Salt Lake City Accessory Dwelling Unit – ADU – Builder.

Every square foot of your property has potential. It’s up to you to make the most of it. A growing number of homeowners in Salt Lake City are investing in an Accessory Dwelling Unit – ADU​, to increase the value of their properties while enhancing overall livability in a variety of ways. The skilled accessory dwelling unit builder Salt Lake City team at Johnston Construction LLC works closely with each client to ensure their unique vision for the perfect ADU is achieved.

UPDATE: The laws for all municipalities have changed, read how it affects you.

What Is an Accessory Dwelling Unit?

An accessory dwelling unit is an additional living space built on the property of a single-family home. Also known as granny flats or backyard cottages, they increase the versatility of your property by allowing additional living space that can be used for:

  • Guests
  • Renters
  • Assisted living for elderly parents
  • Home office
  • Your own personal space

Depending on the purpose you envision your Salt Lake City accessory dwelling unit to serve, there are very specific details that must be explored. Our team knows the right questions to ask to ensure you get exactly what you’re looking for and more.

Getting The Job Done Right

Thinking of planning and constructing an accessory dwelling unit? Johnston Construction is your choice for an Accessory Dwelling Unit – ADU in Salt Lake City and the surrounding areas. Keep in mind, unless you’re well-versed in Salt Lake City building codes and have access to the tools and experience to get the job done right, unexpected setbacks are inevitable.

Our team also builds accessory dwelling units in Park City, Utah and is here to take the stress out of accessory dwelling unit logistics. We carefully plan around your exact specifications and guarantee the level of skill and expertise to make your vision a tangible reality.

ADU Costs: $190-$240 per square foot, 90-day build*

Tell us about your project:

I'm interested in a:

ADU Attached to House above Garage

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ADU’s we offer:

In-home Conversion

ADU in home conversion

Attached to home

ADU - Attached to home

Detached Unit

ADU - Detached Unit

Attached to Garage

ADU - Attached to Garage

Attached Above Garage

ADU - Attached Above Garage
Backyard Garage Conversion
ADU - Attached Above Garage


Can I build an ADU on my property?

It depends on the zoning in your city, for example in Salt Lake, Millcreek, ADUs are legal, in Holladay and Herriman, they are not legal, in Cottonwood Heights there are not legal or illegal. We will check with your city to determine if you can build an ADU. Included in our cost is securing all of the correct permits required for building an ADU. UPDATE: The state of Utah passed and ADU law, basically overriding local ordinances against ADUs, but check with your municipality for the latest laws.

How Much Does an ADU cost?

An ADU can cost from the low $100,000’s and up depending on design. A lot of factors can alter the final costs, Johnston Contruction | ADUs have a set price of $190-$240 per square foot.

How Big Can My ADU Be?

50% of your home’s footprint or a maximum of 650 sq ft. which ever is smaller.

How many ADUs can I put on my property.


*Typically $190-240 per sq. ft. depending on type of building. We build to suit, your design, our design. 90 days after permits are ready.