ADU financing in California: HELOC vs RenoFi vs construction loan

Most home-improvement lending underwrites to your current equity. ADUs break that model because the unit you're building adds 25–35% to your home's appraised value — so financing the project against today's equity leaves real money on the table. Freddie Mac's underwriting framework explicitly contemplates ADU value-add Freddie Mac ADU appraisal guidance, and HUD's research backs the appraisal logic HUD ADU research.

For LA specifically, the stakes are higher because the value uplift is larger. UCLA Lewis Center's regional ADU research has documented appraised-value gains in LA neighborhoods UCLA Lewis Center ADU value research.

A home equity line of credit gives you a revolving draw against current equity, usually up to 80–85% combined LTV. Rates are variable, tied to prime, and as of early 2026 are running 8.0–9.5% for prime borrowers. The Consumer Financial Protection Bureau publishes the standard HELOC disclosure framework — read it CFPB HELOC guidance.

Best fit: smaller projects ($75K–$200K), homeowners with significant existing equity, and people who want fast access (often 14–21 days to close) without restructuring their first mortgage.

A cash-out refi rolls a new larger first mortgage over your existing one and hands you the difference. It's cheap money if you're refinancing into a lower rate anyway, but as of 2026 most LA homeowners have rates well below current market — making the math unfavorable.

Fannie Mae's HomeStyle Renovation product Fannie Mae HomeStyle Renovation is one of the few mainstream programs that lets you finance to as-completed value via a refi — worth comparing if you're set on a single-loan structure.

A construction loan disburses in draws as work completes, then converts to a permanent first mortgage at the end. Underwriting is to as-completed appraised value, which for an ADU project routinely unlocks 50–80% more borrowing capacity than a HELOC.

Tradeoff: more paperwork (the lender wants stamped plans, a fixed-cost contractor agreement, and a draw schedule), and a slower close — usually 45–75 days. The Mortgage Bankers Association tracks construction loan volume and rate trends Mortgage Bankers Association research.

RenoFi pioneered a HELOC structure underwritten to after-renovation value, sitting between a vanilla HELOC and a full construction loan. You get larger draws than a standard HELOC, faster close than a construction loan, and you don't restructure your first mortgage. Bankrate has covered the model in detail Bankrate — home equity coverage.

Best fit: homeowners with a sub-5% first mortgage they don't want to touch, who need $200K–$500K, and who want a single closing. Rates run 1.0–1.5% above standard HELOC.

California's CalHFA ADU Grant Program offered $40,000 toward predevelopment costs — it ran out of funding in 2024 and has not been refunded. Verify current status before counting on it CalHFA ADU Grant Program status. Some LA County housing agencies have launched smaller pilot programs; the LA Times has tracked these LA Times — housing finance coverage and AARP maintains a clearinghouse for state-by-state ADU finance programs AARP ADU resource center.