Has Coastal Zone Hotel Construction Become the Twilight Zone for Mold & Moisture Control?

By Donald SnellSteve Gleason & Nate Sanders on May 26, 2017


Just months after completing refurbishment on a 300+ room resort, the owner of a luxury coastal vacation resort began to wonder if he had entered into the Twilight Zone when mold and moisture problems suddenly emerged in numerous guestrooms. He was perplexed that this problem was cropping up now despite the fact that he had owned and operated similar properties for many years. Never in all that time had he ever experienced moisture-related issues.

 Why was the problem occurring at this point? What was different?

Resorts, hotels, and vacation ownership properties that have operated for years without significant mold and moisture problems are suddenly becoming plagued with catastrophic and costly moisture-related issues after building renovations are complete.


The cause? Architects, engineers, and contractors who oversee renovations are designing and constructing HVAC and building envelope systems that don’t work with the original building design intent.  The combination of the new systems represents a fundamental change from the way the building was originally designed, constructed, and successfully operated for many years.

The conversion of conventional resort hotels to vacation clubs requires the configuration of new walls and interior build-out that otherwise was not a part of the original resort. Many resorts, especially those found in coastal tropical conditions, do not use wall systems that have framed wall cavities. Walls are historically a plaster or stucco over masonry or concrete.

 Inadvertently, many of these resorts did not know that they had created a fairly forgiving wall system that was protecting them against some of the more common catastrophic types of mold and moisture problems found in the tropics. Why? Because these walls eliminate air flow passages. The elimination of improper air flow through a wall reduces, if not, eliminates the potential for condensation related moisture and mold problems to occur. Building compartmentalization increases with wall systems that are not of frame construction. The masonry and concrete walls increase compartmentalization because individual guest rooms generally have low ability to communicate air from guest room to guest room.

 The second area of concern for these resort to vacation club conversions is the HVAC modifications. Understandably, there are difficulties installing new HVAC systems into an existing building. Existing hotels will have: (1) ceiling heights that will constrain above ceiling space that can receive new ductwork, (2) walls in place that will require penetrating with new ductwork, and (3) even restrictions on the kinds of new MEP services that are required to support new guest room cooling units. The constructability issues can have a significant influence on the designer as the owner pressures the project to remain in budget. Likewise, these constructability issues can influence the contractor’s ability to provide a clean installation because of the increased difficulty of installing new in an existing hotel building.


However, perhaps one of the greatest difficulties to overcome is owner perception that there is a need for the types of new HVAC systems required to achieve the kind of building pressurization to address the new wall system and interior build out that comes with a vacation ownership conversion. After all, as a traditional resort, the owner experienced mostly interior surface mold and moisture problems that were managed by housekeeping. With no wall cavities or interior buildout for air to flow and cause condensation problems, the air would enter the rooms causing mostly visible mold and moisture problems that housekeeping (or engineering) could identify and then clean and manage. This results in a significant inertia from ownership against the design and construction team when recommendations are made for more expensive HVAC systems than was present in the original resort.

 As such, unbelievably, a certain combination of mechanical and building envelope systems continue to be implemented in renovation projects even though the industry has known for years that these designs don’t work, especially in areas where the climate is a historical issue when it comes to the prevention of these kinds of building moisture failures.

 As a result, properties that have performed very well in the past are now unable to prevent mold and moisture problems from occurring puzzling owners, designers, and contractors, alike, making them wonder if they have entered into some sort of tropical twilight zone.