The impact of the recent construction boom in South Florida has caused a resurgence of high-rise condos along the coast of Miami and cities north of it like Sunny Isles Beach. This is a tricky region for contractors if they have any intention of reducing their risk of moisture and mold problems during construction. One such tricky area is to know how to control moisture at each stage of construction – from the rough-in construction stage, to the dry-in stage and then to the start-up stage.

During the last boom, circa 2005, there was a rash of moisture and mold problems in this region’s high-rise condo construction that was complicated by the enormity of the buildings and their coastline locations. It became apparent that avoiding these problems meant taking measures at each construction stage to assure proper moisture control. More than mere rainwater control, this requires a determination of how to ventilate for moisture, protect against all kinds of water impact (rain and plumbing related), and protect against humidity control; which is the most difficult to achieve and can result in some of the most devastating mold problems that we have seen.

On example, was a high-rise condo built in the mid-2000s right on the beach. Because of the individual unit layouts it was difficult to get any cross ventilation to the interior spaces. Even though outdoors conditions were adequate to provide acceptable control of interior high humidity build-up the inability of the ventilation source to get to the interior bathroom locations resulted in sustained relative humidity (RH) levels at 70% and above. Resulting in wide spread mold problems in these interior bathroom spaces; Spaces that were very expensive to remediate and build back. Aggravating these conditions were wet processes employed by subcontractors that elevated the levels of moisture in these areas.

Other areas in the condo units had better moisture control and followed closely the cyclical nature of the outdoor south Florida RH. Higher than 70% RH in the early morning hours when temperatures are lower and then lower than 70% RH during the afternoons when temperatures rise (see Figure 1). This does change, of course, during rain events but is otherwise rather consistent during most south Florida days. It is this cycle of RH that keeps buildings during the rough-in and dry-in stages under control for mold problems if and when these conditions can be manifested throughout the building. When there are areas where these conditions cannot be assured these areas can have sustained RH that is high and therefore result in mold growth and damaged building materials.

“The only way to control all of these elements is to know what strategies were needed for every different area of the building – the same strategy cannot be applied across the entire building,” says George DuBose, LBFG President, ”I hope that the institutional knowledge that was gained 10 years ago is still present in today’s projects.”

LBFG has provided problem avoidance and after problem solutions to owners and contractors for buildings under construction by developers like Trump along the South Florida coast; including 50+ story range high-rise condos where moisture and mold problems cost their developers in excess of $15M dollars to resolve. Recently, LBFG and NCARB have developed a new online course for architects, contractors and developers that teach how to avoid these kinds of problems and has extensive expertise in investigating and resolving construction and design deficiencies in the Mid-Atlantic and Southeast states, as well as in Mexico, the Caribbean, Central America, and Southeast Asia.

Figure 1 (Outside): South Florida outdoor RH variances act to control mold growth during the rough-in and dry-in stages.

Figure 1 (Outside): South Florida outdoor RH variances act to control mold growth during the rough-in and dry-in stages.

Figure 2 (Bathroom): Interior spaces like bathrooms do not get acceptable ventilation of outdoor air and thus are kept at RH levels of 70% and above. These conditions resulted in mold growth on bathroom surfaces.

Figure 3 (Bathroom): Example of surface mold found due to poor indoor RH control during the dry-in period of construction.

Figure 3 (Bathroom): Example of surface mold found due to poor indoor RH control during the dry-in period of construction.