To underwrite a mixed-use property, treat it as two or three small properties that share a roof: split the rent roll, operating expenses, reserves and leasing assumptions by use, give each use its own vacancy, rollover and market rent, then add the results and test the value two ways. The usual mistake is a single blended assumption that lets strong apartments hide weak ground-floor retail.
Updated 19 October 2026.
Published by Titleman, which makes underwriting software.
Written by the Titleman team with AI assistance (Claude). This page is about underwriting for an investment decision. It is not an appraisal.
Why mixed-use is its own problem
A typical building has apartments over shops, or offices over retail. The uses differ in almost every input that matters:
| Input | Residential | Ground-floor retail | Office |
|---|---|---|---|
| Lease length | About one year | Often five to ten years | Often three to ten years |
| Expense recovery | Usually none beyond utilities | Often net, with CAM | Base year or net |
| Downtime when vacant | Weeks | Often many months | Often many months |
| Re-leasing cost | Turnover and marketing | Tenant improvements, commissions, free rent | Tenant improvements, commissions, free rent |
One blended vacancy or one blended reserve across those columns is not an assumption, it is an average of different risks.
The order that saves time
- Split the rent roll by use. Tie each commercial tenant to its lease: rent, step-ups, expiry, options and any CAM terms. Residential units are checked as a group for in-place rent against market.
- Split the T-12 by use. Use meters and the commercial leases where they allow it, and floor area where they do not. This tells you which costs the owner keeps.
- Assumptions by use. Each use gets its own vacancy, market rent, renewal probability, downtime and re-leasing cost.
- Reserves by use. Restaurant exhaust, storefronts and residential kitchens wear on different cycles. Build the replacement reserves from the property condition assessment, by use where the report allows.
- One NOI, two values. Add the NOIs. Capitalise the total at a cap rate from comparable mixed-use sales, and separately capitalise each use at its own rate. A large gap between the two is a question, not a rounding error.
- Debt on the weak part. Check coverage with the commercial space at a stressed occupancy, because that is how many lenders will look at it.
A short worked example (illustrative figures)
Not a real property. Apartments produce USD 600,000 of NOI and the ground-floor retail USD 200,000. At 5.5% and 7.0% separately, the parts are worth about USD 10.9 million and USD 2.9 million, USD 13.8 million together. A blended 6.0% on USD 800,000 gives USD 13.3 million. The gap of about USD 0.4 million is the market's view of how much the retail drags on the whole building: worth knowing before you agree a price.
Where software helps and where it stops
A mixed-use underwriting is mostly reading: leases, a rent roll, a T-12, a PCA. When Titleman builds one from the offering memorandum, rent roll and T-12, the output is a memo and a live Excel model with a 10-year pro forma, debt, returns and sensitivity grids, where every input shows its source and date and every result shows its formula. The median run takes about 60 minutes. The memo gives no final price or buy verdict, results vary between repeat runs, and a figure we could not find is named as missing rather than filled. It does not replace a licensed appraisal. For tools that do this work, see the best mixed-use development analysis software and the underwriting software guide.
FAQ
How do you underwrite a mixed-use property?
Treat it as two or three small properties that share a roof. Split the rent roll, the operating expenses, the reserves and the leasing assumptions by use, give each use its own vacancy, rollover and market rent, then add the NOIs and test the value both with a blended cap rate and by capitalising each use separately.
What cap rate do you use for a mixed-use building?
Either a cap rate from sales of comparable mixed-use buildings, or a blend weighted by each use's share of NOI. Run both. If the sum of the parts capitalised separately is far from the blended figure, find out why before you rely on either.
How do lenders view mixed-use properties?
Many lenders classify the loan by the use that carries most of the income or floor area, and size it on the riskier part of the rent roll. Ground-floor retail vacancy, short commercial leases and a single large commercial tenant are the usual points of discussion.
How should operating expenses be split in a mixed-use building?
By use where the T-12 or the meters allow it, and by floor area where they do not. The commercial leases decide what is recovered from commercial tenants, while residential units usually pay only what their leases name, so the split decides how much of each cost stays with the owner.