Making New Spaces

Build a Small Casita for Guests or Family. And Maybe Income?

Across southern Arizona, homeowners are building casitas — technically known as accessory dwelling units or ADUs — for adult children and elderly parents who want to age gracefully close to family and as short-term rentals and studios.

What size casitas are most commonly built in Arizona? 

Casitas are overwhelmingly used to house a member of the family or the extended family. The most popular size we see are studios and one-bedrooms, from 400-800 square feet.

What would be the largest casita possible under city regulations? And the smallest?

The City has a few ways to calculate size limits based on lot coverage or lot size, so the "largest" answer varies a lot. Generally, most are 1000 square feet or less. You could use a casita this size for an income property.  

I have seen a really cute casita that is only 144 square feet and is permitted in the city of Tucson! That would be a perfect size for someone who is looking for a home office, or an extra guest room. 

What other processes, requirements, or restrictions are in effect in the city of Tucson?

The City is developing a model plan library for casitas! It gives homeowners a chance to purchase plans that are pre-approved. With a site plan that places the design on their specific property, there is a quick zoning review, and building permits can be available within a matter of weeks. Several of these plans are already available. 

As far as requirements, a casita must have a cool roof and one parking space must be provided. The parking space can be on the street and even waived if you are within a quarter mile of a bike boulevard or a bus stop. 

What about building in Pima County?

Pima County recently updated its code! The minimum lot size is now 4,000 square feet, and the casita size is limited to only 70% lot coverage. This means they are getting more flexible with the size of the dwelling units as long as there is a minimum of 30% total open space on your lot. 

There are other limitations in Pima County: you are not allowed to have separate utility meters, and casitas cannot be rented out. They are intended for multigenerational family living, workshops or other accessory uses, or non-paying guests. 

How does building ADUs in southern Arizona compare with, say, Los Angeles?

I was living in Los Angeles when the ADU ordinance passed there in 2016, and that's what ignited my passion for this housing type. I built my first ADU out of a shipping container in Palm Springs in 2016. I have been advocating for them ever since. I believe it is an accessible form of affordable, in-fill housing that really can make an impact on the housing crisis. California had over 30,000 ADU permits in 2022. 

Tucson is uniquely positioned; casitas are already part of our cultural lexicon and featured on many existing properties. Leaning into the casita as a multigenerational or affordable housing option embraces and celebrates what has historically existed here.

Are there unique furnishings or appliances used to get the most out of the smaller footprint of a casita?

There are so many clever options for living smaller these days! From efficient kitchenette all-in-one units to multi-use storage loft spaces, there are countless ways to enjoy living in a casita under 600 square feet. 

And don't forget more roof space for rainwater harvesting or solar when thinking about getting the most out of your casita!

What construction material do you recommend?

We recommend the materials that will work best for our client's needs. For those most concerned with budget, wood frame and stucco are standard. It is the most efficient and fastest assembly method. Other clients place more importance on their desire for materials like brick or even straw bale wall panels. Coming from larger-scale construction backgrounds, Jon and I can build with any material or method, but we always recommend what is best for the project. 

What is the typical pricing to build a casita?

The Barrio Viejo casita is 400 square feet and is coming in at $150,000. We are on schedule to finish it in just 3 months.

Share a few examples of ADUs you've built to illustrate the range of options available to homeowners.

We've done a carport conversion in Rosemont West for a grandson to live in, an attached masonry structure for a growing family in Sam Hughes, and a detached casita in Barrio Viejo for a paramour. We have another carport conversion and another detached casita in the pipeline. 

Our specialty — and the most traditional — is detached casitas. They are the most cost-efficient and least complicated to build. 

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