What is an ADU ( Accessory Dwelling Unit )?

ADU’s also known as Accessory Dwelling Units are additional living quarters for a single-family lot. They can be a freestanding unit part or attached to the primary residence. While general contractors were originally building them 20th century they lost popularity for some time.

Currently, ADUs are more popular than ever and they are adding functional and financial value to homes all over Colorado. CWC Construction has built many custom ADUs along the Front Range and we put this together to explain what you need to know about before starting a project like this.

Maximum Habitable Space & Floor Area

Here is clarification on how the limitation on how maximum floor area is different from limits on habitable Space, as the latter term is used to regulate the Detached Accessory Dwelling Unit in single unit districts.

1. Maximum Floor Area refers to the floor area the building creates including the main floor and basement.

2. Habitable space is figured differently from the maximum floor area. The measurement is similar to the measurement of Maximum Floor Area, but Habitable Space excludes habitable space below ground level (e.g., a finished basement).

We’ll help you eliminate the confusion and help guide you through the entire process. For instance, if you are building an ADU on a property that is less than 6,000 square feet, then the maximum size of the footprint is 650 square feet. If the lot is between 6,000 SF and 7,000 SF then you are permitted an 864 square foot building footprint.

What is the cost of constructing an ADU?

The budget will depend on the city you’re wanting to build, but the average cost for a project like this is usually between $300k to $380k. Again every project is different and no home is alike. Depending on existing structural requirements, existing conditions, and finish selections cost for building an ADU can range widely.

Just like constructing a custom home, these projects are a similar experience. Full-service construction including foundation, design, utilities, surveys, and more is required. so of course we recommend hiring an experienced general contractor like CWC construction.

The Benefits of Building an ADU

  • They are typically sustainable buildings carrying a low impact when compared to typical single-family homes. Their smaller size means lower heating and cooling costs and a smaller environmental footprint.
  • Due to the booming popularity of these units, they will add value and potential rental income immediately.
  • Housing for multi-generational and extended family. This allows family/community members a place to live offsetting the expense of senior living facilities and/or child care costs.
  • ADUs provide housing security for both homeowner and renter.
  • Two-story units can have a garage on the lower level and housing/home office above the garage, this creates much-needed additional parking.

ADU Construction Project Sustainable Design-Build

CWC is a sustainable design-build contractor with decades of experience. Ensuring you are working with a general contractor that is experienced in environmentally friendly, sustainable ADU construction is key to maintaining proper heating and cooling.

As you can see there are specific zoning restrictions for ADU construction. It's easy to find out if your property is zoned to allow an ADU. Go to, email-  , or 720-865-3000.

CWC Construction and Remodel has experience with the process and can help you with architectural design and engineering to make your ADU a reality.

Accessory Dwelling Unit

Accessory Dwelling Units