The single biggest gap between projected and actual returns in commercial real estate comes from underestimating two things: capital expenditures and tenant turnover costs. Roofs last 20 years, HVAC systems 15, parking lots 10 — and tenants leave. Every one of these events carries a cost that most proformas either undercount or ignore entirely. If you want your actual returns to match your underwriting, you need to budget for them honestly and fund reserves from day one.
Capital Expenditure Benchmarks by Property Type
Industry benchmarks express annual capex as a percentage of property value. Class A office runs 0.75–1.0% (well-maintained with modern systems), Class B office 1.0–1.25% (moderate deferred maintenance typical), and Class C office 1.25–1.50%. Multi-tenant retail falls in the 0.75–1.0% range. Single-tenant NNN is the exception at just 0.0–0.25%, since the tenant bears most capital costs under the lease. Industrial properties average 0.5–0.75% due to simpler building systems, and apartments run 1.0–1.25% because unit turnover drives regular renovation cycles.
But percentages only tell part of the story. For a $5 million Class B office, the benchmark suggests $55,000 annually. Check that against the actual replacement schedule: a roof replacement at $150,000 amortized over its 20-year life costs $7,500 per year; HVAC at $80,000 over 15 years costs $5,333; parking lot seal-coating at $30,000 every 5 years is $6,000; exterior painting at $60,000 every 7 years is $8,571; full parking repaving at $100,000 every 10 years is $10,000; and a lobby refresh at $50,000 every 8 years is $6,250. Add those up and you get $43,654 in annualized replacement costs — reasonably close to the benchmark, which gives you confidence the budget is grounded in reality rather than a guess.
The Hidden Cost: Tenant Turnover
Tenant turnover is where most proformas fall apart. When a tenant leaves, you don't just lose rent — you incur a cascade of costs that can easily exceed a full year's rent for that space. Leasing commissions typically run 4–6% of the total lease value. For a tenant paying $20,000 per year on a 5-year lease, that's $4,000–6,000 to your broker. Tenant improvement allowances — the buildout costs you contribute to attract a replacement tenant — range from $10 to $30 per square foot. A 3,000-square-foot space could require $30,000–90,000 in TI. Basic turnover costs (painting, cleaning, minor repairs) add $2–5 per square foot. And then there's vacancy loss: 2–4 months of downtime at $20,000 annual rent means $3,300–6,700 in lost income.
For a multi-tenant property with five spaces and 20% annual turnover, one space turns per year. The all-in cost: roughly $5,000 in commissions, $40,000 in tenant improvements, $5,000 in turnover prep, and $5,000 in vacancy loss — about $55,000 annually, or 5.5% of NOI on a $1 million rent property. That's a material drag on returns that most offering memorandums conveniently omit.
The Real Number: Most proformas model 0–2% for capex and ignore turnover entirely. Actual properties spend 2–4% on capex plus 3–6% on turnover, totaling 5–10% of NOI. This is the single largest reason projected returns exceed actual returns, and it's entirely preventable with honest budgeting.
How to Structure Your Reserves
Lenders typically require segregated reserve accounts funded at closing: 6–12 months of debt service, 3–6 months of operating expenses, and 0.5–1.0% of purchase price earmarked for capital. These are mandatory, but they're also the minimum — not the target. Your monthly reserve contributions should cover both annualized capex and anticipated turnover costs. For that $5 million office with $55,000 in annual capex needs and $50,000 in annual turnover costs, that's $8,750 per month set aside. On $350,000 of annual NOI, you're reserving about 2.5% of income — a reasonable drag that keeps you solvent when the roof needs replacing or your second-largest tenant doesn't renew.
Over a five-year hold, consistent monthly contributions build $525,000 in reserves — enough to handle planned replacements and absorb one or two unexpected capital events without scrambling for emergency financing or deferring maintenance. Deferred maintenance is never free; it just converts a manageable annual cost into a larger, less predictable future liability that depresses property value at exactly the time you're trying to sell or refinance.
Frequently Asked Questions
Should I budget more for capex in the first few years after acquisition?
Yes. Budget 1.5 times the benchmark for the first three years to account for deferred maintenance that surfaces post-acquisition, then drop to the standard benchmark. Even with thorough due diligence, newly acquired properties almost always reveal repair needs that weren't apparent during inspection — it's the nature of complex physical assets.
What happens if I don't fund reserves?
Cash flow shortfalls when major systems need replacement. Lenders restrict distributions. You may need emergency refinancing or additional debt at unfavorable terms. Deferred maintenance compounds — a $30,000 roof repair becomes a $150,000 roof replacement. The property deteriorates visibly, tenant quality declines, and valuations can drop 10–20%. Underfunded reserves are the single most common path from a good investment to a bad one.
Are reserve contributions tax-deductible?
Leasing commissions and turnover costs are generally deductible as operating expenses. Tenant improvement allowances may need to be capitalized and depreciated over the lease term. Capital expenditures like roof replacements are typically depreciated over their useful life rather than expensed immediately. The treatment varies by item and your specific tax situation, so consult your CPA for the right approach.