Compact Loft ADU
Project Overview
The homeowner needed a compact backyard ADU that could be built efficiently while keeping costs and site impact low. Prenvalley Builders constructed this detached ADU using a helical pier foundation and a highly efficient layout, navigating the challenges of a tight urban lot and small footprint. What makes this project special is how much functionality was achieved within a minimal footprint without sacrificing comfort or long-term performance.
Project Details
Size: 280 sq ft
Location: Denver, Colorado
Architectural Design: NAGY Design Co.
Our Approach
Prenvalley Builders focused on efficient construction methods and careful sequencing to deliver a high-performing ADU within a compact footprint. By utilizing a helical pier foundation and precise framing, the team minimized site disruption while maintaining structural integrity. Close coordination throughout the build ensured a smooth process from foundation to final finishes.
Project Highlights
Constructed a detached ADU with a highly efficient, small-footprint layout
Installed a helical pier foundation to reduce site impact and control costs
Executed precise framing to maximize usable interior space
Built a lofted sleeping area to increase functionality without expanding the footprint
Delivered durable exterior materials suited for Denver’s climate
Completed a full ADU build on a tight urban lot with minimal disruption
Results
The finished ADU delivers a comfortable, fully functional living space within a compact footprint. Thoughtful construction methods and efficient planning resulted in a durable, low-impact backyard residence well suited for Denver’s urban environment. The homeowner gained a versatile ADU that balances performance, cost efficiency, and long-term usability.
Project Goals
Create a compact, fully functional backyard ADU
Minimize construction costs and site disruption
Maximize usable living space within a small footprint
Deliver a durable, low-maintenance structure
Support long-term flexibility for rental or guest use
Common Questions about Accessory Dwelling Units
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This varies quite a bit throughout Colorado based on your city’s specific zoning guidelines. Our team are experts with zoning rules throughout the state and can provide you with a detailed breakdown of what’s possible.
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We usually get asked how much an ADU costs per square foot but this is the hardest metric for an ADU since the cost per square foot parameter can vary drastically based on the size. This is due to the fact that ADUs are small compared to normal homes and the cost per sq. ft. can vary dramatically due to the economy of scale factor. Also, most of the ADUs we build have unfinished garages which complicates that metric even further. We’ve found that ADUs in Denver can vary on average from $250k to $450k based on size, finish level, and site constraints.
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As of right now the average ROI ranges from 4 to 7 years until you begin seeing a net positive on your ADU investment which is based short term renting the space over that time. The problem with ADUs in Colorado is that there aren’t many comparables when appraisers are valuing these spaces so they are typically appraised at a lower value than they were built for. As more ADUs are built and sold with their primary homes, these numbers will improve so this ROI is very much temporary. As of now, ADUs are considered a long term investment and are definitely worth the consideration if you’re looking to hold onto your home for the long run.
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In our experience thus far, the scale of an ADU hasn’t been proven to be built better or more cost effective in a modular format. The modular ADU on paper seems like a great idea but all of the companies we’ve seen provide them are at a comparable price point if not higher and quality issues can occur due to manufacturing, delivery, and assembly issues. We view ADUs as custom small homes that need to be built with care and craftsmanship which can easily be lost in a mass manufacturing process.
