Musty smells accumulate in unheated buildings. A two year-study at Bradford Hebrew Congregation found causes and tested minimal-cost remedies. In summary, molds and bacteria grow under humid conditions that result from moisture condensation. Moisture may enter from several sources. When the building is in use and heated, the air becomes largely saturated. When the building is then cooled, the moisture condenses on carpeting and other textiles. Under these damp conditions, molds and bacteria tracked in on shoes are stable on the surface of the carpet and eventually get established in the carpet. Each time the building is heated the molds grow.
The remedy that evolved was twofold. First a mold retardent was sprayed onto affected carpet and textiles. Second, a dehumidifier was used to reduce the moisture content. A study of the electrical operating cost showed that this ranged from $5 to $15 per month depending on operating conditions. This was far less expensive and more effective than heating the 900 square foot sanctuary.
The mold retardent that evolved in this study was based on borate. Borax was neutralized with hydrochloric acid to form a mixture of sodium borate and boric acid. Because of its waxiness, boric acid appeared to be beneficial in promoting adherance of the borate mixture to synthetic carpet. To this was added benzylalkonium chloride in a greater than 1:1000 concentration to attack bacteria. Compatible surfactants were also added to promote wetting. One formula tried was as follows:
1 cup borax into 1/2 gallon of hot water
1/4 cup muriatic acid
2 cups Lysol brand disinfectant (benzylalkonium chloride and surfactant)
Water sufficient water to make one gallon
pH of finished mixture measured 7.0
This mold retardent was sprayed onto the carpet. A total of 2.5 gallons were sprayed over time onto 900 sq. ft.
The dehumidifier used was a Sears Model 251.99701801. This operates in low temperatures and has a 70 qt./hr capacity when operated at normal room temperature. It also has a condensate pump. When the sanctuary is not used, the tube for the condensate is routed to a floor drain in a janitor's closet. Prior to services the dehumidifier is removed and stored. Using a watthour meter, the electrical usage was tracked while operating at 45 to 50 degrees F. For drying, continuous operation resulted in an estimated cost of $15 per month. For maintenance, operation at a 50% R.H. setpoint resulted in an estimated cost of about $10 per month. Operation on an 8-hour per day cycle cost only $5 per month but humidity spiked to 70% during the off period.
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