New Development Building Sq Ft Efficiency Benchmarks

[Jon Lee Green]

I am the senior development analyst for a developer that builds all property types from hotels to student housing etc.  I spend a large portion of my time doing high-level new development analysis.  I am trying to establish a benchmark of building sq ft efficiency (leasable or useable sq ft /gross sq ft) plug percentages.  Here are my current ratios:

Office 2-4 Levels : 86% lsf

Office 5 - 40 Levels: 84% lsf

Hotel mid & high rise: 79% lsf

Conference Center:  81% lsf

Apartment Garden: 88% lsf

Apartment Mid-Rise: 86% lsf

Apartment High-Rise: 85% lsf

Student Housing: 83% lsf

Please note these are just plug percentages for new development at a high-level.  This is before speaking to an architect.  I am curious to hear your opinion if a ratio needs to increased or decreased.