ADU
construction loans

Overview

This guide covers financing for accessory dwelling units — including how these programs work, what lenders look for, and how to get started. Qualification requirements vary by lender and program type. All loan programs are subject to credit approval and lender-specific criteria.

• Program availability varies by lender
• Qualification requirements vary by scenario
• Multiple program types available
• Speak with a licensed MLO for your situation

Getting Started

JumboLoan.com works with wholesale and portfolio lenders to provide access to programs not available at retail banks. Start our AI-assisted application or call us to discuss your scenario — a licensed MLO will identify the programs best suited to your situation.

• Start at AIMortgageApplication.com
• Licensed MLO reviews your scenario
• Multiple programs compared simultaneously
• NMLS# 1967971 — verify at NMLSConsumerAccess.org

Financing an accessory dwelling unit

ADUs — backyard cottages, garage conversions, attached in-law suites — are the fastest-growing construction category in America, and financing them is easier than most owners expect because the collateral already exists: your home. The main structures, in rough order of prevalence: a HELOC or home-equity loan (fast, no draw administration, sized against current equity — ideal when equity comfortably covers the $150K–$400K typical ADU budget); a cash-out refinance (replaces your first mortgage — compelling only when your current rate is at or above market); a renovation construction loan (sized against the as-completed value including the ADU — the answer when current equity is thin but the finished project appraises well); and construction draws against other assets for owners who prefer not to touch the house at all.

The underwriting questions specific to ADUs

• Will the ADU's value appraise? Appraisal treatment of ADUs varies by market maturity — areas with established ADU sales support value cleanly; pioneers should expect conservative numbers.
• Does rental income count? Increasingly yes: several programs now credit projected ADU rent toward qualifying, with rules about lease documentation and haircuts — a placement question that can transform affordability.
• Is it legal? Zoning, permitting, and (in Florida) local ADU ordinances decide whether the unit is a financeable improvement or an unpermitted liability; lenders and appraisers check.
• Detached vs. attached: detached new structures look like small construction projects (site work, utilities, impact fees); conversions of existing space budget lighter and finance more simply.
• Insurance and taxes move: the completed ADU raises assessed value and premiums — put both in the plan.

Total-cost honesty matters at this scale: utility connections, impact fees, and site work routinely add 20–30% to naive ADU budgets.

Choosing your ADU financing

The decision usually reduces to one comparison: equity-based borrowing (HELOC/home-equity loan — fast and simple, but capped by today's equity and priced at today's second-lien rates) versus as-completed renovation lending (more process, but sized to the finished value and often the only path for thinner equity). The tiebreakers are your first-mortgage rate (protect a low one — avoid cash-out), your budget size relative to equity, and whether rental income needs to help you qualify. We run that comparison — including which programs credit ADU rent — as a standard first step. Licensed broker, NMLS# 1967971.

Can an ADU be financed at the same time as buying the house?

Yes — purchase-renovation programs fund acquisition plus the ADU build in one loan sized on the as-completed value, a structure increasingly popular with buyers planning rental income from day one. The ADU plans and budget join the purchase underwriting, and the timeline runs like any renovation loan.