Guide

How to Underwrite a Self Storage Facility, Line by Line

Self storage looks like the simplest asset in commercial real estate: metal boxes, no kitchens, no toilets, nobody living there. It is one of the most operationally intense things you can buy, because you re-rent most of the building every year and you compete for every customer on a screen before anyone drives past the gate.

Measure occupancy three ways before you look at the price

Every storage listing leads with an occupancy number, and that number alone tells you almost nothing. Ask for three.

• Unit occupancy. Occupied units divided by total units. The number brokers quote, and the least useful of the three, because a facility full of cheap 5x5 lockers with the large drive-up units sitting empty can post a strong unit occupancy while earning very little.
• Square foot occupancy. Rented square feet divided by rentable square feet. This is the one that tracks revenue potential, because you are selling space, not doors. When square foot occupancy sits well below unit occupancy, the big units are empty, and the big units are where the rent is.
• Economic occupancy. Actual collected rent divided by what the facility would collect if every unit were rented at the current street rate. This is the honest number. Run the comparison on the economic occupancy definition until it is second nature, because the gap between physical and economic occupancy is where the entire story lives.

A facility at 92% unit occupancy and 74% economic occupancy is telling you something specific: it is full of discounts, concessions, promotional first months, delinquent tenants who have not been auctioned, and long-tenured customers paying rates set years ago. Some of that gap is a value-add opportunity you can close with disciplined rate management. Some of it is a market that will not bear the street rates being advertised. Your job during due diligence is to work out which, because paying for the first and inheriting the second is the most common way buyers lose money in this asset class.

Street rate is not in-place rate, and the difference is the deal

Pull the rent roll with a move-in date and a current rate on every single unit, not a summary by unit type. Then build the distribution yourself. You are looking for how far in-place rents sit below advertised street rates, and how that gap correlates with tenure.

Storage runs on a mechanic that almost no other asset class has: existing customer rate increases. Tenants are notified of a rate increase a few months after move-in and periodically after that, and most of them pay it, because moving the contents of a 10x10 unit costs a weekend and a truck and their belongings are already in your building. Competent operators run this program continuously. Tired owner-operators never touch it, and their rent roll fills with tenants who moved in at a promotional rate in 2019 and have paid it ever since.

That is genuine upside, and it is also the easiest thing in storage to overstate. Underwrite it with three constraints. First, rate increases produce move-outs, so model a realistic vacate rate against every increase rather than assuming the whole roll rolls up. Second, check what the street rates actually are today by shopping the competitors yourself online and by phone, because the seller's advertised rate is a marketing number and may be attached to a first month free that quietly erases two months of the gain. Third, confirm what your state and your lease permit in notice terms. If you are pricing in a lift, price in the friction that comes with it.

While you are in the rent roll, separate the income lines. Rent is the core. Tenant insurance or a protection plan is real recurring income at a high margin and can run several percent of revenue, but confirm the program conveys to you and on what split with the provider. Late fees and admin fees are recurring in aggregate, though a facility earning an unusual share of revenue from late fees is describing a collections problem, not a revenue stream. Retail, truck rental, and parking are small and usually stable. Auction proceeds and one-time settlements do not belong in NOI at all. Classify every line in the T-12 on purpose.

The expense load is higher than the brochure suggests

Self storage carries a genuinely low expense ratio compared with most income property, which is exactly why sellers of tired facilities can produce a ratio that looks too good. Rebuild the expense side on what you will pay, not what the seller paid.

• Marketing. The line that surprises buyers coming from other asset classes. Storage customers search, compare, and reserve online, and you pay for that placement every month through search advertising, listing aggregators, and the facility website. An owner-operator with a sign on the highway and no ad spend is not efficient, they are invisible to most of their demand.
• Payroll and management. Either you pay a third-party manager or you pay people. A facility running on a retired owner who lives nearby and answers the phone himself has a payroll line of zero and a real cost you are about to discover.
• Property taxes at reassessment. In many jurisdictions the sale triggers a new assessment, so the bill you inherit is not the one on the seller's statement. Model the reassessed figure, not the historical one.
• Insurance at today's quote. Get a current quote on this facility, in this location, with this construction type. Policies priced in a softer market are not evidence of anything.
• Software, payment processing, and the call center. Management software, merchant fees on card payments, and a call center answering after hours are all real monthly costs, and a small facility running on a spreadsheet has none of them on its P&L and all of them in your budget.
• Repairs, snow removal, and the gate. Doors, latches, gate motors, access control, cameras, and lighting all fail, and in a snow market the plowing bill is not optional.

Then sanity-check the operating expense ratio against comparable facilities of similar size and management structure. A stabilized, professionally managed facility typically runs somewhere in the mid 30s to low 40s as a percentage of effective gross income, higher for a small facility where fixed costs spread across less revenue, and higher again once third-party management is layered on. A listing showing a ratio in the low 20s is not a better business. It is a P&L missing payroll, marketing, or both.

Do the third-party management math explicitly

Most buyers who are not going to sit at the counter themselves will hire a third-party manager, and the fee is rarely just the headline percentage. Price the whole stack before it touches your NOI.

Expect a management fee quoted as a percentage of gross revenue with a monthly minimum that binds on smaller facilities, so the effective rate on a small property is higher than the quoted one. On top of that sit the platform and call center fees, the marketing spend passed through to you, credit card processing, and sometimes a setup or onboarding charge in year one. Add them up as one number and carry it through the model. The difference between a headline fee and the all-in cost of professional management is frequently worth more than the rate increases you were counting on.

The offsetting case is real: a good manager lifts revenue through better rate management, better online placement, and tighter collections. Underwrite the cost as certain and the lift as a plan you have to execute, not the other way around. If you want to see both versions side by side, run the deal once with in-place operations and once with the management stack loaded in, and compare the effective gross income and the resulting value.

Supply is the risk that actually kills storage deals

This is the section that separates storage from the other asset classes on this site, and it is the one most first-time storage buyers skip. Self storage is cheap and fast to build relative to almost anything else, and there is very little stopping a developer from putting a modern climate-controlled facility two miles from yours and buying the search terms you depend on.

Do the work on the trade area before you do the work on the rent roll. Map every competing facility within roughly three miles for an urban site and five for a suburban or rural one, then get each one's current street rates and, where you can, their occupancy. Estimate net rentable square feet per capita in that trade area and compare it against the national average of roughly seven to eight square feet. A market already well above that with more coming is a market where your rate increases will not stick.

Then go find what has not been built yet. Call the municipal planning and zoning office and ask what storage projects are approved, permitted, or in the pipeline. A facility trading at a strong cap rate today can be a lease-up war in eighteen months if two hundred thousand square feet are entitled a mile away, and none of that shows up in a T-12. This one phone call is the highest-value hour in a storage underwrite.

While you are studying the market, look at the unit mix you are buying against what the market rents. Climate-controlled space and large drive-up units command different rates and attract different customers, and a facility built entirely as small non-climate lockers in a market that wants 10x20 drive-up has a mix problem that no rate program fixes.

Reserve per square foot, and look up at the roofs

Storage reserves are best sized per net rentable square foot rather than as a percentage of revenue, because wear tracks the physical building and not this year's rent roll. The items that matter are the roofs, the paving, the doors and latches, the gate and access control system, the security cameras, and the lighting.

Roofs deserve their own attention. A metal roof over rented space is the single largest capital item on most facilities, and a leak does not just cost you a repair, it costs you a customer's damaged property and a claim. Get the age of every roof, walk the interior of the top-floor units looking for staining, and find out whether the gutters and the site drainage actually move water away from the doors. Then price paving honestly: a large asphalt lot at the end of its life is a six-figure item that no seller volunteers.

Turn your NOI into a price, a loan, and a floor

With a defensible net operating income built on real economic occupancy and a full expense load, the rest follows quickly. Build it in the NOI calculator, then divide by the cap rate the market actually trades at to get the price your numbers justify, using the cap rate calculator. Size the debt on the DSCR calculator so you know what a lender will lend against this income rather than against the pro forma. Then find the floor with the break-even occupancy calculator, and read the answer in economic terms: the gap between break-even and your real economic occupancy is your margin of safety, and in a market with new supply coming, that margin is the thing you are actually buying.

If the gap between your normalized numbers and the seller's is large, that is not a problem with your underwriting. That is your negotiation, and it is why you did the work.

Related guides

• The 4 numbers every deal comes down to
• Rebuilding the seller's NOI
• Stress testing a deal

Part of the RVP Underwriter guide library: practical guides to underwriting and buying income property. Browse all guides, or read the complete free guide with a full worked example.