Salt Lake City & Surrounding Areas 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 also known as an 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. Call us for a free consultation.

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

What is an Accessory Dwelling Unit?

An accessory dwelling unit is a separated living space built on the property of a single-family home. Sometimes referred to as granny flats or backyard cottages, they increase the value and 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

We will help you arrive at the best ADU solution as well as oversee the entire process from planning, construction and everything up to the day you move-in, we offer accellerated timelines.

Successful ADUs require good planning

Thinking of planning and constructing an accessory dwelling unit? Johnston Construction is your choice for an Accessory Dwelling Unit – ADU in the Salt Lake City Area. We offer total planning and construction services .

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*

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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.