Does a Bank Statement HELOC Make Sense for an Accessory Dwelling Unit?

Building a backyard unit is a funding puzzle before it is a construction project. Self-employed owners hit it hardest, because tax returns often understate what the business really earns.

The Quick Read: Sometimes. It works best as a short-term bridge for a self-employed owner who has strong equity today, since a bank statement line changes only how income is documented, not how the line is sized or repaid. The line is measured against what the home is worth now, so an ADU that does not exist yet adds nothing to it.

• Income is proven through statements instead of tax returns, but the full file is still reviewed.
• The line sizes off current value, not the finished ADU or its future rent.
• Draws are interest-only first, then repayment, and pricing floats.
• Investment lines top out at 70% CLTV; primary-residence lines can reach higher with strong credit.
• Many owners plan a later DSCR cash-out refinance once the ADU is leased.

What Is a Bank Statement HELOC?

A bank statement HELOC is a revolving line of credit secured by your home. The lender reviews 12 to 24 months of personal or business bank statements instead of tax returns, then averages the eligible deposits. Scotsman Guide describes the standard scenario: a self-employed borrower with no W-2 provides statements, and the lender applies an expense factor to business deposits, with 50% as its example. Programs set their own factor, so treat that number as an illustration.

It is not a no-doc loan. Credit, existing debt, equity, and the property are all reviewed, and the borrower is reviewed on documented income under the applicable program, subject to lender guidelines.

Key Terms Defined

• Bank statement HELOC: a home equity line where deposits, not tax returns, document income.
• ADU: a second, smaller dwelling on the same lot, such as a backyard cottage or garage conversion.
• CLTV: combined loan-to-value, meaning the first mortgage plus the new line divided by the home’s value.
• Draw period: the stretch when you borrow and pay interest only, before repayment begins.
• DSCR: the ratio of a rental’s income to its full monthly housing payment.

Why the ADU Is the Awkward Part

A line sizes off the value of the property today. The CFPB booklet on HELOCs explains that credit limits are generally a percentage of the home’s appraised value, less what you owe. Nothing in that formula credits a unit that has not been built.

Rent from a planned ADU does not help either. Lenders on this type of file look at your documented income and the home’s current equity. Agency mortgages treat projected ADU rent differently, but those rules do not carry over to this line.

Value is also uncertain. An ADU may support a higher appraised value, depending on comps and underwriter review, but the lift often falls short of build cost. Plan the budget as if some of the spend will not come back as appraised equity.

How the Mechanics Run, Step by Step

1. Pick the statement window. Twelve to twenty-four months is typical, personal or business depending on where the income lands.

2. Clean the deposits. Transfers between your own accounts, loan proceeds, gifts, and refunds typically come out. Business deposits must be identifiable as business income.

3. Calculate income. Eligible deposits, reduced by the expense factor on business accounts, are averaged over the months reviewed. Partial owners are prorated to their share.

4. Test the file. Debt-to-income tops out at 50%, with 45% as the limit for credit profiles from 600 to 679. A ratio above 45% requires at least a 680 score. The test runs on the interest-only payment at the maximum draw.

5. Size the line. The ceiling depends on occupancy and credit, covered below.

6. Draw and repay. At least 75% of the line is drawn at closing on both structures. That front-loaded draw means interest accrues on money your contractor has not yet used.

7. Exit. Once the ADU is leased, many owners refinance into a DSCR cash-out loan and pay the line off.

The FTC notes that HELOCs typically carry a variable APR and that you pay only on what you borrow. On this network, pricing floats through both the draw and repayment periods and never converts to fixed.

What the Line Can Look Like

Across the wholesale network Lendmire places these files with, the ceilings depend on how the property is used.

Two details matter for ADU planning. On a primary residence, the 90% tier applies only at 720 or better and only up to a $500,000 line. A line above $500,000 is for primary residences only, requires 700 or better (720 on the longer-runway structure), caps at 75% CLTV, and needs a full appraisal. On a Texas primary residence, the cap is 80% combined. Figures are subject to lender guidelines and full file review.

Draw structures come in two forms on primary and second homes: a 3-year interest-only draw with 17-year repayment, or a 5-year draw with 25-year repayment. Investment lines use the 5-year draw and 25-year repayment only. Availability for this product is limited to Lendmire’s 16 full-service states, which is narrower than its DSCR footprint.

When It Fits, and When It Doesn’t

It fits when the owner is self-employed, has meaningful equity, and wants staged access to cash for a build. It also fits when the owner plans a refinance after lease-up and can carry interest-only payments in the meantime.

It fits poorly when:

• The only equity depends on the ADU’s finished value.
• Debt-to-income is already stretched by several mortgages. A DSCR cash-out can clear a file that a personal-income line cannot, since DSCR compares rent to the property’s full payment instead of the borrower’s income.
• The property is held in an LLC. These lines require title in the individual borrower’s name or a revocable living trust. A property already deeded to an LLC needs a vesting change, or a DSCR cash-out instead.
• The owner owns more than 15 financed properties, or already holds three lines.

The line itself is also at risk if values drop. The CFPB warns that a lender may stop further draws if the home’s value falls significantly, and that falling behind could cost you the home. On a build that runs several months, that matters.

How It Compares With the Alternatives

A DSCR cash-out refinance typically tops out around 75% LTV across most of the network, with about 6 months of seasoning common. It qualifies primarily on property-level rental income covering the payment, subject to lender guidelines. It also replaces your first mortgage, while a HELOC in second position leaves it intact. Keeping a favorable first mortgage can be the deciding factor.

If you are weighing a full replacement of the first mortgage, Lendmire’s piece Does a Bank Statement Cash-Out Refinance Make Sense to Build an Accessory Dwelling Unit? walks through that trade.

The Exit Plan: From Line to DSCR

Think of the HELOC as phase one. Phase two is a refinance once the unit is permitted, finished, and leased. Lenders on the DSCR side generally want the property rent-ready, since coverage is measured against documented or appraised rent. Clearing 1.00 on coverage is not the same as positive cash flow, because repairs, vacancy, management, and utilities sit outside the ratio.

Coverage of 1.00 is where many select programs start, and a separate select-lender path goes below 1.00, with leverage and terms adjusted. A larger down payment or lower balance can lift coverage, but it does not erase credit floors, reserve rules, or property eligibility. The strongest files show enough equity and enough rental coverage. For the full picture of how those programs fit together, see Lendmire’s complete DSCR loans guide.

Short-term rental use changes the math. Rules vary by city, county, HOA, and property type, so investors should confirm local rules before relying on projected rental income.

Before You Apply: A Short Checklist

• Gather 12 to 24 months of statements and keep business and personal deposits separate.
• Identify and explain large one-off deposits.
• Confirm the ADU’s permit status and that the lot supports it.
• Check your credit profile against the tier you need. The report must be no more than 90 days old at closing.
• Decide whether to keep your first mortgage or replace it.
• Confirm title is held in your name or a revocable trust.
• Define the exit: how long the build runs, when the lease starts, and what refinance follows.

Tax treatment can depend on how the funds are used and how the property is held; borrowers should keep clear records and speak with a qualified tax professional before relying on any deduction.

If you are considering a home equity line and want to see how the numbers work, Lendmire can help you compare HELOC options based on the property, the equity available, credit profile, combined leverage, and your goals. Reach the team at 828-256-2183 or request a quote.

About Lendmire

Lendmire (NMLS# 2371349) is a mortgage brokerage serving homeowners and real estate investors in its 16 full-service states. Home equity lines of credit are arranged through wholesale lending channels; Lendmire brokers the line and the lender underwrites each application under its occupancy-based guidelines. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. Scotsman Guide – Rev Up the Engine for Non-QM Lending

2. CFPB – HELOC booklet

3. FTC – Home equity loans and HELOCs