Golden CO ADU Permits: How to Navigate the Process

Accessory Dwelling Units (ADUs) are small living units that are added, either attached or detached, to an existing single-family home or duplex. In 2024, Colorado passed House Bill HB24-1152, which requires cities of a certain size, like Golden, to allow for more ADUs to be built, and also reduces the zoning ADU requirements that had previously created barriers to their construction, such as required set-backs of buildings from property lines or public hearings for permitting plans. Also known as carriage houses or mother-in-law flats, ADUs present an important opportunity for building additional housing in areas with housing shortages, or they can allow for older generations to age in place while staying close to family. If you’re interested in how to build an ADU in Golden, Colorado, read on for everything you need to know.

Understanding Permit Types in Golden

Building an Accessory Dwelling Unit requires understanding which of Golden’s new home construction permits may be required: 

1. Building Contractor License/Registration
   1. The City of Golden requires all licensed contractors to be listed on a building permit before the permit can be issued or inspections occur.
   2. Certificates of liability are not required, but state license information is required for plumbers and electricians.
      
2. Golden CO Building Permits
   1. A building permit is required for most major construction in Golden, including enlarging,
      
3. Right of Way Permit
   1. If construction will require a dumpster to be parked on the road, a Right of Way Permit will be required.
      

ADU-Specific Zoning & Regulations

When you start thinking about building an ADU, you must consider the Golden CO zoning ADU requirements, as defined by the Municipal Code. Within Golden, an ADU is defined as a fully separate living space that includes a kitchen (with a stove top and oven), a full bathroom, and a bedroom, and a notarized Accessory Dwelling Unit Deed Restriction must be filed with the county clerk and recorder.

• An ADU must be built within one of the residential zones: RE, R1, R1A, R2, R3, or PUD; it must be built on a lot developed to be a one household dwelling unit or two household dwelling units; only one ADU can be built per lot; and the ADU must have one on-site parking spot.
  
• The size of an ADU is dependent on the size of the primary dwelling. For primary structures larger than 1,000 square feet, the ADU can be no larger than 800 square feet or 50% of the size of the primary dwelling (whichever is smaller; and for primary structures smaller than 1,000 square feet, the ADU can be no larger than 500 square feet. In all cases, no ADU may be less than 200 square feet.
  
• The property owner must live in the primary dwelling; no more than three people may occupy an ADU; utilities must be connected to the same lines as the main dwelling; and there must be outdoor space and landscaping for both the primary and accessory dwellings.
  
• The exterior design of the ADU must correspond to the primary dwelling in terms of exterior materials; the front door must be obviously subordinate to the entryway of the primary dwelling, and windows must be placed so as to protect the privacy of neighbors.

Step–by–Step Permit Process

Although the Golden ADU permit process can be time-consuming, the City of Golden has ample resources to simplify the process. Follow these steps for Golden, CO building permits:

1. To simplify the entire process, contact Little Home Builder for a free consultation or feasibility review.
   
2. After that, verify the building address is located within Golden city limits using the Jefferson County Address Wizard. Enter the address, select the address, then locate “Municipal Status” at the bottom of the page.
   
3. If the Address Wizard indicates the address is in unincorporated Jefferson County, rather than Golden city limits, Jefferson County Building Safety Division will be the correct point of contact.
   
4. If the City of Golden is the correct municipality, register for an online account on the Online Permit Portal.
   
5. Within the permitting portal, apply for the appropriate permits
   
6. If not already on file, apply for a Contractor License or renew an existing one.
   
7. After the Contractor License has been obtained, apply for a Building Permit under “Building.”
   1. For ADUs, a plan review will be required.
      
8. Once construction is complete, an inspection must be scheduled, where a city inspector verifies that the construction complies with building codes, design criteria, city ordinances, and the approved, permitted plans.
   1. Request the inspection through the Online Permit portal.
   2. Navigate to the correct permit record, select the “Record Info” drop-down option, then “Inspections.”
      
9. Celebrate the new ADU!

Code Requirements & Engineering Standards

The City of Golden upholds the following codes:

• 2024 International Building Code 
• 2021 International Energy Conservation Code 
• 2021International Fire Code
• 2021 International Fuel Gas Code
• 2021 International Existing Buildings Code
• 2021International Mechanical Code
• 2021 International Plumbing Code
• 2021 International Residential Code
  (Including Appendix Chapter F dealing with radon control for new single family dwellings)
• 2020 National Electrical Code

All structures must also meet to meet the following structural design criteria:

• Ground Snow Load:  42.9 p.s.f.
• Wind Load:  V ult 150 m.p.h. ~ exposure C
• Roof Snow Load:  30 p.s.f.
• Frost Depth:  36 inches

Fees, Taxes & Timelines

The City of Golden, Colorado, charges the following fees to build an ADU:

• Contractor License Fees
  • Contractor License Fee: $100
  • Electrical Contractors: No fee
    
• Building Permit fees are calculated based on the total valuation of the build
  • In this case, valuation means the cost of labor + materials
  • City Council Resolutions have determined the fees, which can be found in this table.
    
• Golden charges a 3% use tax on building materials (1.5% total valuation).
  • An additional plan review fee of 65% of the permit fee may also be assessed.

Common Pitfalls & Expert Tips

With a major construction project like an accessory dwelling unit, planning is essential. The most important consideration in a project like this is choosing the correct contractor. The right contractor will help ensure the design-build process is seamless, starting from obtaining the correct permits, and creating a plan within code and within budget. Without an experienced contractor, the process may be riddled with these common pitfalls.

Breaching ADU Regulations

Although we have tried to provide an overview of ADU coding, building codes are complicated. Misunderstanding these regulations can cost extra time and money. For example, the city of Golden charges $50 per hour for additional plan reviews caused by changes or revisions.

Not Allowing Enough Natural Light

Since the design restrictions for building an ADU in Golden include the requirement that windows must be placed to allow for the privacy of neighbors, it can be tempting to limit the number of windows to simplify the design. However, with the small square footage, natural light is essential for avoiding feelings of claustrophobia. If exterior windows don’t allow for privacy, and the lot lines don’t provide the opportunity to build privacy fencing, sky lights are a plausible alternative.

Not Planning for Interior Design 

In a small space, vertical storage will be essential, which means making use of every inch of wall space. In order to do so, adequate blocking must be installed during the framing process to provide support for hanging fixtures like shelves, cabinets, and other mounted hardware. The best contractors consider both the interior and exterior in the design-build process.

Minimal Sound-Proofing

In small spaces, sounds will be amplified. To protect spaces like the living room and bedroom from noises from the kitchen or bathroom, consider a soundproof or well-insulated wall to protect the bedroom at a minimum.

Estimated Timeline Overview

The overall timeline for building an Accessory Dwelling Unit in Golden, Colorado, can range between 6 to 18 months, depending on the design complexity, timeline of the permitting process, the availability of construction materials, and the availability of contractors. In general, the design phase can take two to four months, the permitting can take three to nine months, and construction can take five to seven months. 

Design Phase

• Schedule consultations with multiple contractors to review the vision, design, and budget for the ADU.
• Finalize the choice of contractor, then complete a site visit to determine topography, utilities, soil conditions, all of which impact the design.
• Create detailed drawings, architectural plans, and structural calculations, taking into account zoning regulations.
  

Permitting Process

• After applying for the proper permits, the city will review plans and either request revisions or approve the original plans. The timeline for this process depends on the city’s current resources.
  

Construction

• Site preparation: Remove existing structures and debris from the construction site; take precautions to protect landscaping and nearby structures; then lay the foundation for the ADU.
• Build the structure: The specific type of ADU (attached vs detached, for example) will determine the length of time and complexity of the building process. Modular or pre-fab construction can be built off site, but stick build construction, like that used by Little Home Builder, is site-specific and takes longer, but is generally higher quality with craftsmanship guarantees.
• Connect utilities: This step is particularly important because of the zoning edict in Golden that requires the ADU utilities to be connected to the same lines as the main dwelling. At the same time, the interior work is completed, including flooring, insulation, drywall, cabinetry, plumbing, and all permanent fixtures.
  

Inspection and final walk-through

• After construction is complete, the city of Golden must complete an inspection to determine whether or not the building was constructed according to code and safety standards. It is also important that the building matches the plans as originally submitted to the city. If the city requires any changes to be made, they must be completed before final sign-off for occupancy.

The process of building an Accessory Dwelling Unit in Golden, CO can be complicated, and the right team can help simplify the entire process. Whether you’re a homeowner hoping to earn some additional income or a grandparent hoping to age in place near your family, contact Little Home Builder for a free consultation or a more complete feasibility review.