Guide
About 3 min read
What does an ADU actually cost? We use Colorado for concrete ranges and code texture, but the same budgeting mindset applies anywhere in the U.S. - workshop conversions, backyard studios, and compact rental units all hinge on size, site work, utilities, and structure type.
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Most detached ADUs fall into a wide band depending on scope - here we ground numbers in Colorado, where small garage conversions may land lower and new two-story backyard units with quality finishes can land much higher. Regional labor, climate, and structural loads differ everywhere: use these bands as a conversation starter, then calibrate with local proposals.
Use these figures as planning conversations - not quotes. A licensed architect or builder in your county can translate your site constraints into a real number.
Municipalities differ on ADU allowances, parking, and utility fees. Before you lock a budget, confirm what your local zoning allows and what tap or extension fees will apply.
Browse curated ADU-friendly plans and modern small-footprint designs on our marketplace, compare professionals, and post an open project when you want structured proposals.
Short answers grounded in how real projects move—then use PlanGrounds to compare professionals and proposals when you're ready.
Often smaller overall, but not always cheaper per square foot. ADUs still need full kitchens and baths, utilities, foundations or structural work, and code-compliant envelopes - tight backyards can drive site costs up. Use ranges as planning numbers; get local proposals before you lock a budget.
It depends on scope, jurisdiction, and whether you’re adapting a stock plan. Many Colorado projects benefit from professional design for energy code, snow loads, drainage, and daylighting - even when you start from an off-the-shelf plan. Your city or county can tell you what level of documentation permits require.
Tap fees, utility extensions, surveys, soils, design and engineering, permitting, and contingency for unknowns (especially in older neighborhoods). If you’re comparing a garage conversion to a new detached unit, foundation and roof work can swing the total more than the floor plan suggests.
Yes. Browse plans with filters for size and style, save favorites, compare professionals by region and specialty, and start a project when you want structured proposals instead of one-off cold emails.
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ADU regulations in Colorado (what to verify locally)
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Understand the tradeoffs between hiring an architect-led team and a design-build firm - before you choose a contract structure.
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This guide is for general education only. It is not legal, engineering, or financial advice. Budgets and codes vary by site and jurisdiction—hire qualified professionals for decisions that affect safety, compliance, or investment.