How large can an ADU be in Denver?

Denver allows ADUs up to a defined maximum based on zoning and lot conditions. This project demonstrates how thoughtful design and planning can maximize allowable square footage while staying fully compliant with local regulations.

Can an ADU include a garage and workspace?

Yes. This ADU was designed with an integrated garage, office, and workshop, showing how accessory dwellings can support flexible uses beyond just living space.

Is a two-story ADU a good option for small urban lots?

A two-story ADU is often the best way to maximize livable square footage on compact lots. Building vertically allows for better separation of living, working, and utility spaces.

How do you keep ADU projects cost-effective?

Cost control starts with smart planning. Prenvalley Builders balances layout efficiency, structural decisions, and modest finish selections to manage budgets without sacrificing durability or performance.

Does Prenvalley Builders handle both design and construction?

Yes. Prenvalley Builders uses a design-build approach, managing the project from early planning through construction to ensure alignment, efficiency, and a smoother overall process.

Large-Scale Urban ADU

ADUNew Construction

Dec 10

Written By Phillip Daughton

Project Overview

The homeowners needed a large, flexible ADU with space for a second bedroom, home office, and workshop while keeping finishes modest to manage costs. Prenvalley Builders designed and built a two-story, garage-integrated ADU that maximizes usable square footage on a compact Denver lot. What makes this project special is its scale and versatility, making it one of Prenvalley’s largest ADUs to date while remaining efficient and thoughtfully planned.

Project Details

Size: 600 sq ft (not including garage + workshop)

Location: Denver, Colorado

Architectural Design: Prenvalley Builders

Architectural rendering of a two-story design-build ADU in Denver showing integrated garage, second-floor living space, and compact massing by Prenvalley Builders

First-floor plan of a custom design-build ADU in Denver showing garage, office, workshop, bathroom, and EV-ready space by Prenvalley Builders

Second-floor plan of a custom two-bedroom ADU in Denver showing kitchen, living room, bedrooms, bathroom, and efficient layout by Prenvalley Builders

Our Approach

Prenvalley Builders approached this ADU with a design-build strategy focused on efficiency, flexibility, and long-term use. By carefully coordinating layout, structure, and systems from the start, the team maximized square footage while keeping construction costs in check. The result is a well-balanced ADU that reflects Prenvalley’s experience building high-performing, thoughtfully planned spaces in Denver’s urban neighborhoods.

Project Highlights

One of Prenvalley’s largest ADUs to date
Two-story layout maximizing usable square footage
Integrated garage with EV-ready capability
Flexible office and workshop spaces
Two-bedroom upper-level living plan
Cost-conscious material selections
High-performance building envelope
Roll up garage door making backyard and workshop versatile

Early foundation construction of a custom design-build ADU in Denver showing formwork, excavation, and site preparation by Prenvalley Builders

Two-story design-build ADU in Denver during framing with ZIP System sheathing and installed windows by Prenvalley Builders

Rear elevation of a two-story design-build ADU in Denver with vertical siding, second-floor windows, and a ground-level entry by Prenvalley Builders

Exterior view of a two-story design-build ADU in Denver featuring green vertical and horizontal siding, integrated garage, and compact urban footprint by Prenvalley Builders

Results

The completed ADU delivers a spacious, flexible living environment that supports work, storage, and everyday living within a compact urban footprint. Thoughtful planning and efficient construction allowed the project to balance scale and budget while maintaining long-term performance. The result is a highly functional ADU designed to adapt to changing needs over time.

Project Goals

Maximize usable square footage within zoning constraints
Create flexible spaces for living, working, and storage
Maintain cost control through modest finish selections
Support long-term adaptability and functionality
Deliver a durable, high-performance ADU for urban living

Phillip Daughton