Can you build an ADU on a narrow lot in Denver?

Yes. This project demonstrates how a well-planned construction approach can successfully deliver a full garage ADU on a tight urban lot, even with limited access and surrounding constraints.

What types of ADUs can be built above a garage?

Garage ADUs can include studio layouts, one-bedroom apartments, or a combination of spaces depending on zoning and structure. This project includes both a studio and a one-bedroom unit above a two-car garage.

How do you handle construction challenges like power lines and limited access?

Careful sequencing, material staging, and coordination with utility providers are critical. Prenvalley Builders specializes in managing complex site logistics to keep projects moving safely and efficiently.

Can a rooftop deck be added to a Denver ADU?

Yes, when properly engineered and permitted. This ADU includes a rooftop deck designed to support heavy-use features, expanding usable outdoor living space.

Do ADUs in Denver add long-term value to a property?

A well-built ADU can increase property value, provide rental income potential, and add flexible living space, making it a strong long-term investment for Denver homeowners.

Narrow Lot ADU with Roof Top

ADUNew Construction

Jan 31

Written By Phillip Daughton

Front exterior of a modern garage accessory dwelling unit in Denver featuring vertical siding, a sloped roof, and a two-car garage built by Prenvalley Builders.

Project Overview

Our first accessory dwelling unit in Denver may just be our favorite ADU project. The homeowners wanted a high-functioning accessory dwelling unit that could add flexible living space and long-term value on a tight urban lot. Prenvalley Builders constructed a two-car garage ADU with a studio, one-bedroom apartment, rooftop deck, and solar array, navigating limited site access and overhead power lines throughout the build. What makes this project special is how much livability and performance were achieved within a challenging footprint while maintaining a clean, modern presence.

Project Details

Size: 2,200 sq ft

Location: Sloan Lake, Denver, Colorado

Architectural Design: Prenvalley Builders

Interior Design: NAGY Design Co.

Exterior architectural rendering of a modern garage accessory dwelling unit in Denver with a sloped roof, horizontal siding, and second-story living space built by Prenvalley Builders.

Our Approach

Prenvalley Builders approached this ADU with a strong focus on logistics, sequencing, and build quality, knowing the tight site and surrounding utilities would require careful coordination. By managing access, material staging, and structural execution with precision, the team delivered a high-performing garage ADU without compromising efficiency or craftsmanship.

Project Highlights

Two-car garage ADU with studio and one-bedroom apartment
Built on a narrow lot with complex site logistics
Rooftop deck engineered for heavy-use features
South-facing solar array for improved energy performance
Efficient interior layouts maximizing usable space
Durable exterior materials suited for Denver’s climate

Accessory dwelling unit under construction in Denver showing a garage ADU framed and sheathed on a narrow urban lot with overhead power lines, built by Prenvalley Builders.

Finished exterior of a garage accessory dwelling unit in Denver featuring a two-car garage, sloped roof, vertical siding, and second-story living space built by Prenvalley Builders.

Completed garage accessory dwelling unit in Denver featuring a modern black exterior, sloped roof, vertical siding, and second-story living space built by Prenvalley Builders.

Exterior view of a Denver accessory dwelling unit with a steel staircase leading to a rooftop deck, showcasing efficient urban ADU construction by Prenvalley Builders.

Results

The completed ADU delivers flexible, high-quality living space while adding long-term value to the property. Despite the tight site and logistical challenges, Prenvalley Builders executed a clean, efficient build that performs well and fits seamlessly into its urban Denver setting.

Project Goals

Add flexible living space within a compact urban footprint
Maximize functionality on a narrow Denver lot
Support long-term rental or multi-use living options
Improve overall property value through a high-quality ADU build
Deliver durable, efficient construction suited to Denver’s climate

Interior kitchen of a Denver accessory dwelling unit featuring a quartz island, modern cabinetry, stainless steel appliances, and efficient layout built by Prenvalley Builders.

Open-concept living room and kitchen inside a Denver accessory dwelling unit featuring modern finishes, efficient layout, and natural light built by Prenvalley Builders.

Bedroom inside a Denver accessory dwelling unit featuring recessed lighting, large windows, hardwood flooring, and a comfortable one-bedroom layout built by Prenvalley Builders.

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Phillip Daughton