What’s Happening
Building an ADU typically costs anywhere from $80,000 to $400,000 or more, depending on the type of unit, your lot, local permit requirements, and whether you’re going prefab or site-built. That range is real, and the wide spread isn’t a dodge – it reflects how much the variables actually matter. A backyard studio conversion is a very different project from a fully detached two-bedroom unit with its own entrance and utilities.
If you just typed this question into Google, you’re probably at the beginning of figuring out whether an ADU makes sense for your property. Maybe you want a rental unit, space for a family member, or a home office that doesn’t eat up your backyard. Whatever the reason, the cost question is the right place to start – and the honest answer is that you won’t get a real number until someone walks your lot, reviews your local codes, and puts a written price in front of you. That’s exactly what we do.
Why It Happens – Why ADU Costs Vary So Much
1. The Type of ADU You Choose
A garage conversion costs far less than a new detached unit built from the ground up, because the shell already exists. A prefab unit from a manufacturer like Abodu, Dvele, or Mighty Buildings often comes in faster and at a lower per-square-foot cost than a fully custom site-built structure, but not always – it depends on your lot’s access, utility connections, and foundation requirements. The first thing to nail down is which type actually fits your property.
2. Site Conditions and Utility Connections
Two identical ADU floor plans can cost $40,000 apart if one lot has utilities running close to the build site and another requires trenching across a long yard or upgrading an electrical panel. Slope, soil type, and drainage all affect the foundation work. A flat, well-positioned lot with modern utilities is the cheapest scenario. A sloped lot with an aging service line is the expensive one – and you won’t know which you have until someone assesses it in person.
3. Permit and Code Requirements
Permitting rules vary significantly by jurisdiction. Some areas have streamlined ADU approval processes specifically to encourage more housing. Others require design review, setback variances, or additional inspections that add time and cost. These aren’t optional, and they’re not uniform. Your local Lodgewick ADU Builders team knows the permit landscape in your area and builds those requirements into the written price upfront – no surprises at the back end of the project.
4. Materials and Finish Level
An ADU finished with James Hardie fiber cement siding and engineered hardwood floors costs more than one finished with vinyl siding and laminate. Neither is wrong – it depends on what you’re building it for. A long-term rental that needs to hold up to wear is a different spec than a guest house you want to match your main home’s aesthetic. Finish choices can swing the final number by tens of thousands of dollars on a mid-size unit, which is why we walk through this with you before anything is quoted.
What to Do Right Now
- Write down what you actually want to use the ADU for. Rental income, in-law suite, home office, or something else – the intended use shapes the type, size, and finish level, which shapes the price.
- Measure your backyard or garage. Know the rough square footage you’re working with before a conversation starts. Even an approximate number helps.
- Find your property survey if you have one. Setback requirements – the minimum distance from your property line – will determine where an ADU can legally sit on your lot. A survey helps confirm this early.
- Note any obvious site conditions. Is the yard sloped? Is there an existing structure being converted? Are utilities clearly accessible? These are the questions that most affect cost, and having a sense of them before the estimate makes the conversation faster.
- Call your local Lodgewick ADU Builders team to schedule a lot walkthrough. The written estimate comes after someone has actually seen the property – not before. That’s the only honest way to price this kind of project.
How We Fix It – How We Build Your ADU
When your local Lodgewick ADU Builders team arrives for the walkthrough, we assess the lot conditions, discuss the type of unit that makes sense for your goals, and review permit requirements for your jurisdiction. From there, we put together a written, line-item price – before any work starts, every time. That’s not a policy we apply to big projects; it’s how every single job works at Lodgewick, per the Kingswell Way.
Depending on what fits your lot and budget, we can build using prefab solutions from manufacturers like Boxabl, Plant Prefab, Cover, or Tuff Shed, or handle a full site-built addition or garage conversion with James Hardie materials where exterior durability is the priority. Our Home Addition and Garage Conversion services cover the full scope – design coordination, permitting, construction, and finish work.
Every Lodgewick project is covered by the 365-Day Done Right Promise: if something isn’t right, we come back and make it right. That commitment is in writing before the first nail goes in.
Frequently Asked Questions
Most ADUs fall somewhere between $80,000 and $400,000, with the final number depending on unit type, lot conditions, local permit requirements, and finish level. A garage conversion is typically at the lower end; a fully detached, site-built unit with custom finishes is at the higher end. The only way to get a number that applies to your specific property is a written estimate after a lot walkthrough – which your local Lodgewick ADU Builders team provides at no charge. Call (254) 602-5618 to set that up.
Prefab units from manufacturers like Abodu, Dvele, or Mighty Buildings can reduce build time and sometimes cost, but they’re not automatically cheaper once you factor in site prep, foundation work, and utility connections. On a straightforward lot with good access, prefab often wins on speed and price. On a complex lot, the site work can offset the savings. We’ll walk you through both options and give you a written price on whichever direction makes sense for your property.
ADU projects involve permitting, design coordination, and site prep – they’re not same-day jobs, and anyone who tells you otherwise is setting you up for a bad experience. What we can do is get the process started quickly: a lot walkthrough, a written estimate, and a clear project timeline before any work begins. The sooner you call (254) 602-5618, the sooner your local Lodgewick team can map out a realistic schedule for your build.
Not from our side. Every Lodgewick project starts with a written price, and that price doesn’t change at the door or partway through the job. That’s one of the four commitments in the Kingswell Way: say the price before the work. If you have concerns about scope creep or mid-project surprises from past experiences with other contractors, that’s exactly the kind of thing our upfront written estimate is designed to protect you from. Call (254) 602-5618 and we’ll put it in writing before anything starts.
Get It Fixed
Your local Lodgewick ADU Builders team is ready to walk your lot and put a written price in front of you – no cost, no obligation. Call (254) 602-5618 to schedule your free estimate, or book online. A live person picks up every call, any time of day.
Written by Russ Delmar, Owner at Lodgewick ADU Builders, serving homeowners nationwide through the Kingswell family of home-service companies, established 2010.
What Our Customers Say
"A whole backyard ADU from scratch. Terrified me going in, but they kept me updated weekly and there were no nasty surprises. Quality work and a fair price."
- Noreen Fletcher"Built a backyard unit for my mother in law. They handled the permits, gave me a real timeline, and stuck to it within a few days. The written price is what we paid, which anyone who's done construction knows is rare."
- Dennis Fairchild"Garage conversion into a studio for our teenager. Honest about what was realistic and what wasn't, finished close to schedule, and cleaned up the site daily."
- Marcus Beaumont