ADU FAQs2024-01-26T10:51:35-05:00


What to know when building an ADU.

Do you have a model home? Can I see an ADU in person?2024-01-25T09:12:29-05:00

The ADUs that are constructed serve as private residences, and as such, we don’t offer model homes for tours. Our primary focus is on designing for clients and producing detailed construction drawings that General Contractors use for execution and construction.

While we don’t provide physical tours, we can offer a condensed sample from our Construction Document set. This glimpse showcases the detail and depth present in our design and construction drawings. We hope this provides you with valuable insights to make an informed decision about your ADU project.

How do I know your ADU designs will give me a quality build?2024-01-25T09:12:07-05:00

Ensuring a quality-built ADU extends beyond the drawings alone, however, the drawings are one of the most critical pieces. Overall, achieving good construction hinges on various factors. A reputable and experienced General Contractor, reliable subcontractors, and quality suppliers play pivotal roles as well. It’s imperative to prioritize quality materials and steer clear of sources like Amazon. Architectural drawings should also be adhered to.

Other factors such as: home maintenance, proper storage of materials during construction, prompt home repairs when needed. Effective moisture protection is a must –the drawings incorporate sound strategies for this purpose. Proper site grading away from the home, and meticulous attention to quality foundation construction are also key elements in ensuring the successful realization of a well-built ADU. So, while the construction drawings are imperative for any construction project, having a durable home for generations depends on many other things working together.

How do I find a General Contractor? Do you have any contractor recommendations?2024-01-25T09:19:35-05:00

To find a general contractor, we recommend the following steps:

  1. Look for a small home builder experienced in sustainable construction. Avoid those unfamiliar with these methods to prevent potential cost increases.
  2. Interview multiple contractors to assess communication, work style, and pricing. Costs can vary significantly.
  3. Ask important questions:
    • Can you provide references?
    • Are you licensed?
    • Will you secure all required building permits?
    • What types of insurance do you carry?
    • What is the expected project timeline? (Our projects typically take at least a month less than typical constructions.)
    • Do you provide a warranty on your build?
    • What drawings do you need for a cost estimate?
  4. Initially, seek recommendations from friends or family. If unavailable, check local sources like your local Chamber, HomeAdviser, Angie’s List, and Houzz.
  5. After identifying a few contractors you prefer, we can provide you with a selection of key drawings from the construction document set to facilitate pricing. Following the contractor selection, we remain accessible for a brief call to address any construction-related details.
How much does it cost to build an ADU?2024-01-25T09:53:52-05:00

While we have put forth every effort to design an affordable small home, the final pricing is determined by your General Contractor based on various factors such as material price, construction labor, site conditions, utility connections, inflation, and GC factors like their current project load, GC profit and overhead, and market volatility.

As of January 2024, the estimated cost to build an ADU in Raleigh, North Carolina ranges from $240 to $350 per square foot. In other jurisdictions, construction costs can escalate to $500 per square foot. Considering the construction escalation due to market volatility, we strongly advise bringing on a general contractor early for current construction estimates.

Each contractor and subcontractor may price a project differently. We recommend obtaining estimates from at least three different contractors for comparison. Keep in mind that ADUs typically cost more per square foot than regular-sized homes due to economies of scale. With smaller square footage, the same amount of labor needs to be distributed over a smaller area, making small homes comparatively more expensive on a per-square-foot basis (but not overall).

Recently, we’ve observed a variability of 25-40% among contractors in some cases. Stressing the importance of speaking with multiple contractors cannot be overstated.

What is the best way to reduce costs when building my ADU?2024-01-25T09:26:30-05:00

The most effective cost-cutting strategy for a small home involves designing efficient structures (foundation, exterior walls, roof), reducing construction time, choosing reputable material manufacturers that warranty their materials.

Given the home’s size, opting for cheap finishes will not significantly impact the overall price, but can actually impair the long-term value.

Where you should expect to see savings in our ADUs over the average ADU build:


  • Soft Fees: Traditional design fees, typically 10% to 25% of total construction costs, are avoided by using pre-designed house plans. This not only saves four to six months of design time but also results in savings of $30,000 to $50,000 in design fees.
  • Manufactured Foundation System for some of our ADU designs: This system requires minimal excavation (moderate site grading for drainage and minimal excavation for utilities only), saving several weeks of construction time.
  • An efficient structural design leads to quicker construction by facilitating easy installation and simplified material sourcing.
  • Long-term Energy Savings: Achieved through a tight building envelope and the use of energy-star appliances.
  • No Large Machinery Needed: Design considerations for potential narrow or limited access to the backyard mean that all materials can be placed and installed by hand or using small machines such as jackhammers.

Longevity & Durability: Our homes are designed for lasting durability, featuring high-quality finishes like fiberglass windows, standing seam roofs, and engineered wood floors. This design approach contrasts with generic builder homes that may require frequent maintenance and premature finish replacements.

What does Fast Track mean?2024-01-25T09:27:38-05:00

Designs featured in the Raleigh ADU Fast Track Gallery have undergone pre-review by the City of Raleigh for Building Code compliance. Choosing a pre-reviewed design can expedite your permit review by up to two weeks. However, it’s important to note that, before proceeding with ADU construction, you must apply for and obtain all necessary permits, including Building Code permits. Additionally, your lot must undergo a zoning review by the City’s Planning Department to assess development regulations specific to your site. A site plan is mandatory for all ADU permit applications.

What are the benefits of the Fast Track program?2024-01-25T09:28:20-05:00

As outlined in “What does Fast Track mean,” you can expedite the permit review process by up to two weeks. However, the substantial advantage lies in bypassing the conventional building design process, potentially saving three to six months and avoiding design fees ranging from $30k to $50k.

Can I build an ADU on my lot? How do I know what size?2024-01-25T09:31:46-05:00

Review the Unified Development Ordinance (UDO) applicable to your zoning code. If you live outside of Raleigh or North Carolina, to find information specific to your city, enter “[your city]”plus “zoning ordinance” as well as “[your city]” plus “zoning map” in your browser search bar to determine your zoning district.

What comes with a purchase? What is the final product?2024-01-25T13:18:34-05:00

When you acquire a license for our ADU designs, you’ll receive digital House Plans, also known as Construction Documents.

Construction Documents encompass the written and graphic materials crafted by an architect to articulate and convey the design, structure, and physical attributes of a building project. These documents are essential for obtaining building permits and serve as the required documentation for managing the construction contract between the owner and the General Contractor. Our ADU House Plans comprise a comprehensive construction document set, ready for your contractor to execute into a physical building! 

Constructing a building is a complex process that requires the coordination of numerous trades and components. While it can be a meticulous service, having the right set of construction documents makes the building process not only rewarding but also somewhat easier. Additionally, unlike most house plans that lack interior design details, we have gone above and beyond to provide thoroughly-detailed, ready-to-build documentation. This requires no further involvement on our part and minimal effort on your end!

Why choose an architect-designed small home or ADU rather than a builder home?2024-01-25T09:34:24-05:00
  1. Design Expertise: Architects are trained to create functional, aesthetically-pleasing, and innovative designs. They excel in understanding human needs and translating them into well-designed homes. In contrast, builders often follow a more standardized approach that may lack personalization.
  2. Innovative Ideas: Architects bring a fresh perspective to your project. They stay updated on the latest trends, materials, and construction techniques, offering innovative ideas that can enhance the functionality and aesthetics of your home.
  3. Problem Solving: Architects are skilled problem solvers. They can address challenges related to the site, local building codes, and your specific requirements. Their expertise can result in creative solutions that make the most of your property and budget.
  4. Cost-Efficiency: While architects may have fees, their involvement can lead to cost savings in the long run. A well-designed home can optimize space, energy efficiency, and materials, potentially reducing construction and operational costs over time.
  5. Legal Compliance: Architects are familiar with local building codes and regulations, ensuring that your project complies with all legal requirements. This can save you time and potential legal issues down the road.
  6. Value Enhancement: A well-designed and architecturally significant home can potentially increase its resale value. Buyers often appreciate the attention to detail and thoughtful design elements that architects bring to a project.
  7. Long-Term Vision: Architects consider the long-term implications of design decisions. They can help future-proof your home by incorporating features that allow for adaptation to changing needs and technologies.

While builders play a crucial role in executing the construction, architects contribute to the vision, planning, and overall success of a project. The collaboration between architects and builders is often essential to create a home that is both well-designed and well-constructed.

What is the process to get an ADU built?2024-01-30T05:07:10-05:00


  • To identify the optimal location for your ADU, assess your lot’s legal boundaries, zoning restrictions, topography, and adjacent features, culminating in a Site Plan drawing necessary for obtaining a building permit.


  • Secure a contractor early to ensure a smooth construction process. Once the contractor is procured, they will oversee the entire building process using the detailed House Plans provided. We are available for any questions or clarifications.


  • The City mandates a review of the ADU project for land use and zoning codes, necessitating the creation of a unique Site Plan for each lot. Your contractor can organize this plan, incorporating a topographical survey detailing legal boundaries, road frontage, topography, utility locations, flood hazard areas, stormwater management, hard surfaces, and existing structures on the property.


  • Each project site’s uniqueness in soils and topography requires confirmation of the ADU’s foundation layout through a site-specific assessment. Engage a soils engineer to test your site’s soils,
  • For the Ascension Home foundation, the foundation manufacturer will organize this process with your GC. Expect a project service fee of around $1,500. While the manufactured foundation installation is swift, obtaining confirmed components can take up to eight weeks, so ordering in advance is advisable.
  • For an ADU with a slab-on-grade foundation, an engineering review is also necessary, managed by your General Contractor with associated fees typically amounting to a few hundred dollars.


  • Once the site plan is ready, your Contractor can initiate the permit process by submitting an application on the City’s Building Permit Portal, along with the site plan, complete ADU drawing set, and necessary documents such as a certificate of workers’ compensation insurance. During the review, the City may request clarifications, and your General Contractor will manage communication



  • Your contractor will schedule essential rough-in inspections with the City throughout the construction process. Once all final inspections are completed, you can apply for a Certificate of Occupancy, which will be issued by the City upon successful completion of all inspections.

See How to Get Your ADU Built for more detailed steps.

I do not live in Raleigh or North Carolina. Could I still buy the design and use the construction documents?2024-01-25T09:37:52-05:00

Certainly! Atmos Arc designs and plans adhere to International Residential Code 2015 standards, which is adopted by most municipalities as a baseline for their codes. While your construction plans may be permit-ready at the time of purchase, it’s advisable to engage a local building professional (engineer, architect, builder) to verify compliance or make necessary modifications based on specific jurisdiction requirements. If you’re outside of North Carolina, your local jurisdiction might require an engineer to review and stamp your drawings for your lot.

I want to build an ADU. What do I need to know?2024-01-30T05:09:08-05:00

Constructing an ADU is a genuine construction project, akin to building any home. However, our designs and detailed plans streamline the process. First, it is imperative to align your ADU with local zoning regulations regarding size and location. Secondly, you need to engage a reputable General Contractor.

The drawings serve as one half of the project, with the other half is the physical implementation of the drawings which is overseen by your General Contractor who acts as the project manager and interfaces with the building department on your behalf.

See How to Get Your ADU Built for more detailed steps.

Are any of the ADUs accessible?2024-01-25T09:41:40-05:00

We promote universal accessibility in all building design. Although our plans are not explicitly ADA-compliant, we offer two designs already on grade, featuring 36” doors in key rooms such as bedrooms and all are designed with minimum 40 inch wide hallways. Moreover, all designs can be adapted to meet accessibility needs, and we can explore specific plans for wheelchair accessibility.

How long does it take to build an ADU?2024-01-30T05:28:00-05:00

Our designs prioritize efficient structures, notably the Ascension Home ADU, where the exterior envelope and foundation can be installed in one week. As designers, we’ve done our best to expedite the construction process, however, the overall time frame for your ADU to be move-in ready ranges from five to nine months due to a number of factors. 

Permitting typically takes one to two months. Material lead times range from several weeks to a couple of months. The actual build phase, approximately three to six months, depends on your contractor, their teams, and their project workload. Finally, scheduling and obtaining final city inspections during construction can take several days to several weeks at each phase.

Recognizing that construction timelines in the United States are often prolonged due to factors like market volatility, an aging construction labor market, and a lagging regulatory environment, we aim to address this issue by designing prefabricated and modular homes this year.

I am a GC. Can I be recommended to your clients and customers?2024-01-25T09:47:32-05:00

Certainly! We frequently receive inquiries from customers seeking contractor recommendations, and we are continually looking for high-quality, reputable builders to partner with or recommend. Please reach out via private email to initiate further discussion.

Can I customize my ADU?2024-01-30T05:29:33-05:00

Certainly. You have the flexibility to choose between two exterior color options: Norwegian Wood (gray vertical siding with wood-colored accent siding) or Shady Gray (white vertical siding and gray accents). We can also work with you for custom exterior colors to match your principal residence. Additionally, you can customize interior finishes colors and light fixtures. Note that this does require adjustments in the drawings which will incur a flat fee of $175 for color changes.

While you can change appliances, it is your responsibility to ensure their compatibility with designated spaces.

Modifications to the plan or design are also allowed for a fee charged by the hour. Note that any changes to the Fast Track pre-reviewed designs will disqualify them from the expedited permit review process.

Contact for more info

Looking to build an ADU? Check out our catalog!

Choose from our affordable 2 bedroom and 1 bedroom designs.

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