ADU Construction Cost in Meridian
Understand the major budget considerations for ADU Construction in Meridian, including site work, utilities, and finish level.
Typical range: $80,000 – $300,000+
Most Meridian projects: $120,000–$200,000
The cost of adu construction in Meridian depends on the scope of work, materials selected, complexity of the layout, condition of existing systems, and the finish level you choose. Every project is different, but understanding the major cost drivers helps you plan a realistic budget and make informed decisions about where to invest and where to save. The ranges above reflect the full spectrum of projects we complete in Meridian — from straightforward updates to comprehensive renovations with premium materials and significant structural changes.
These are the factors that have the biggest impact on your adu builder budget in Meridian. Understanding each one helps you make better decisions during the planning phase.
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ADU Type (Detached vs. Conversion)
high impactA detached new-construction ADU costs significantly more than a garage conversion because it requires a new foundation, full framing, roofing, and all-new utility connections. Garage conversions leverage the existing structure.
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Size (Square Footage)
high impactADUs range from 300 sq ft studios to 1,000+ sq ft two-bedroom units. Larger units cost more but provide more rental income potential and livability.
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Utility Connections
high impactConnecting water, sewer, electrical, and gas to the ADU site involves trenching, new service lines, and potentially utility upgrades. Distance from the main house to the ADU affects cost.
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Kitchen and Bathroom Complexity
medium impactEvery ADU needs at least a bathroom and kitchen. The finish level — basic vs. mid-range vs. premium — significantly affects the mechanical and finish costs.
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Site Conditions and Access
medium impactSloped lots, limited access for equipment, rocky soil, or mature trees in the building area can increase site preparation and foundation costs.
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Permitting and Impact Fees
medium impactADU permit fees, impact fees, and utility connection fees vary by jurisdiction. Some Boise-area jurisdictions have reduced or waived impact fees for ADUs to encourage construction.
Materials are one of the most controllable parts of your budget. Here is how popular options compare for adu builder in Meridian:
| Material | Price Range | Best For |
|---|---|---|
| Concrete Slab or Stem Wall Foundation | $8,000–$20,000 | Detached ADU new construction |
| Standard Wood Framing | $12–$22 per sq ft framed | All ADU types |
| Mini-Split HVAC System | $3,500–$7,000 installed | Detached ADUs and garage conversions |
| Compact Kitchen Package | $5,000–$15,000 complete | Studio and one-bedroom ADUs |
| Matching or Complementary Siding | $5–$15 per sq ft installed | Seamless property aesthetic |
Concrete Slab or Stem Wall Foundation
$8,000–$20,000
Standard Wood Framing
$12–$22 per sq ft framed
Mini-Split HVAC System
$3,500–$7,000 installed
Compact Kitchen Package
$5,000–$15,000 complete
Matching or Complementary Siding
$5–$15 per sq ft installedMeridian's real estate market has grown dramatically, with median home values rising alongside Boise's. The city's family-friendly reputation and strong school district make it one of the most desirable markets in Idaho. Homeowners who remodel in Meridian see strong returns — updated kitchens and bathrooms are the top features buyers look for in this market.
Labor costs in Ada County reflect the local construction market, trade availability, and seasonal demand. Spring and summer are the busiest seasons for remodeling in the Treasure Valley, which can affect scheduling and occasionally pricing. Planning your project during the fall or winter months may provide more scheduling flexibility.
The most reliable way to understand what your specific adu builder will cost in Meridian is to schedule an in-home consultation. During this visit, we measure the space, discuss your goals and material preferences, evaluate existing conditions, and prepare a detailed scope and estimate based on your specific project.
What to have ready for your estimate consultation:
- ✓ A general idea of your budget range
- ✓ Examples of styles and finishes you like (photos, Pinterest boards, etc.)
- ✓ Any known issues with the current space (leaks, mold, outdated systems)
- ✓ A list of must-haves vs nice-to-haves for the finished project
- ✓ Your preferred timeline for starting and completing the work
●Detached vs garage conversion costs
●Foundation and site work pricing
●Utility connection costs
●Kitchen and bathroom costs
●Permit and impact fees
●Financing options for ADU construction
●ROI and rental income potential
The specific type of adu builder project affects the budget significantly. Here are the most common project types in Meridian:
Detached ADU (New Construction)
A standalone structure built on your property — typically 400-1,000 square feet with a bedroom, bathroom, kitchen, and living area. This is the most popular ADU type and offers the most design flexibility.
Garage Conversion ADU
Convert an existing attached or detached garage into a living space. Includes insulation, drywall, flooring, plumbing, electrical, HVAC, kitchen, and bathroom installation within the existing structure.
Attached ADU Addition
Build an ADU that shares one or more walls with the main home but has its own entrance, kitchen, bathroom, and living space. Similar to a home addition but designed as an independent unit.
Basement ADU Conversion
Convert an existing basement into a separate dwelling unit with its own entrance, kitchen, bathroom, and living area. Requires egress windows, fire separation, and independent utility metering in most jurisdictions.
Meridian is Idaho's fastest-growing city and the second-largest in the state. The majority of Meridian's housing stock was built after 1990, with massive subdivision development through the 2000s, 2010s, and continuing today. This means most Meridian homeowners are dealing with builder-grade finishes — stock cabinets, laminate countertops, basic carpet, and standard fixtures — rather than the structural or system issues common in older Boise homes. Meridian remodeling projects tend to focus on upgrading finishes to match the homeowner's taste and needs: replacing builder kitchens with custom layouts, converting tub/shower combos to walk-in showers, opening up floor plans, and adding outdoor living spaces. The city's permit process is straightforward and well-documented through the Meridian Building Department.
Meridian's housing stock is predominantly post-1990 construction. The majority of homes feature PEX plumbing, 200-amp electrical panels, and energy-efficient windows — but with builder-grade interior finishes that homeowners upgrade as the homes age.
1990s (North Meridian)
Early subdivision homes with standard 90s finishes: oak cabinets, laminate countertops, carpet throughout, and basic tile in bathrooms. These homes are 25-35 years old and are the most common full-remodel candidates.
2000s–2010s (South Meridian, Paramount)
Larger homes with better floor plans but still builder-grade finishes. Many have slab granite installed during the granite boom but are now dated. Cabinets, fixtures, and flooring are the primary upgrade targets.
2015–present (South Meridian expansion)
Newer construction with open floor plans and modern systems. Homeowners typically upgrade finishes 3-7 years after purchase — replacing builder-grade countertops, cabinet hardware, lighting, and flooring.
Meridian shares Boise's semi-arid climate with hot summers, cold winters, and low humidity. The same material and construction considerations apply — UV resistance for exterior materials, freeze-thaw durability, and proper insulation.
Hot Summers (90-105°F)
Exterior materials and finishes must resist UV degradation. West-facing windows and walls get the most sun exposure. Proper insulation and HVAC sizing are critical for comfort.
Cold Winters (15-30°F)
Frost depth requirements affect foundation work for additions and ADUs. Plumbing in exterior walls and crawl spaces needs freeze protection.
Wind and Dust
Meridian's open terrain means more wind and dust exposure than central Boise. Exterior finish quality and window sealing matter for long-term durability.
Low Precipitation
Less rain means less exterior moisture exposure, which is favorable for siding and paint longevity. However, irrigation and ground moisture around foundations still require attention.
Permit authority: City of Meridian Building Department
- ✓Permits required for plumbing, electrical, structural, and mechanical work
- ✓HOA approval may be required before city permits for exterior changes
- ✓Online permit portal available for application and tracking
- ✓Standard residential permit processing is typically 1-2 weeks
- ✓ADU construction follows specific zoning criteria with additional review
- ✓Impact fees apply to additions and ADUs that increase square footage
Do ADUs require permits and planning approval?
Yes. ADU projects require building permits, plan review, and multiple inspections. In most Boise-area jurisdictions, ADUs also require zoning compliance review to confirm lot size, setbacks, and parking requirements are met. We handle the entire permitting process.
How much does it cost to build an ADU in the Boise area?
A detached new-construction ADU typically costs $120,000-200,000+ in the Boise area, depending on size, finish level, and site conditions. A garage conversion is typically $80,000-150,000. Costs include design, engineering, permitting, construction, and utility connections.
How long does it take to build an ADU?
From start of design to move-in, a typical ADU project takes 6 to 12 months. This includes design (4-8 weeks), permitting (4-8 weeks), and construction (3-5 months). Garage conversions are faster; detached new construction takes longer.
Can I rent out my ADU?
In most Boise-area jurisdictions, yes. ADUs can be rented as long-term rentals. Short-term rental rules (Airbnb, VRBO) vary by city and may have additional restrictions. Check local regulations before planning a short-term rental strategy.
How much rental income can an ADU generate in Boise?
A well-built one-bedroom ADU in the Boise area can generate $800-1,500+ per month in rental income, depending on location, size, finish level, and market conditions. This income can offset or exceed the monthly cost of financing the ADU construction.
What is the maximum size for an ADU?
Maximum ADU size varies by jurisdiction. In Boise, detached ADUs can be up to 1,000 square feet or 10% of the lot area, whichever is less. Other cities in the Treasure Valley have different size limits. We confirm the specific rules for your property during the feasibility phase.
Do I need to live on the property to have an ADU?
Owner-occupancy requirements vary by jurisdiction. Some cities require the property owner to live in either the primary home or the ADU. Others have relaxed or eliminated owner-occupancy requirements. We confirm the rules for your specific location.
Will an ADU increase my property value?
Yes. A permitted, well-constructed ADU typically adds $100,000-200,000+ to property value in the Boise area — often more than the construction cost. ADUs also make a property more attractive to buyers who value rental income potential or multigenerational living flexibility.
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