Beyond the Build

Construction Trends

Vertical Expansion in an Existing Building

Sometimes the only place to go is up.

Next year, we’re starting a redevelopment for which we and our customer considered several expansion options. One from the early design phase was going vertical above the roof.

On the urban stage, we’re seeing more landlords request that their building be designed with potential vertical growth in mind. This means higher tolerances than necessary for the existing space, and easy access to the buildings systems, including mechanical, electrical and plumbing, if vertical expansion is an option. But what if one is dealing with an older building, perhaps one that was built before some of the current building codes were adopted?

The first step is to have the existing building evaluated for its capability to expand vertically, analyzing codes and the structure. Foundations, columns and lateral/seismic loads are all part of it. If the structure and other codes requirements can be altered to meet the criteria for expansion, a few other top of mind considerations:

  • Watertightness during construction is the main concern. Keep the existing roof systems functioning best you can and even more important in a live environment
  • Locate the existing columns and uncover them a few at a time. Ensure they are prepped for expansion. Build temporary boxes over column locations and waterproof them. These can be removed when it’s time to go vertical.
  • Identify mechanical/electrical service chases and align new addition design to accommodate current chase locations.
  • If the existing mechanical/electrical room will not physically accommodate new addition requirements for equipment, consider a mezzanine level to house additional equipment.
  • Don’t forget main service upgrades to feed the additional floor requirements.

As Mark Twain said, they aren’t making any more land. If you can’t increase the footprint of an existing structure, go vertical, relocate or demolish and start over.

Merrill Stewart Jr.

Merrill Stewart is Founder and President of the Stewart Perry Company, a commercial building contractor based in Birmingham.