurisdiction before drawing.
Cottage homes we can draw for Idaho
Style inspiration photos, not homes built in Idaho or by HousePlans USA.
How ordering works
- 1
Get inspired
Pick the exterior styles and interior looks you love, or paste links to plans you've seen online.
- 2
Design & instruct
Choose rooms, size, basement, garage and your state, and tell our designers exactly what you want.
- 3
Compare 2+ concepts
Two or more designers each sketch a concept. Pick your favorite designer to draw the full plans.
- 4
Download & revise
Plans arrive by email and in your dashboard by your deadline. Revisions are free for 30 days.
ADU and Small House Plans in Idaho: FAQ
Can I build an ADU in Idaho?+
In many cities, yes, but size, setback and parking rules vary. We check your lot's rules before we sketch.
Do you draw garage apartments?+
Yes. We draw one- and two-bedroom apartments over garages, including the required fire separation.
How much do ADU and small house plans cost in Idaho?+
Custom plans start at $1,050 for homes up to 1,000 sq ft and are priced by size. Most family homes come to $2,000–$3,000 all-in, with free customization and 30 days of revisions.
How fast can I get ADU and small house plans for Idaho?+
Standard delivery is 10 business days. Priority, Express, Rush (48 hours) and Super Rush (24 hours, up to 3,000 sq ft) are available at checkout.
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Let's design your home for Idaho
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