HELOC vs Home Equity Loan to Build an ADU on a Texas Homestead

The Quick Read: A HELOC fits an ADU build with uncertain costs and staged contractor payments, and a closed-end home equity loan fits a fixed contractor price, but on a Texas homestead both products sit under the same combined loan-to-value ceiling, the same advance-notice requirement, and the same one-lien-at-a-time rule. Choosing between them is mostly about cash-flow shape, not eligibility.

• Texas treats both products as the same kind of homestead lien, so the legal gate does not change with the product.
• A Texas homestead line on this network generally caps at 80% combined loan-to-value, and 80% is reachable only at roughly a 640 credit score or better. A line above $500,000 is capped lower, at 75% CLTV.
• Neither product counts the ADU’s future rent toward qualifying. Rental income matters only after the home stops being a homestead.
• Either product occupies the single Texas homestead equity-loan slot, so a second one, including a cash-out refinance, has to wait.
• If the owner moves out and the home becomes a rental, a DSCR loan is one option to explore. Final terms depend on lender guidelines, property type, leverage, and the borrower’s complete credit picture.

The honest answer on who each is for: the HELOC suits an owner whose build has phases, change orders, or permit-driven delays. The home equity loan suits an owner with a signed fixed-price contract who wants one funding event and one repayment schedule. Neither suits an owner who needs the ADU’s projected income to carry the loan.

Side-by-Side

The HELOC column below reflects the line programs Lendmire’s wholesale network places. The home equity loan column shows published industry norms, which vary by lender.

Both products are second mortgages if a first mortgage already exists, as the CFPB explains in its comparison. The agency describes the loan as a lump sum and the line as a balance you can borrow against multiple times up to a maximum.

Texas Rules That Apply to Both Products

Texas puts both products under the same constitutional framework. The Texas A&M Real Estate Research Center explains that these liens fall into three categories: cash-out refinancing, home equity loans, and HELOCs. All three sit under Article XVI, Section 50 of the Texas Constitution.

Four rules shape an ADU budget:

1. Homestead only. Section 50 loans may not be taken on a secondary residence or a rental or investment property. The owner must live in the home.

2. 80% combined cap. The borrower must keep at least 20 percent equity in the home. The existing first lien counts against the cap.

3. Advance written notice. The lender must give the borrower a separate written notice before closing. Build that waiting period into the construction schedule.

4. Consent of every owner and spouse. The lien must be voluntary and agreed to in writing by each owner and each owner’s spouse.

The value used for the cap is generally the home’s value when the loan is made, not the finished ADU’s future value. How a given appraisal or automated valuation treats planned improvements is a question for the lender before the budget is set. Plan the build against today’s equity.

Because the legal gate is the same, product choice changes three things: how funds arrive, how interest accrues, and how much payment risk sits in the construction period.

When a HELOC Is the Better Fit

A HELOC is the better fit when the build cost is not locked. Because the line can be drawn again after closing, later construction costs can be funded as they come due rather than all at once. That matters when a contractor bills by milestone or when permitting could delay the start.

The network’s lines use one of two draw structures. One runs a 3-year interest-only draw followed by a 17-year fully amortizing repayment. The other, the longer-runway program, runs a 5-year draw followed by a 25-year repayment. The longer runway gives an owner more time to finish construction, move in tenants if the home later becomes a rental, and settle into the amortizing period.

Three program details change the staged-build logic:

• Most of the line funds at closing. On both programs, at least 75% of the line is drawn at closing. A HELOC in this network therefore behaves partly like a lump-sum loan. Size the line to the real build budget, not to a large cushion, because the drawn portion starts costing money on day one.
• Texas draw minimum. The longer-runway program states a $4,000 minimum subsequent draw in Texas. Small draws for permits or deposits need to be bundled.
• Variable structure. Pricing on these lines floats through both the draw and the repayment period and does not convert to fixed. The owner should plan for the structure rather than treat it as a lump-sum loan with a fixed schedule.

Only the remaining portion of the line, no more than a quarter of it, stays available for later draws. A Texas homestead can carry only one Section 50 loan at a time, so that undrawn portion is the only way to reach further funds without a second lien.

Qualification runs on credit, equity, and debt-to-income. DTI maxes at 50%, drops to 45% for credit profiles from 600 to 679, and any ratio above 45% requires a 680 minimum. The payment is qualified on the interest-only amount at the maximum draw, so a large line can fail DTI even if the owner never draws all of it.

When a Home Equity Loan Is the Better Fit

A home equity loan is the better fit when the contractor price is fixed and the owner wants predictability. The full amount funds at closing and repays on a fixed schedule. The TRERC article notes that payments must be substantially equal and at least equal to the accrued interest.

The owner pays interest on the whole balance from closing. That costs more in a long build, but the structure removes draw management. There are no minimum-draw rules to plan around, and no temptation to use leftover line capacity on unrelated spending.

The closed-end loan also fits an owner who wants the ADU build separated from the home’s other borrowing. With one lump sum, the repayment schedule is known up front, and the owner can see how the new payment sits beside the first mortgage.

The weak point is cost overruns. A lump sum sized to a contractor bid has no room for change orders. In a Texas homestead, adding to the loan after closing means a new Section 50 loan, and that runs into the one-at-a-time rule. An owner with a thin contingency should either size the loan above the bid or choose the line.

What the Network’s Line Programs Require

These figures apply to lines placed through Lendmire’s wholesale network, each subject to lender guidelines and full file review. Lendmire brokers these lines in its 16 full-service states, Texas among them, and is never the lender.

On a Texas primary residence, the homestead cap is 80% combined loan-to-value, and no higher primary tier applies. The credit tiers that matter in Texas look like this:

• 640 or better: up to 80% CLTV, with a line up to $500,000.
• 620 or better: up to 70% CLTV, with a line up to $400,000.
• 600 or better: up to 60% CLTV, with a line up to $400,000.
• Above $500,000: primary residence only, 700 or better (720 on the longer-runway program), a 75% CLTV cap, and a full appraisal. The line maximum is $750,000.

Lines at or below $500,000 ordinarily run an automated valuation with no traditional appraisal, though a higher CLTV may require a secondary valuation, and the borrower can request a full appraisal in any case.

Property types include single-family homes, 2-4 units, PUDs, townhomes, and condominiums. Manufactured homes, log homes, co-ops, and condotels are not offered. The Texas acreage limit is 10 acres. A property listed for sale, or listed within the past 60 days, is ineligible in Texas.

Title matters. The individual borrower or an inter vivos revocable living trust must hold title. An LLC, corporation, partnership, or irrevocable, blind, or land trust cannot hold title. A homestead is held by natural persons anyway, but an owner who has deeded the property to an LLC would need a vesting change before a line is possible.

Texas also adds primary-residence rules that bind this network: a waiting period, the one-lien-at-a-time rule, and 12-month seasoning. Texas second homes and investment properties are eligible as non-homestead transactions, but an investment line tops out at 70% CLTV, requires a 700 credit profile, and carries a $500,000 maximum on the 5-year draw structure only.

Sequencing, Overruns, and the Rental Stage

Order matters more in Texas than in most states. Only one Section 50(a)(6) lien can sit on the homestead at a time. The constitutional notice states that only one loan under Section 50(a)(6) may be secured by the home at any given time. An owner who takes a line or loan for the ADU cannot later add a cash-out refinance on top of it, and the reverse is also true.

That leads to a practical sequence:

1. Settle the build budget with a signed bid and a contingency.

2. Confirm the combined cap leaves room for that budget after the first lien.

3. Choose the product that matches how the contractor bills.

4. Plan the rental-stage financing before taking the equity lien.

There is an alternative lien path for construction. Article XVI, Section 50(a)(5) permits a lien for work and materials used to construct new improvements when contracted for in writing, as Fasthoff Law Firm explains. Sandler Law Group adds that the contract is executed by the owner and the owner’s spouse at the office of the lender, a title company, or an attorney. Whether this path interacts with the one-at-a-time rule on a specific loan is a question for a Texas attorney, not a broker.

Compliance matters because a lender that misses a Texas requirement can lose the lien. The Supreme Court of Texas addressed the forfeiture remedy in Section 50(a)(6)(Q)(x) in a recent opinion, which says a lender who breaches the loan agreement may forfeit the entire loan amount under that remedy. Lenders know this, which is why Texas lines get careful closing procedures.

Overruns are the practical risk. If costs exceed the line or loan, the owner has three options: pay from cash, reduce the scope, or wait for the lien to be satisfied before borrowing again. The cap leaves no room to add a second equity lien.

Once the owner moves out, the home is no longer a homestead, and Section 50 products are no longer available on it. DSCR loans are designed for non-owner-occupied investment properties. Because they are business-purpose investor loans, they are reviewed differently from a standard owner-occupied mortgage.

For the rental stage, a DSCR loan is reviewed primarily on property-level rental income covering the payment, subject to lender guidelines. A 1.00 coverage ratio is where select programs start, and a separate select-lender path takes coverage below 1.00 with leverage and terms adjusted. Clearing 1.00 is not the same as positive cash flow, because repairs, vacancy, and management sit outside the calculation.

Lendmire’s DSCR HELOC vs. cash-out refinance comparison for an ADU covers that handoff in detail, and the complete DSCR loans guide explains how the rental-stage loan works. DSCR programs run across 41 markets, including Washington, D.C.

Mistakes That Derail These Plans

• Counting ADU rent. Neither product is reviewed on projected ADU rent. Debt-to-income and credit decide eligibility.
• Sizing the line too large. With 75% of the line drawn at closing on this network, an oversized line adds cost and DTI strain without helping the build.
• Ignoring local ADU rules. Permitting and owner-occupancy rules vary by city, and they should be checked against each city’s code before the budget is final.
• Assuming a cash-out refinance can follow. The one-lien rule and 12-month seasoning mean the order of borrowing is hard to reverse.
• Wrong vesting. A property deeded to an LLC cannot take a line until title is corrected.

Key Terms Defined

Homestead: the home an owner lives in, which Texas protects from forced sale and limits to specific lien types.

Combined loan-to-value (CLTV): all loans on the property added together and divided by its value.

Draw period: the stretch when a line allows borrowing and requires interest-only payments.

ADU: an accessory dwelling unit, a second living space on the same lot.

A Balanced Verdict

Choose the HELOC if the build is phased, the cost is not locked, or the owner wants to keep some equity unused. Choose the home equity loan if the contract is fixed-price and the owner values a known repayment schedule. In both cases, the 80% cap, the advance notice, and the one-lien rule decide the budget before the product does.

An owner whose plan depends on the ADU’s rent covering the loan has the wrong product. That plan belongs on a DSCR loan after the home stops being a homestead.

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. Every figure is subject to lender guidelines and not a commitment to lend.

About Lendmire

Lendmire is a mortgage brokerage (NMLS# 2371349) arranging home equity lines of credit — primary-residence, second-home and investment-property lines — through a wholesale lending network in its 16 full-service states. Eligibility is determined by the lender on each file. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. CFPB: Home equity loan vs. HELOC

2. Texas A&M Real Estate Research Center

3. Fasthoff Law Firm

4. Sandler Law Group

5. Supreme Court of Texas No. 24-1057