Nantucket, MA

Andrews Building, North Wharf


Originally a single-family house, the two-story, timber-framed building in Nantucket Harbor was in serious disrepair. The owner wanted to preserve and rehabilitate the building on North Wharf and as part of that effort, they needed to raise it above the floodplain as specified by local codes. SGH designed foundation repairs to address deteriorating piles that were insufficient in both stability and height.

Highlights of SGH’s work include the following:

  • Established the required base elevation for the structure
  • Determined design loads on the foundation
  • Designed a foundation system to replace the deteriorated timber piles that incorporated steel helical piles and new pile caps
  • Specified the use of a cathodic protection system to increase the life expectancy of the foundation
  • Developed a construction sequence that included the following:
    • Raising and sliding the building over the water
    • Temporarily supporting the structure on cribbing until the helical piles were installed
    • Resetting the structure at its new, higher elevation
  • Provided construction monitoring services during installation of the helical piles

Project Summary



Completion Date
Repair & Rehabilitation
Andrews Family
Specialized Capabilities
Repair & Strengthening | Temporary Construction | Marine & Civil Works | Geotechnical

Key team members

Rasko Ojdrovic
Rasko Ojdrovic
Senior Principal
Giuliana Zelada-Tumialan
Giuliana Zelada-Tumialan
Associate Principal