Financing an ADU is a decision you make with a lender, not with a builder. We do not arrange loans or recommend lenders. What we can do is explain how the common routes work from the project's side, what a lender will ask to see, and why the order of steps matters. That way you walk into the bank with the right documents and the right questions.
The common ways owners fund an ADU
Each route below has different requirements, and the right one depends on your equity, your income, your existing mortgage and how you plan to use the unit. A lender or a financial adviser is the right person to compare them for your situation.
Cash. The simplest route on paper. There is no lender involved, so no appraisal or draw schedule. The planning risk is running short partway through, which is why a written budget with clear exclusions matters even more here.
Home equity line of credit (HELOC). A revolving line secured by your home's existing equity. You draw what you need as the project moves forward. It works best when there is enough equity in the house today to cover the build, since the line is based on the current value, not the value after the ADU is added.
Cash-out refinance. You replace your existing mortgage with a larger one and take the difference in cash. It can make sense when the new loan terms suit you, but it changes your whole mortgage, not just the ADU portion. Compare the new terms against your current ones carefully.
Construction or renovation loan. Some loans are based on the expected value of the property after the work is finished. These are built for projects like an ADU, but they come with more paperwork and a structured draw schedule, because the lender pays out in stages as the work is completed and inspected.
A combination. Some owners use savings for the design and permit phase and a loan for construction. That split lines up well with how an ADU project is actually sequenced.
What a lender wants from the builder
Whichever route you choose, a lender financing construction will want to understand the project before releasing money. Expect to provide:
- A detailed written budget, broken down by line item.
- The contract with your licensed contractor.
- A set of plans, and often proof that permits have been applied for or issued.
- The contractor's license and insurance information.
- A schedule showing the stages of work.
For a loan based on the finished value, the appraiser also needs the plans and the scope to estimate what the property will be worth with the ADU in place. Vague plans make for a cautious appraisal.
Draw schedules and construction stages
Construction and renovation loans rarely pay the full amount up front. Instead, they release money in draws tied to stages: foundation, framing, rough mechanical inspections, drywall, finishes and final. Before each draw, the lender may send an inspector to confirm the stage is complete.
This affects your builder's payment schedule. A contract with payments tied to completed stages lines up naturally with a lender's draws. A contract with payments tied to dates on a calendar does not, and the gap between what is owed and what the lender has released can fall on you. When you compare builders, check that their payment schedule can follow the lender's draw schedule.
City inspections are a useful marker here. A signed-off foundation inspection or rough framing inspection is clear evidence for both the lender and you that a stage is done.
The last draw deserves its own line in your plan. Lenders often hold it until the city signs off on the final inspection, since that sign-off is what makes the unit legal to live in. If the builder's contract expects final payment before that point, you may need cash on hand to cover the gap. Line the two schedules up before you sign either one.
Plans first: why the design spend comes before the loan
Almost every financing route needs a defined project before money is committed, and a defined project means drawings and a written budget. That is why design usually comes before the loan, and why many owners pay for it separately.
There is also a planning reason. Until the lot is reviewed and the type of ADU is chosen, the cost is a guess. A detached unit at the back of a lot with a long sewer run and a garage conversion near the street can differ substantially in price on the same property. Settling that first means the amount you borrow is based on your real project, not an average.
At Cedarline, the first step is a lot review from our base in Woodland Hills, followed by drawings and a written budget broken into lines. That package is what a lender will ask for. You can read about how we plan units on the ADU construction page, and about room additions if you are comparing a unit with more space for the household.