Denver has some of the most favorable ADU zoning in the country right now. The 2019 Group Living Code opened up by-right ADU permits on most single-family lots across the city — detached backyard cottages, garage conversions, basement apartments. If you've been sitting on a Denver property with a large backyard or an underused garage, the window is open.
Peak Builders has built ADUs across Denver metro for years. Here's what you need to know before starting.
What Makes a Denver ADU Different
Zoning Works in Your Favor
Most Denver single-family zones (E-SU, U-SU, S-SU) allow at least one ADU by-right — no variance, no neighborhood review board, just a permit application. Some zones allow two: a detached cottage plus a basement unit. We verify your specific zone at the first consultation so you know what's actually possible before spending anything.
No Parking Replacement Required
Denver eliminated the off-street parking replacement requirement for most ADU zones. You don't have to add a new parking pad if you're converting a garage. That's one major cost and headache removed from most projects.
Altitude and Construction
At 5,280 feet, Denver code requires R-21 wall insulation and R-49 attic insulation — tighter than most jurisdictions. Gas appliances need high-altitude adjustment. HVAC sizing is different. These aren't optional details: they affect your comfort and your permit approval.
Winter Build Windows
Denver ADU construction can proceed year-round except foundation pours during hard freezes (typically December through February). Interior work, framing, and mechanicals continue through winter. A project started in September typically reaches certificate of occupancy the following summer.
Your ADU Options
Detached backyard cottage — a new stand-alone structure with its own foundation, utilities, kitchen, and bath. Maximum privacy and rental value. Most commonly built 400–800 sq ft.
Garage conversion — turning an existing detached or attached garage into living space. Faster permit process, lower cost. The existing structure means less framing and no new foundation.
Basement ADU — a legal separate-entry apartment carved out of an existing unfinished basement. Most cost-effective ADU path if you have the right basement layout. Requires a separate exterior entrance and egress windows in any sleeping rooms.
What We Handle
We manage design, soil testing, engineering, permits, foundation, framing, MEP rough-in and finish, insulation, drywall, cabinetry, flooring, and final inspections. You get one contract, one project manager, and one warranty.
Historic Neighborhoods
If your property is in Wash Park, Country Club, Capitol Hill, or another historic overlay district, a detached ADU typically requires Denver Landmark Preservation Commission review. That adds time — usually 8–12 weeks — and may require exterior design modifications. We flag this at the first consultation before you've committed to anything.
Getting Started
The first step is a free on-site feasibility consultation. We look at your property, verify your zone, and tell you what's actually buildable before you make any decisions.
Call (720) 605-7785 or book online.
