ADU Cost: Complete ADU Development Cost Breakdown

Sep 15, 2021 | ADU

The most common question we get as ADU professionals is: how much does it cost to build an ADU?

After a first consultation, the majority of those who are looking to develop an ADU are amazed at the actual costs. Often, actual ADU costs are not synced with what they have read online or with the information they have received from contractors.

To start with, it’s important to understand that developing an ADU is very much like developing a new house. Therefore, the process and costs associated with it are like those you face when developing a new home, with a few adjustments.

Table of Contents


4 Main ADU Development Costs

Before you even begin planning your ADU, you should be aware that developing an ADU has four main costs involved to it:

  1. Design and planning
  2. City fees
  3. Construction labor and material
  4. Finish materials

It is important to remember that these are just broad categories. Each category is broken down into more single items that add up to result in the total ADU cost of that category.


ADU Design and Planning Costs

There is a lot more that goes into design and planning than many people realize. For starters, you are going to have to work with a team of professionals in order to obtain all the different drawings and calculations that are needed. Just a few ADU costs associated with this category include:

  • Architectural drawings
  • Engineer calculations
  • Energy calculations
  • Land surveys

These costs will vary from person to person depending on your specific ADU requirements and needs. However, the average costs of ADU design and planning are between $6,000.00 to $14,000.00. Where you fall on this scale is completely dependent upon your design tastes and size requirements. Also, your ability to find ADU professionals that are willing to work with you, not just take your money.

Check out our ADU eCourse for a design and planning budgeting sheet to help you get an accurate idea of how much your ADU will cost.


City Fees Associated with ADUs

Every city you build an ADU in will require you to pay certain fees. These fees include things like:

  • Plan check
  • Impact fees – for certain sizes
  • Utility fees
  • Building permit

Fees will vary from city to city. However, most city fees are fixed costs and will vary based on the size and valuation of your ADU. The average total cost of city fees is between $3,000.00 to $11,000.00.


ADU Construction Labor and Material Costs

When it comes to ADU construction labor, contractor fees will vary greatly depending on who you hire. One thing you should always remember though is you should never hire the cheapest ADU contractor. They likely lack the experience and expertise you need and will likely hit you with hidden fees later on.

As for the ADU material costs, you will find that experienced contractors in your area will often have deals with local suppliers to help cut down on these costs for you. It is also worth noting that your designs and material choices will greatly impact the overall ADU cost of this category.

What Influences ADU Construction and Material Costs?

ADU construction and material overall cost will be mostly influenced by various parameters like:

  1. Design and plans
  2. Structure type
  3. Size
  4. Conditions of property
  5. Conditions of the existing structure (if it is a garage conversion)
  6. Distance and location of utility connections
  7. Cost of materials (rough and finish)

The larger the ADU, the more expensive it will be. However, the bigger the size of the ADU, the cheaper your cost per square foot will be. For example, a detached 1,200 square foot unit is likely to be cheaper per square foot than a 400 square foot unit.

Although, if you plan on building a second story, it is going to be more expensive and can increase the ADU cost per square foot by up to 50%. Keep this in mind before deciding whether you need that second story. You can also check out our free ADU Guidebook for more information on contractors and construction.

Calculating Your ADU Construction Labor and Material Costs

On average the cost of building a conversion ADU is between $175.00-$225.00 per square foot. If you plan to build a new construction ADU, you can expect to pay anywhere between $250.00 to $300.00 per square foot for construction labor and material.


ADU Finish Materials Costs

Budgeting for your ADU finishing materials is key. They are what bring a decorative, nice look to your almost finished ADU. A few finish materials you will need include:

  • Flooring
  • Doors
  • Windows
  • Cabinetry
  • Tile
  • Stone

On average, finish materials will cost you anywhere from $50.00 to $75.00 per square foot.

You can learn more about budgeting for finish materials as well as the other aspects of each category in greater detail with this ADU Development eCourse: ADUeCourse. You will find countless helpful and in-depth videos with free bonus resources to help you with every step of the ADU building process.


Type Of ADU Effects Costs

The 2 main types of ADU are new construction and garage conversions. In most cases, a garage conversion will be cheaper by 20%-25% compared to a similar size new ADU construction. This is mainly because of the use of existing foundation, framed walls, and roof. However, how much cheaper also depends on the condition of those elements. If they are in bad shape, they will need to be replaced, which will increase your ADU cost.

So, if your garage is in extremely poor condition, don’t expect the ADU costs to be significantly lower than building a new construction one. Our free ADU Guidebook can help you understand the different types of ADU’s and the costs associated with them.


Total ADU Costs

To sum it all up for you, here is what the total average cost of your ADU can be.

Main Cost Category Average Price Range
Design And Planning $6,000 – $14,000
City Fees $3,000 – $11,000
Construction Labor And Materials $175 – $300 / Sqf
Finish Materials $50 – $75/Sqf

It is important to remember that ADU project costs are dependent on:

  • Project size
  • Various city fees applied
  • Project location
  • Design type
  • Existing garage condition of framing and foundation
  • The proximity of utility connections
  • Owner selection of finish materials

Therefore, what you choose will make a big difference in what you pay.

You should also keep in mind that all these ADU costs are averages. When coming up with your budget, you should take care to do your research and get estimates for all the jobs that will need to be done to get your ADU developed.

Additionally, once you have your total budget, it’s generally a good idea to give yourself some wiggle room with a bit of extra money in case things end up costing more than you originally anticipated. The last thing you want is for your ADU development to be put on hold or stopped because you are under-budgeted for something and now do not have enough money to finish it.

Total ADU Cost Examples

Looking at the above example, it can be hard to figure out what your total ADU cost overall will be when looking at the construction labor, materials, and finish materials because they are based on per square foot.

To give you a better idea of what your total costs can be, we have two examples below of a new construction ADU (499 square feet) and a garage conversion ADU (2 car garage) with their total costs. That way you can get an idea of what each type is going to actually cost you.

Main Cost Category New Construction 499 SQ ft 2 Car Garage Conversion
Design And Planning $8,000-$9,000 $6,000 – $7,000
City Fees $4,000-$5,000 $3,000-$4,000
Construction Labor & Materials $124,750 – $149,700 $63,000 – $81,000
Finish Materials $24,950 – $37,425 $18,000 – 27,000
Average Total Costs $161,700 – $201,125 $90,000 – 119,000

The new construction costs are based on a one-bedroom, one bathroom, 499 square foot ADU. ADU construction labor and materials are based on an average of $250-$300 per square foot.

For a 2-car garage conversion, ADU construction labor and materials will average around $175 – $225 per square foot. An average 2 car garage ranges from 300 square feet to 475 square feet. The above cost ranges reflect a 2-car garage that is 360 square feet.

ADU finish materials will still average around $50-$75 per square foot for both the new construction and the garage conversion. The above ADU costs reflect this.

It is important to remember that these are still just ADU cost estimates. The total cost of your ADU can vary greatly depending on your design and materials. But as you can see, garage conversions are often much more affordable than new construction ADUs. You can check out our free ADU Guidebook for more information on the different types of ADU’s and the costs associated with them.

ADU Size Matters

It is also important to note that the above new construction ADU is based on a 499 square foot example. An ADU is required to have a minimum living area of 150 square feet. Meaning new construction ADUs can be much cheaper than the above example. But they can also be much more expensive if they are the maximum 120 square feet.


Creating Your ADU Budget

Your costs will likely fall within the averages given above, but to get a better idea of your specific ADU costs, you can use our ADUCostCalculator. All you have to do is fill in information about your desired ADU and the calculator will give you an estimate right away of rough labor and materials.

You can also schedule a free consultation with us to give you a clearer idea of what goes into developing an ADU and whether your contractor estimates present a full picture.

Always Start with A Budget

One of the biggest ADU mistakes you can make is not creating your budget early on. Creating a budget will help you determine which type of ADU will work best for you. For example, we laid out the average ADU costs of a garage conversion versus new construction. Seeing the difference between the two can sway you one way or the other based on your needs.

A budget will also help prevent you from requiring any unnecessary ADU costs throughout the project because you know you need to stick to what you have allocated to each category. It helps you develop your ADU without spending way more than you need to by getting caught up in add-ons later on that you don’t need.

You can download our ADU eCourse to gain access to helpful budgeting sheets for each step of ADU development.

Don’t Let Your Contractor Set Your Budget

Many people hire an ADU contractor as their first step to create a budget for them without any designs, plans, or engineering in place. Don’t do this. You will be relying on a contractor’s blind ADU estimates and allowing them full control over your project. You should be the one in control.

With a contractor in charge, you will have no way to properly check and balance your ADU development. This could result in major overspending.

Don’t Cut Out ADU Essentials to Save Money

Another key aspect of budgeting your ADU is knowing where you can and where you cannot cut expenses. You should never make the mistake of trying to cut expenses by:

  • Not including a laundry area
  • Removing windows
  • Not planning for enough storage
  • Hiring the cheapest contractor you can find

Living in a dark, small unit that has no storage or laundry appliances, is not an ideal situation for most people. Plus, hiring the cheapest ADU contractor often results in hidden fees later on or poor quality of work.

If you are looking to cut down on your ADU expenses, you can do so by:

  • Opting for more affordable finish materials
  • Cutting down on square footage
  • Make it all-electric (no gas)
  • Have only one plumbing wall

Cutting down on ADU expenses during the budgeting phase should only be done when it won’t affect the quality of life of the people living in the ADU.


Don’t Forget About ADU Appliances and Furniture

Just like when you build a new home, you need to think about how much it is going to cost to furnish your ADU. With a new home, it can be easy because you can take furniture and appliances from your current home without problems. However, an ADU is tight for space, so you need to invest in new appliances and furniture that can fit within the given space.

These compact ADU appliances are key to making the most of your given space, but you need to ensure you think about the costs associated with them. No one wants to live in an unfurnished ADU with no kitchen or water heating.

You can check out our ultimate guide to ADU appliances and furniture for ideas on what your ADU might need, and how much it is going to cost you.


Start Building Your ADU Today

Here at Levi Design Build, we can help you budget out your ADU to keep your ADU costs down. If you are struggling to budget your ADU yourself, you can trust us to help while still allowing you the ability to check and balance your ADU project. That is because we don’t tie the design phase team into the build phase team. We keep everything separate to allow you the most control over your finances.

You can trust us to help you properly budget out every aspect of your ADU development process and then help you complete those processes. We offer a personalized approach to designing, planning, managing, and consulting on building your ADU. We also provide a free ADU Guidebook and amazing eCourse to help ensure your ADU development goes smoothly.

It is our commitment to provide you with the highest service throughout the entirety of your project, including the budgeting phase and managing your ADU costs.