How to Combine a First Mortgage and a HELOC Into One Conventional Loan

The Quick Read: You do not merge two loans into one. A new first-lien loan is originated, and its proceeds pay off both the old first mortgage and the HELOC at closing, leaving a single lien. On a rental property, that new loan is usually a DSCR cash-out refinance rather than a conventional agency loan, because it qualifies primarily on property-level rental income covering the payment, subject to lender guidelines.

• The combined payoff is the new loan amount. The rent has to cover the new, larger payment.
• Appraised value sets the ceiling. Cash-out files on standard rentals top out around 75% LTV across most of the network.
• Both liens must be paid off and the HELOC formally closed, or the new lender may demand subordination.
• A low legacy first-mortgage rate is the main reason not to do this.
• A DSCR above 1.00 does not mean positive cash flow. Exact terms depend on the lender’s guidelines, property type, leverage, and a full review of the borrower’s file.

The word “conventional” in the title deserves a plain correction. For an investor, conventional usually means an agency-conforming loan underwritten on personal income and debt ratios. That route exists, but it is the contrast case here. The mechanics below apply to the more common investor path, and the conventional version is covered briefly further down.

What Does “Combining” Actually Mean?

Combining means replacing two liens with one. The HELOC is a second mortgage, an open-end line you can draw, repay and draw again. The CFPB explains that a “second” mortgage is paid second if the home is sold to cover debts, which is why seconds often cost more than firsts.

So nothing gets merged. A new first-lien loan is sized to cover the first-mortgage payoff, the HELOC payoff and closing costs. The title company pays both old lenders from the proceeds. Any leftover goes to the borrower.

That makes it a cash-out refinance by structure, even if no cash comes back. The new loan carries a new balance, a new term and new terms of every kind. The old first mortgage’s rate and amortization are gone.

How Does Underwriting Treat It, Step by Step?

Underwriting treats the deal as a refinance of the whole debt stack. The lender looks at appraised value, the combined payoff, rent against the new payment, credit and reserves. Here is the sequence across most files we place through the wholesale network.

1. Size the payoff. Request a payoff statement for each lien. HELOC payoffs typically need a written request and a signed authorization to close the line. Interest is owed through the payoff date.

2. Order the appraisal. New value drives maximum leverage. The new loan must sit at or below the lender’s cap on that value, and for rentals the appraisal usually includes a market-rent opinion.

3. Run the coverage ratio. Divide monthly rent by the full monthly obligation on the new loan: principal, interest, taxes, insurance and any HOA dues. This is the new, larger payment, not the old first-mortgage payment.

4. Check credit and reserves. Most programs want a score around 660. A 620 floor exists in parts of the network, and 700 or better unlocks the strongest leverage tiers. Reserves commonly run around 6 months of PITIA, though they vary by lender, leverage, loan size and transaction type.

5. Close and pay off. The title company wires payoffs to both lenders. Confirm afterward that both liens are released.

Folding in a HELOC lifts the balance, and a bigger balance lowers the coverage ratio. That is the first thing to test. Rent that covered the old first mortgage comfortably may land close to the line once a drawn HELOC is added.

Clearing 1.00 is also not the same as healthy cash flow. The ratio counts only the payment bundle. Repairs, vacancy, management, utilities and capex sit outside it.

Which Leverage and Coverage Limits Apply?

On a standard rental cash-out refinance, most programs in the network cap at about 75% LTV, with about 6 months of seasoning the common expectation. Short-term rental collateral is tighter: cash-out tops out at 70%. Qualification on all of these is subject to lender guidelines and full file review.

On coverage, 1.00 is where many select programs start. A separate select-lender path takes coverage below 1.00, with leverage and terms adjusted. Stronger ratios open better pricing and leverage.

Loan sizes run up to $3,000,000 on standard programs (smaller balances available through select lenders). Above $2,500,000 the network generally holds to 30-year fixed structures. The spine of the product is the 30-year fixed, with 40-year terms and interest-only periods available through select lenders and ARM structures for investors who want them.

A bigger equity cushion helps the payment and the ratio. It never erases leverage caps, credit floors, reserve rules or property eligibility. The strongest files clear both tests: enough equity and enough rental coverage.

Which Path Are You On?

Combining is one of four routes. This table sorts them by what happens to each loan.

The last row is the quiet winner more often than investors expect. A very low first-mortgage payment beside a modest HELOC balance usually argues for leaving the first alone. A cash-out refinance reprices the entire balance, not only the HELOC portion.

What About Subordination?

Subordination is the alternative to payoff. If you refinance the first and keep the HELOC, the new first-lien lender insists on first position. That means the HELOC lender has to agree to move behind it. The HELOC lender is not obligated to agree, and a cash-out refinance is harder to subordinate because the first-lien balance grows.

If the cash-out pays the HELOC off at closing, no subordination is needed. That is why combining is often the cleaner route when the HELOC lender will not cooperate. Just make sure the line is formally closed. A HELOC left open after closing can leave a junior lien hanging over the new loan.

Where Does the General Rule Break?

Several edge cases change the answer.

Entity vesting. Many bank HELOCs will not lend to LLC-titled rentals. DSCR refinances often permit entity vesting, subject to program terms. If your HELOC sits on a personally titled rental that you later deeded to an LLC, the vesting question matters for the new loan.

Piggyback seconds. The CFPB defines a piggyback second as a HELOC or home equity loan made at the same time as the first mortgage, usually to avoid mortgage insurance on a low down payment. On agency loans these are often treated differently from equity drawn later. DSCR lenders set their own treatment, so a piggyback payoff may not behave the way it would on a conventional file.

Agency contrast. On a conventional file, Fannie Mae’s subordinate-financing guidance classifies refinances by what happens to the second lien. Paying off a purchase-money second with no cash out can be treated as a limited cash-out refinance, while paying off a non-purchase HELOC generally converts the deal to cash-out. That label usually does not carry over to DSCR products, which price on their own guidelines.

A passing ratio can still fail. Rolling a large HELOC into the balance can pull coverage down enough to cap the loan size. If the HELOC funded a down payment or renovations elsewhere, that debt now rides on this rental’s rent.

Ineligible properties. Manufactured homes, log homes and barndominiums are not offered in the network’s DSCR programs.

Business-purpose investor loans are also reviewed differently from owner-occupied mortgages. A consumer right of rescission generally does not attach to rental collateral, and consumer disclosure timing rules do not drive a DSCR closing.

What Does the Investor Decision Look Like?

The decision turns on a few trade-offs. Run each one before committing.

Blended cost versus new cost. Compare what the first mortgage and HELOC cost together against the new loan, rather than the HELOC alone. A mortgage with a very low legacy cost makes combining expensive even when the HELOC is painful.

Variable versus fixed. HELOCs typically float, so payments move. A fixed-term DSCR refinance trades that uncertainty for a stable payment, which helps if the line is pricey or the draw period is ending.

Draw-period cliff. When an interest-only draw ends, repayment usually begins and the payment steps up. Refinancing into a long-term first can avoid that jump. An investor three years from the end of a draw has more room to wait than one six months out.

The cost side. Closing costs run higher on a cash-out refinance than on a HELOC because it is a new first mortgage. The amortization clock also resets, and the new loan may carry a prepayment term.

Personal debt ratios. A DSCR refinance shifts qualification from the borrower to the property. That helps investors with many mortgages or complex income. It does not remove credit, reserve and equity requirements, and these loans are generally recourse.

Picture an investor with a rental carrying a modest first mortgage and a HELOC drawn to buy the next property. The rent covers the first comfortably, around 1.4x. Roll in the HELOC, and coverage might fall toward 1.1x. It clears a 1.00 floor, but the margin for a vacancy or repair spike is thinner. That is the trade, and it is worth sizing before ordering the appraisal.

What If You Wanted a Conventional Loan Instead?

An agency refinance of the combined balance is possible for borrowers whose personal income and debt ratios support it. It tends to suit an investor with one or two financed properties and clean traditional employment income. Once the portfolio grows or income gets complicated, the conventional lane narrows, and the property-income route becomes the practical one. Lendmire’s DSCR loans guide walks through how that comparison usually plays out.

What Else Is Worth Knowing About a HELOC Instead?

If the real goal is to pull equity without touching the first mortgage, a separate line may fit better. Investment-property HELOC lines cap at $500,000 total, and there is no tier above it. For the opposite problem, there is a piece Paying Down a Rental HELOC vs Rolling It Into a New First Mortgage.

Key Terms Defined

Cash-out refinance: A new first mortgage larger than the old one, with the difference paid to the borrower or used to retire other debt.

HELOC: A home equity line of credit, an open-end second mortgage you can draw, repay and draw again.

DSCR: Debt service coverage ratio, monthly rent divided by the full monthly obligation of principal, interest, taxes, insurance and HOA dues.

Subordination: An agreement in which a junior lender agrees to stay behind a new first lien.

Seasoning: The time a borrower has owned the property or held the loan before a refinance qualifies.

Payoff statement: A lender’s written figure for what it takes to retire a loan on a given date.

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

If you are weighing a refinance that folds a HELOC into the first mortgage, Lendmire, a broker arranging DSCR financing through select lenders across 41 markets including Washington, D.C., can help you compare structures based on the property, equity, credit profile and your goals. The calculator on the site offers an illustrative estimate only.

About Lendmire

Lendmire — NMLS# 2371349 — is a mortgage broker that arranges home equity lines of credit in its 16 full-service states through wholesale lenders, on primary residences, second homes and investment properties. Every line is subject to the lender’s guidelines and full underwriting. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. CFPB – What is a second mortgage loan or junior lien?

2. CFPB – What is a piggyback second mortgage?