Market Outlook

Sellen’s team has hands-on experience with the 2018 International Building Code (IBC) changes and the cost impacts that must be considered by owners, architects and builders to ensure successful outcomes. The code revisions place a strong emphasis on creating more energy-efficient buildings. While we will only focus on a few topics here, the revisions are widespread and directly impact multiple project types.

We have honed in on the scopes that have the most significant impact on commercial structures. Our key findings are below.

Architectural

 
  • Building envelopes must feature a lower window-to-wall ratio or a higher performing window system.
  • Window system improvements must lower thermal bridging, increase thermal performance and pass envelope pressure testing.
  • Elevator pressurization requirements are more restrictive and require a number of additional pressurization tests in several new elevator operational modes.
  • Mass timber adoption has resulted in three new construction types, allowing for additional flexibility for mass timber projects.
Mechanical

 
  • The new code requires a dedicated outside system and increases the minimum allowed for heating and cooling efficiency, which overwhelmingly require hydronic systems to meet requirements.
  • Mechanical ventilation requirements for multi-family residential units have been increased.
  • Special inspection requirements for smoke control systems and fire sprinkler systems are now in place.
  • Fire marshals can now require a fire watch during construction for projects over 40 feet tall.
Electrical

 

New code includes changes to the GCFI requirements; added metering; more lighting control in open office areas; electric vehicle charging station requirements; and photovoltaic panels for renewable energy strategies.

Structural

 

Seismic demands are increasing across the board, but the uptick will vary greatly depending on the following:

  • Performance-Based Design or Code Prescriptive
    Large projects using a performance-based design (PBD) method will see a slight uptick in the seismic demands. Projects using a code-prescriptive approach will see more significant increases.Code prescriptive buildings are based on most recent edition of the ASCE 7 Reference Code, which dictates design loads on buildings. The upcoming version of the ASCE 7 Code (2016) is catching up on all the latest data on seismic hazards since the last edition was published.
  • Soil Type
    Buildings on poor soils will see higher increases than those on better soils. This change was driven by research indicating soil amplification of seismic demands through poor soils has historically been under-predicted.
  • Building Dynamics
    When situated on poor soils, buildings with sway periods between one and three seconds will see higher increases than those outside this range. For example, in buildings that are between 5 and 20 stories tall, the height of the structure tends to feature dynamics that align with the soil’s response, further amplifying seismic requirements. A study of the 1985 Mexico City earthquake showed that most of the buildings that collapsed from the magnitude-8.0 event were within this height range.

We anticipate buildings located on good soils will see cost increases of around 10% to 15% for lateral systems. Projects on poor soils will see an increase of 50% or more on the lateral system.

Mass Timber Structures

 

The 2018 code revisions advanced mass timber construction for properties up to 270 feet tall and provided a variety of clarifications for smaller mass timber buildings. We have seen a marked uptick in mass timber structures in the region and expect the trend to continue.

 

Click here to read about the third and final topic: Sellen’s integrated design and construction initiative. 

Integrated Design and Construction