How to Prevent Mold and Moisture Problems During Hotel Renovation

The time has come to perform that next renovation cycle for your hotel. You have successfully lined up your team of property staff, designers, and contractors. You are pleased with the fresh look proposed by the designers. Work is scheduled around your occupancy rate and the first wave of workers is let loose. You are ready for success… until the unexpected happens.

Hidden moisture and mold damage disrupts your schedule, delays your reopening, requires redesign work, and increases the construction budget with a multitude of change orders. If you had seen this coming, your entire renovation strategy would have been altered from the beginning. But could you have seen it coming?

Here are three examples to help you understand and examine vital signs for potential hidden moisture and mold damage to set you up for a successful renovation.

Tampa Hotel: Overlooked HVAC Issue

Prior to renovations, this Tampa hotel did not have a mold problem behind the vinyl wall covering (VWC). During renovation, the walls were stripped, skimmed with joint compound, and allowed to dry per the manufacturer’s recommendations before new VWC was installed. Mold started to grow behind the new VWC, however, while the renovations were still ongoing. The new VWC had to be torn down and replaced.

The mold problem was caused by an overlooked HVAC issue from a previous renovation, when the outdoor air grilles for the fan-coil units (FCUs) serving the rooms had been painted shut. The FCUs did not have to cool outdoor air loads so they shut down too quickly, before relative humidity in the rooms was reduced. This increased the time the joint compound took to dry, resulting in moisture trapped behind the VWC.

This problem could have been foreseen and prevented by both visual inspections of the HVAC systems and by measuring the vital signs of relative building pressurization and humidity prior to renovation. At the very least, checking the moisture content of the joint compound before applying VWC should have been performed.

D.C. Hotel: Limited Drying of Plaster Walls

This existing Washington, D.C. hotel contained plaster corridor walls with VWC. During renovation, the plaster walls were stripped of the VWC, cleaned, repaired with plaster patching and skim coats, and allowed to dry before the new VWC was installed. Subsequently, the VWC was discolored with pink stains and mold was found on the surfaces behind the stains, but only in specific corridor locations. The new VWC had to be torn down and replaced.

In this case, the problem was caused by overlooking the limited drying potential of the plaster wall and the subsequent lack of drying of the new plaster and VWC paste. Unlike the Tampa hotel, however, the mechanism was not HVAC-driven. The corridor walls were solid plaster (no cavity space). The pink stains and mold occurred in the corridor walls common to the guest room bathrooms, specifically opposite areas of bathtub tile.

The vapor resistance of the large wall tile prevented the drying of the plaster. Damage occurred where moisture in the new plaster was trapped by the tile and the VWC, both acting as vapor retarders. On wall sections where the room side of the wall was not tiled - below the tub line and above the dropped ceiling line - damage did not occur in the corridor. An analysis of the drying potential for the interior walls, as well as checking the moisture content before applying VWC, could have prevented the damage.

Southeast Asia Hotel: Relying Only on Work Orders

Qualitative testing of the exterior wall cavities using a smoke bottle confirmed what should have been obvious in a peer review of the Southeast Asia hotel construction drawings. The building was under negative pressure, drawing hot, humid outdoor air into the exterior wall cavities and causing mold growth.

Qualitative testing of the exterior wall cavities using a smoke bottle confirmed what should have been obvious in a peer review of the Southeast Asia hotel construction drawings. The building was under negative pressure, drawing hot, humid outdoor air into the exterior wall cavities and causing mold growth. This high-rise hotel in Southeast Asia was undergoing a 2,000+-room soft goods renovation when significant mold growth was discovered in certain room walls due to air infiltration and moisture in bathrooms.

Prior to the work, the room renovation team relied on TripAdvisor feedback and on analysis of maintenance work orders to see if there was a systemic mold problem in the rooms.

This assessment, which concluded there was only an “inside-the-room humidity problem,” missed the mold problem. Recovery of costs was pursued from the property insurance carrier and the building’s landlord.

The hotel missed the mold problem by relying only on work orders and guest feedback. Mold growth was hidden in the walls and was thus missed by these assessment methods. Additionally, there was no interaction between the façade engineer and the HVAC engineer. Mold inside the walls could have been discovered before the start of renovation if a detailed mold survey had been done, as well as a professional assessment of the HVAC and building envelope systems and how they interact with each other.

9 Vital Signs to Examine Before Renovation

Just as a doctor reviews a patient’s vital signs before recommending or beginning a procedure, hotel owners/operators and their design/construction team need to check a building’s vital signs before design/rehab to avoid moisture and mold problems. The building failures in the case studies presented above, as well as in many other hotels LBFG has investigated, would have been predictable and preventable if the vital signs had been checked, assessed, and understood through a process of field investigation and focused peer review of the proposed scope of work and impact of new brand standards. Read more about the nine vital signs to monitor to avoid widespread mold problems in your building.