How to underwrite a value‑add multifamily deal step‑by‑step: rent roll adjustments, unit-level capex phasing and pro forma stress tests

I underwrite dozens of value‑add multifamily deals a year, and the process often looks simple on a pitch deck and messy in the spreadsheet. If you want to convert a marketing brochure into a realistic pro forma, you need to interrogate the rent roll, model unit‑level capex with realistic phasing, and run stress tests that show how robust returns are to vacancy, rent growth, and economic cycles. Below I walk through the practical, straight‑forward steps I use — the same approach I teach investment teams and use for my own models.

Start with a clean rent roll: what to look for and why

The rent roll is your primary source of truth for current income and near‑term upside. But it’s full of traps: outdated leases, below‑market concessions, and in‑place rents that don’t reflect market comps. I approach the rent roll with three goals: validate current income, quantify near‑term upside, and isolate transient items.

Reconcile occupied units to on‑site management records and property inspection. Missing units or misclassified vacancies wreck your NOI projection.

Identify and tag any concessions (free rent, discounted months) separately. I convert concessions to a monthly income shortfall and amortize over the lease term so I can remove them from “normalized” rent assumptions.

Flag corporate or subsidized units. These often have below‑market rents and longer renewals, and they deserve separate treatment when forecasting turnover and achievable rents.

Compare in‑place rents to market comps at the unit level — bedroom count, square footage, and unit condition. I use local MLS searches, CoStar where available, and site visits to collect comps.

Example adjustment: a one‑bed unit lists at $1,100 but is reporting $900 due to a 3‑month free rent concession on a 12‑month lease. I treat the concession as a $200/month reduction over the year and show both “reported” and “normalized” rents in the pro forma. Normalized rent = reported rent + concession amortization.

Unit‑level capex phasing: build your rehab schedule like a project manager

Value‑add is delivered at the unit level. A realistic capex model is not a single “turn” number; it’s a phased schedule tied to turnover rates, work scope, and contractor capacity. I model capex by unit type and by phase (interim touch vs. unit rehab vs. full renovation).

Segment capex into categories: turnover work (paint, flooring, minor repairs), intermediate upgrades (appliances, cabinets, fixtures), and full unit rehabs (kitchen, bath, mechanicals).

Estimate per‑unit costs for each category. I collect vendor quotes and local crew rates — typical ranges vary greatly by market. For instance, turnover work might be $800–$1,500/unit; intermediate upgrades $3,000–$6,000/unit; full rehabs $12,000–$30,000/unit depending on scope.

Phase the work based on realistic turnover assumptions. If historical turnover is 50% annually, you can’t renovate 100% of units in year one. Instead, allocate a portion each month/quarter consistent with turnover and the property’s leasing velocity.

Model capacity constraints. Renovating 50 units a month requires multiple crews and working capital. Show the contractor capacity in the model and the timing impact on revenue uplift.

Here’s a simple capex phasing table I use to represent a 200‑unit asset with 40% annual turnover:

Capex Type	Per Unit	Units/Year 1	Units/Year 2	Units/Year 3
Turnover Touch	$1,200	80	40	40
Intermediate Upgrade	$4,000	20	40	20
Full Rehab	$18,000	10	15	15

Link cost outflows to timing and to rent lift assumptions — don’t assume instant, full rent capture the month a renovation completes. Typical lease‑up and marketing lag is 30–90 days. I tie rent lift to the unit’s next leasing event (renewal or turnover) and apply a ramp if the market takes time to accept new, higher rents.

Modeling rent lift: realistic assumptions and sources

Rent lift drives the value in a value‑add strategy, but it’s often overestimated. I use a three‑input approach:

Market achievable rent — derived from comps and new lease activity; treat this as the long‑run target for renovated units.

Renovated unit yield — how much of the gap between in‑place and achievable rent is captureable on the first lease. In many markets you capture 70–90% on first release; in weaker markets it’s lower.

Lease timing and rent escalation — new leases typically start at the move‑in date; I amortize uplift based on expected vacancy and marketing days.

Example: In‑place rent $900, market comparable for a renovated one‑bed $1,300. If I assume 80% capture on first lease, the first leased rent = $1,040. I then assume annual rent growth of 3% thereafter for pro forma projections.

Pro forma structure: revenue, expenses, and NOI timing

Structure your pro forma to show both “as‑is” and “stabilized” scenarios, with a clear bridge. I include:

Reported income (per rent roll) and normalized income (after removing concessions).

Vacancy & bad debt — model both economic vacancy (market vacancy rate) and loss to lease separately.

Other income line items — parking, laundry, storage — adjust for project‑specific changes (e.g., converting storage to rentable units).

Operating expenses — split fixed vs. variable. Many expenses will scale as occupancy increases (utilities, turnover costs), while property taxes and insurance are more fixed.

Keep a sensitivity tab that links key assumptions (vacancy, rent growth, capex schedule) to NOI and cash flow. A quick sensitivity matrix is one of the best ways to communicate risk to stakeholders.

Stress tests and downside scenarios: the true acid test

Stress testing separates robust deals from speculative ones. I run at least three downside scenarios in addition to the base case:

Soft market: rents compress 5–10% from projected achievable rents, vacancy increases by 2–4 points, and turn times lengthen by 50%. This scenario tests leasing sensitivity.

Capex overrun: construction costs +20% and schedule slips push rehab completion into year two. This checks liquidity and IRR sensitivity.

Macro shock: a 12‑month rent freeze or negative rent growth of 3–5% combined with a higher interest expense if debt reprices. This is harsher but helps you understand refinancing risk.

For each scenario I show the impact on cash flow, DSCR (if debt is in place), exit cap rate sensitivity, and IRR. A deal that fails modest stress tests is rarely worth pursuing; a deal that survives them with acceptable returns is the one I move forward with.

Tools and practical tips

My spreadsheet starts in Excel but I often import rent roll data from Yardi or Buildium to avoid manual entry errors. For complex multi‑year leasing and renovation schedules I use tabbed worksheets: rent roll, market comps, capex schedule, income statement, debt schedule, and sensitivities. I also keep a source‑of‑facts document that logs where every assumption came from — vendor quotes, broker comps, or on‑site observations.

Use unit IDs consistently across tabs so you can trace a single unit’s revenue and cost from rent roll to capex to pro forma.

Document conservative and aggressive assumptions side by side. Stakeholders like to see both.

Keep a rolling cash flow for construction draws and tenant turnovers. Shortfalls during renovation are the most common reason deals collapse.

Underwriting value‑add multifamily properties is about marrying realistic operational assumptions with tight project management. When rents are uncertain, my emphasis shifts to timing and liquidity: can you weather the renovation period and hold long enough for market acceptance? If the numbers survive a range of realistic stresses, you’ve got a deal you can defend to investors and lenders — and more importantly, one you can execute in the real world.