Finding an office building that didn’t exist.

The portfolio spanned many measurement standards depending on the asset and the lease language: BOMA 2024, BOMA 2017, BOMA 2010, BOMA 1996, REBNY, and BOMA Gross Areas on a handful of properties. As contributors to the BOMA standard language and interpretation, Stevenson Systems went into the measurements with certainty.

Every Stevenson Systems measurement is built on industry-defining workflows. We make sure we understand the property completely before any calculations are made. An SSI Measurement Specialist walks the property, scans it, and confirms what the space contains. That gives a highly detailed picture of every asset and lets the measurement reach the highest possible accuracy.

After six months of field verification and production processing, the RSF potential began to surface. 43 of the 46 measured properties carried additional rentable area, some in small pockets and others in large portions. In total, the uncovered rentable area came to 440,784 SF.

Across the owner’s major markets, the distribution of the found area was very promising.

Those are prime Class A leasing markets, which is where found area prices highest, so it can be capitalized effectively and consistently.

That’s not all, though. Look at the found area as a whole and something big shows up. The average property in this portfolio runs a little over 280,000 square feet. The uncovered rentable square footage is more than one and a half times bigger than a typical building in this portfolio.

This is how the building that didn’t exist was uncovered.

Found square footage matters once a lease event or an acquisition lets it price. For this analysis, we valued the found area at Q2 2026 asking rents in the submarkets where it was identified, then discounted to net effective to reflect the concessions landlords are offering right now.

Blended across the portfolio, asking rents on that space come to $44.20 per square foot. At full capture across the entire lease cycle, that’s $15.6 million a year in net effective rent, all from a building with no construction, logistics or architectural cost behind it. It’s the closest you can get to money out of thin air.

RSF capture follows the lease cycle, so the question is how soon this space can be annualized.

Factor in the cost of remeasurement, and the math is still very favorable.

For this portfolio slice, the measurement engagement cost roughly $1,000,000. Daunting on paper, but the cost disappears fast. Even with just the vacant-space tier above, the found area returns $2.85 million a year, with no lease negotiation and no waiting on rollover. That pays back the full investment in about 4 months.

Capitalized at a 7.4% office cap rate, that same tier carries $38.5 million in asset value. Finding this additional building cost only 2.6% of the value it identified, and that number only goes up through renewals and, eventually, a full cycle.

RSF often develops gaps over a building’s lifetime, as things change and transition.

1. 01

   BOMA has revised its office measurement standard repeatedly since 1915. Every revision changes how common areas, vertical penetrations and shared amenities count toward rentable area. A building measured correctly a decade ago can measure differently today.

2. 02

   The space inside changes too. Corridors get reconfigured, amenity space gets added, and a mechanical room takes on a new use. Each change shifts the rentable area, and the record only catches up when someone remeasures.

3. 03

   Acquisitions carry old numbers forward, too. Square footage transfers with the asset, and remeasurement often tests the validity of that number.

None of this is easy to detect, because none of it appears on a rent roll. It surfaces when a team like Stevenson Systems walks every building and remeasures to the highest possible accuracy.