Construction financing options
You can fund building projects with a construction loan (funds released in stages), a construction-to-permanent loan (converts to a mortgage when done), or by tapping existing equity with a cash-out refinance or HELOC for smaller ADU projects.
California’s ADU-friendly rules have made backyard units popular for rental income or family space. The right financing depends on project size, your equity, and whether you want one loan or a draw-based construction facility.
Choosing your path
Large builds suit a construction or construction-to-permanent loan; smaller ADUs may be cheaper to fund with home equity. We’ll compare the options and structure financing around your timeline and budget.
The three ways to finance an ADU
Most California homeowners fund an ADU one of three ways. First, a cash-out refinance replaces your existing mortgage with a larger one and hands you the difference — simple and often the lowest rate, but it resets your first mortgage, so it only makes sense if today’s rate is close to yours. Second, a HELOC or home equity loan is a second lien that keeps your low first-mortgage rate untouched while giving you funds for the build — ideal when you locked a great rate years ago. Third, a dedicated renovation or construction loan underwrites the project based on the home’s after-completion value, which can unlock more money than your current equity alone supports.
Construction loan vs. tapping existing equity
The right choice hinges on your equity and the project size. If you already hold enough equity to cover the build, tapping it with a HELOC, home equity loan, or cash-out is usually faster and cheaper — fewer inspections, no draw schedule, and one closing. If the ADU is large relative to your equity, a construction-to-permanent loan may be the only option that pencils, because it lends against the property’s projected value once the unit is finished. The trade-off is a more involved process: staged fund draws, inspections at each phase, and conversion to a standard mortgage at completion. We model both paths so you see the true cost and cash flow before committing.
What California’s ADU rules mean for your loan
California has steadily loosened ADU regulations to encourage housing — streamlined permitting, reduced parking requirements, and limits on how much cities can restrict them. For financing, the practical upshot is that a well-planned ADU can add rental income and property value, and some lenders will count projected ADU rent to help you qualify or to size a larger loan. Building codes, setbacks, and utility connections still vary by city, so the financing and the permit plan need to move together. We coordinate the loan structure around your project timeline so funds are available when each phase needs them.
Frequently asked questions
How do construction loans work?
Funds are released in stages as the build progresses; a construction-to-permanent loan then converts to a standard mortgage.
Can I use projected ADU rental income to qualify?
With some programs, yes — a portion of the appraiser’s estimated market rent for the finished ADU can help you qualify or support a larger loan. We’ll match you to a lender that credits ADU income.
Is a cash-out refinance or a HELOC better for an ADU?
If your current mortgage rate is low, a HELOC or home equity loan preserves it while funding the build. If you’d refinance anyway or need a larger sum, a cash-out can be simpler. We compare both on total cost.
Can I fund an ADU with home equity?
Often yes — a cash-out refinance or HELOC can be a simpler, cheaper path for smaller ADU projects.
Which is right for me?
It depends on project size and your equity. We’ll compare construction financing versus tapping equity.
Save Financial, Inc. — NMLS #377740, DRE #01875766. Equal Housing Opportunity. Figures are illustrative for 2026 and not an offer of credit or a guarantee of rates or approval.