Financing 5+ Unit Multifamily: Where Residential Rules End

Between a fourplex and a five-unit building sits one of the widest practical boundaries in real estate finance. Four units is residential: residential appraisal forms, 30-year products, the coverage conventions covered in /blog/dscr-loans-complete-guide. Five units is commercial: a different appraisal, a different definition of the coverage ratio itself, a different document stack, and a different set of lenders. Investors who cross the line expecting a slightly larger version of the familiar process meet a different industry instead. This article maps what actually changes. Scope: business-purpose lending on non-owner-occupied investment property.

The ratio changes definition

On 1-4 unit rentals, DSCR commonly means gross rent divided by the full PITIA payment, with operating expenses ignored. At five units and above, the commercial convention governs: net operating income — collections minus a vacancy allowance, taxes, insurance, management, repairs, and reserves — divided by annual debt service of principal and interest. The same building produces materially different ratios under the two conventions, and a residential-convention calculation on a commercial deal overstates coverage by the entire expense load, because it pretends operations cost nothing. If you use /tools/dscr-calculator or any other tool on a 5+ deal, confirm you are running the commercial convention, with the lender's expense assumptions rather than your own.

Underwriting runs on the operating statement

Commercial underwriting starts from documents small-residential lending never requests: a trailing-twelve-month operating statement and a current rent roll. Lenders then commonly normalize your numbers rather than accept them — applying a vacancy allowance even if the building is full, a management fee even if you self-manage, minimum expense loads where your actuals look thin, and per-unit replacement reserves inside the coverage math. The underwritten NOI is therefore commonly lower than your actual NOI, and arguing about the conventions is less useful than knowing them going in.

The appraisal changes with the underwriting. Instead of a form report driven by comparable sales, expect a commercial narrative report built primarily on the income approach — capitalizing the normalized NOI — supported by sales comparisons. It takes longer, costs more, and its assumptions about expenses and vacancy will echo the lender's rather than yours.

Mixed-use buildings sit near this boundary and follow their own rules. Lenders commonly cap the share of commercial space or commercial income a property can carry and still qualify under a given program, and a building over the cap moves to commercial products regardless of its unit count. If your five-plus building includes storefronts, ask where the lender draws that line before assuming any program fits.

Sizing: the coverage constraint usually binds

Residential intuition says the down payment sets the loan size. Commercial sizing commonly runs two constraints in parallel — a maximum loan-to-value and a minimum coverage ratio — and the loan is the smaller answer. When rates are high relative to rents, the coverage constraint binds first: the loan that satisfies the coverage floor on the normalized NOI can sit meaningfully below what the LTV cap would allow, and no additional down payment percentage changes that arithmetic — only more NOI or a cheaper rate does. Some lenders add further tests of the same family, such as a minimum debt yield, meaning NOI divided by the loan amount. Ask which constraints the lender runs and which one is binding on your deal; the answer tells you what the negotiation is actually about.

The lender menu

Banks and credit unions. Balance-sheet lenders and the natural home for much small multifamily: global underwriting of the whole borrower, often competitive pricing, and structures that frequently include balloons or rate resets rather than 30-year fixed terms. Recourse is the norm.

Agency small-balance programs. Both government-sponsored enterprises operate small-loan multifamily programs for stabilized properties, with program-specific boxes on loan size, markets, and coverage. Terms and eligibility change; current program materials are the only reliable source, and folklore about them ages badly.

Debt funds and bridge lenders. For value-add buildings that do not yet cover — the commercial version of the stabilize-then-refinance path, whose short-term mechanics and costs are mapped in /blog/hard-money-vs-bridge-loans.

Larger structures. Above the small-balance space sit CMBS and institutional executions with their own prepayment and reporting machinery — different territory, mentioned here only so you know where the map ends.

Recourse deserves its own note. Commercial loans are sometimes non-recourse with carve-out guaranties, under which acts like fraud or misapplication of funds convert the loan to full recourse. Non-recourse is not no-risk, and the carve-out guaranty is a document to read, not skim.

Reports, timelines, and deposits

Commercial closings run on a third-party report stack: the commercial appraisal, a Phase I environmental site assessment, and commonly a property condition assessment — borrower-paid, ordered after an application deposit, and measured in weeks. Overall timelines commonly run longer than residential DSCR closings, and the deposit is real money committed before certainty. Budget both, in cash and in contract dates.

Pricing language changes at the boundary too. Commercial quotes commonly arrive as a spread over a reference index rather than a flat number, with the rate set at or near closing, and fixed periods commonly run shorter than the amortization — which is exactly what creates the reset and balloon structures noted above. None of this is exotic once expected. But an investor comparing a commercial quote against a 30-year fixed DSCR quote is comparing different machines, not different prices.

A 5+ building held alongside 1-4 unit rentals also raises a structural question — one commercial loan on the building, or the building financed separately from a blanket across the small properties. The pooled-collateral mechanics in /blog/rental-portfolio-loans-guide are the right comparison set for that decision.

Common mistakes

• Running the residential coverage convention on a five-plus deal and overstating coverage by the entire expense load.
• Underwriting to your actual expenses when the lender will normalize vacancy, management, and reserves regardless.
• Forgetting per-unit replacement reserves in the coverage arithmetic.
• Reading non-recourse as risk-free without reading the carve-out guaranty.
• Budgeting no time or money for the third-party report stack.
• Ignoring the balloon or reset date because the starting rate looked familiar.

How to verify

• Ask the lender for its coverage convention and every normalization input in writing — vacancy allowance, management factor, expense minimums, reserves per unit — and recompute the ratio yourself before relying on anyone's quote.
• Ask for the third-party report list with costs, timing, and deposit refund terms before paying anything.
• Ask whether the loan is recourse, and read the carve-out guaranty itself rather than a summary of it.
• Confirm the structure end to end: fixed period, reset mechanics, balloon date, amortization, and prepayment provisions.
• For stabilized properties, ask whether agency small-balance programs fit your deal, and get current program terms in writing rather than relying on what those programs offered someone else last year.