Office to residential conversion is pitched as the obvious fix for empty towers, and for most buildings the math never clears. The story is clean: cities need housing, offices sit vacant, so turn one into the other. The underwriting is not clean. Two hard constraints defeat most candidates before design begins. The building's floor plate is usually too deep to bring light and air to code-required bedrooms, and the seller's price is still too high relative to what a residential asset will pay for the finished space. Gensler, which has assessed office stock across more than 40 cities, found only about 30% of buildings it studied are suitable candidates. The other 70% fail on geometry the developer cannot cheaply change.
Key Takeaways
Gensler found only about 30% of the office buildings it assessed across 40-plus cities are suitable conversion candidates, so most towers fail before design starts.
Floor plate geometry is the binding physical constraint: deep-plate buildings cannot bring natural light to code-required residential rooms without expensive structural coring, per Gensler.
Goldman Sachs research found office acquisition prices would need to fall nearly 50% in the most remote-work-affected metros for conversion to pencil, so basis, not vision, is the gate.
Goldman Sachs projected the office-to-multifamily conversion rate rising only to roughly 0.6% in 2026, confirming that conversion is a niche outcome, not a market-wide fix.
Conversion can run 30% to 40% cheaper and faster than ground-up on the right building, per Urban Land Institute, but only the minority that clears both the geometry and the basis test.
Why Does Floor Plate Geometry Kill Most Conversions?
Floor plate geometry kills most conversions because residential space needs light and air that deep office buildings cannot deliver. Housing codes require windows in bedrooms and living spaces, so every habitable room must sit near an exterior wall. Office towers built for open floors are often too deep from window to core, leaving a dark, unusable center that no apartment layout can absorb.
This is why Gensler weights floor plate and building form most heavily in its conversion assessment, and why it found only about 30% of studied buildings suitable. A narrow-plate building from before 1990, with operable windows and a central core, converts well because light reaches the interior. A deep-plate 1980s or 2000s tower does not, and fixing it means coring a light well through the structure, an intervention Gensler describes as often financially prohibitive. As one conversion architect framed it: "You cannot renovate your way out of a floor plate. The geometry either works for housing or it does not." The developer inherits the building's shape and cannot cheaply change it, which is why so many candidates fail on the first screen. The exercise resembles a highest and best use analysis where the physical form, not the market, sets the ceiling.
Why Is the Acquisition Basis Usually Too High?
The acquisition basis is usually too high because sellers still price offices above what a residential outcome can support. A conversion pencils only when the purchase price plus conversion cost lands below the finished residential value. Office owners, often holding at legacy bases or resisting write-downs, ask more than that math allows, so the deal dies on entry price.
Goldman Sachs research quantified the gap: office acquisition prices would need to fall nearly 50% in the metros most affected by remote work for conversion to be financially feasible. That is not a rounding adjustment. It is a repricing most current owners will not accept until forced. This is why conversion volume stays small even as vacancy stays high. Goldman Sachs projected the office-to-multifamily conversion rate rising only to roughly 0.6% in 2026, a niche outcome. The buildings that convert tend to be ones acquired at a distressed basis, often after a loan default or a deeply discounted sale, not ones bought at the owner's asking price. Basis, not architectural vision, is the gate. The going-in cap rate on the office as-is has to imply a price low enough that residential value covers it plus the rebuild.
Feasibility test | What it requires | Why most buildings fail |
Floor plate | Shallow depth so light reaches interior rooms | Deep-plate towers leave unusable dark cores |
Building form and windows | Operable or replaceable windows, workable core | Sealed curtain walls and large cores resist layout |
Acquisition basis | Price low enough that residential value covers it | Sellers hold above conversion-feasible prices |
Conversion cost | Plumbing, egress, envelope within budget | Systems must be added to every new unit |
Regulatory path | Zoning, code relief, timeline | Entitlement and code delays erode the return |
How Do the Numbers Pencil When a Conversion Works?
When conversions do work, they win on cost and speed against ground-up, but only after clearing the geometry and basis tests. The Urban Land Institute notes conversions can run 30% to 40% cheaper and faster than new construction on a suitable building, because the structure and envelope already exist. That saving is real, and it is why the right building converts profitably.
A simplified worked example shows the sensitivity. Take a 200,000-square-foot office. Suppose finished residential value supports $400 per square foot, or $80 million. Suppose conversion cost, on a building with good bones, runs $250 per square foot, or $50 million. For the deal to clear a developer margin, the acquisition plus soft costs must land below roughly $30 million, or $150 per square foot on the office. If the seller wants $220 per square foot, $44 million, total cost reaches $94 million against $80 million of value, and the deal is underwater by $14 million before any overrun. The gap is the seller's price, exactly the roughly 50% haircut Goldman Sachs describes. Change the building to a deep-plate tower and conversion cost climbs past $350 per square foot for structural coring, and even a cheap acquisition cannot save it. The math works only when a shallow-plate building meets a distressed basis. Miss either input and the pro forma goes negative, which is why the outcome is rare rather than routine.
Frequently Asked Questions
What percentage of office buildings can be converted to residential? Gensler, which assessed office stock across more than 40 cities, found only about 30% of the buildings it studied are suitable conversion candidates. The other 70% fail primarily on floor plate geometry that cannot bring natural light to code-required residential rooms without prohibitively expensive structural work.
Why do office to residential conversions usually not pencil? Conversions usually fail because the acquisition basis is too high. Goldman Sachs research found office prices would need to fall nearly 50% in the most remote-work-affected metros for conversion to be feasible, so most deals die on entry price before floor plate and code issues are even reached.
Are office conversions cheaper than building new housing? On a suitable building, yes. The Urban Land Institute notes conversions can run 30% to 40% cheaper and faster than ground-up construction because the structure and envelope already exist. That advantage applies only to the minority of buildings that clear both the floor plate and acquisition-basis tests.
Conclusion
Office to residential conversion is a real strategy for a narrow set of buildings and a fantasy for the rest. The constraint is not ambition or policy. It is geometry and price. A building's floor plate decides whether housing can fit at all, and only about 30% of assessed office stock passes that test. The seller's basis decides whether the numbers clear, and prices generally need to fall nearly half before they do.
The operator who treats every empty tower as a conversion candidate will burn diligence budget on buildings that were never feasible. The discipline is to screen for shallow plates and distressed bases first, and to walk from anything that fails either test. Conversion is not the market-wide answer to vacant office. It is a precise trade that works when a convertible building meets a motivated seller, and almost never otherwise. The math is not pessimistic. It is arithmetic, and the arithmetic rarely clears.