SEMCO Solution: Marriot’s Frenchman’s Cove

A world-class resort in St. Thomas was need of a long-lasting rooftop deck surface durable enough to sustain unpredictable climate swings—SEMCO delivered.


St. Thomas, a luscious tropical retreat located in the beautiful U.S. Virgin Islands, is known for many things, including its diverse weather conditions, ranging from unpredictable rainfall to furious hurricanes. These disparate, and often volatile weather conditions had wreaked havoc on the rooftop event deck of the Frenchman’s Reef and Morning Star Marriott Beach Resort.

Marriots Frenchmans Cove - water damage
Case Study: Marriot’s Frenchman’s CoveSevere water damage to the rooms bellow the deck after the the rain.
Marriots Frenchmans Cove - existing conditions
Case Study: Marriot’s Frenchman’s CoveExisting concrete substrate below tile layer was damaged by water, causing structural weakness.
Marriots Frenchmans Cove - tiles removed
Case Study: Marriot’s Frenchman’s CoveTiles were removed from the deck the in sections.

Past waterproofing efforts had proved ineffective, so the resort approached SEMCO in April 2015 with the challenge of creating a deck surface durable enough to sustain the diverse climate conditions 365 days a year, while also providing a beautiful, seamless aesthetic appropriate for a world-class resort.

Exploring Alternatives

The resort had attempted to install a new deck using conventional methods, which proved ineffective. Rather than repeating the process of reinstalling and waterproofing the event deck, the property was looking for a more permanent, long-lasting solution.


SEMCO surface engineers evaluated the deck’s condition and determined that the roof tiles were hollow and largely delaminated, and the floor drains faulty. A core sample showed multiple layers of incompatible waterproofing materials. Also, water was seeping into the lower 5th and 4th floor premium suites, raising concerns of corrosion within the steel structure. These challenges were compounded by the following factors:

  • The resort’s remote location
  • Unpredictable weather
  • Short, three-month time constraint for completion
  • Work hour restrictions
  • Strict labor laws in St. Thomas
  • Distance for material holding area
  • Limited property access


SEMCO’s innovative surface engineering team, which thrives on making the necessary adjustments for all their projects, drew up a plan that would effectively:

  • Remove the deck in sections
  • Clean and install a waterproofing cover
  • Build a 1.35% slope to move water from 6” to 1/4” across the 32’ deck
  • Mount a new gutter system to the outside of the building
  • Install a beautiful, durable finish
Marriots Frenchmans Cove
Case Study: Marriot’s Frenchman’s CoveSEMCO technicians applying X-Bond Brown Coat over existing concrete substrate.


SEMCO’s expertise in coordinating advanced architectural design, executing customized project management, and delivering top-notch product solutions all came together on this unique project. In the end, SEMCO delivered a viable solution for the resort’s rooftop deck on schedule, in half the time it would have taken any other competitor.

Marriots Frenchmans Cove - X-Bond Seamless Stone
Case Study: Marriot’s Frenchman’s CoveX-Bond Seamless Stone surface stopped water from penetrating the deck structure.
Marriots Frenchmans Cove - new X-Bond Seamless Stone surface
Case Study: Marriot’s Frenchman’s CoveWaterproof X-Bond Seamless Stone surface.
Marriots Frenchmans Cove
Case Study: Marriot’s Frenchman’s CoveSEMCO X-Bond Seamless Stone was used to resurface exterior walls.

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Project Information

  • Preparation: SEMCO Nu-Lift Cleaner and Stone Soap
  • Floors and walls: SEMCO ADA Safety Floor and Natural Shield Sealer
  • Project size: 8,200 sq ft
  • Project year: 2016

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