RENTERS BEWARE: APARTMENT HVAC CLOSETS CAN BE SOURCES OF MOLD AND DEGRADED IAQ

Furnace on water damaged OSB platform.  The return plenum is located beneath the platform.

Furnace on water damaged OSB platform. The return plenum is located beneath the platform.

A common practice in multi-story apartment and condominium complexes is to house the furnaces in closets that are located on the patio or balcony for each unit. The closets are aligned vertically in each building. Although the orientation is convenient for plumbing access, numerous water damage issues are inherent to this type of HVAC set-up.
Water damage from plugged condensate drain tubes or malfunctioning condensate drain pans is common. Slimy biological growth in PVC tubing and drain pans pan causes overflows. Current or historical overflows from the pans will appear on the sheet metal plenum under the A-coil. Drips and mold growth from malfunctioning units above a closet are commonly apparent as drip stains or growth on the ceiling and walls of the closet.
Water damage caused by freezing and thawing of the AC coils is common in apartment HVAC systems. Filter changes are often left in the hands of uninformed tenants. Plugged filters prevent sufficient air flow to the coil, causing it to freeze. As the coil warms up, the ice thaws, releasing large amounts of water into the return plenum, floor system of the apartment, furnace platform, or furnace closet below the damaged unit.
Another issue associated with stacked HVAC closets is the installation of the furnace on a platform, which is commonly constructed from plywood, drywall, or oriented strand board. When wet, all of these materials support the growth of mold and bacteria, which can produce various toxins. Additionally, the glues and resins in these materials can be liberated when wet.

Ceiling of furnace closet showing water entered from HVAC  closet above.

Ceiling of furnace closet showing water entered from HVAC closet above.

The return plenum in furnace closet systems is located beneath the platform, with the underside of the platform being the top of the plenum, a concrete slab serving as the bottom, and the walls of the platform forming the sides of the plenum. In addition to being difficult to clean, a water damaged common plenum provides both a contaminant source and transport pathway.  Dust mites, insects and their fecal material, garbage, cigarette butts, contaminated chunks of paper, and rodent feces are just a few of the treasures that have been recovered from plenums under furnace platforms.
When damage does occur, the underlying cause of water must be corrected. This involves replacing plugged drain tubing, cleaning drip pans, cleaning coils, and changing filters. For consistency, preventive measures in the form of routine inspections and HVAC maintenance should be the responsibility of the management company or maintenance staff.
Addressing the consequences of the water damage, whether it manifests as biological growth or deteriorated building materials, is imperative to appropriate HVAC hygiene and good indoor air quality. Contaminants on water damaged plywood, OSB, and drywall in the furnace closet and on the furnace platform can cause adverse health effects, whether the growth is active or historical. Once dried, mold and bacteria engage in survival mechanisms that can include toxin production and increased sporulation. When dry, the contaminants are easily liberated into the airstream.  Mold remediation is required when building materials in furnace closets become contaminated. The remediation involves two components (1) removal of the mold or contaminated building material and (2) addressing spores that are released from areas of actual growth. Engineering controls, containment barriers, HEPA filtered air filtration devices, personal protective equipment, HEPA vacuuming, and damp-wiping are all essential for safe and effective remediation in water damaged furnace closets.

Return grille located inside of the apartment behind the furnace platform.  Stains show repeated wetting fo tack strip.

Return grille located inside of the apartment behind the furnace platform. Stains show repeated wetting fo tack strip.

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HOW TO IDENTIFY HIDDEN MOLD, CHEMICALS, AND OTHER IAQ PROBLEMS BEFORE RENTING

Buying or renting an apartment, office or condominium in a multistory building presents challenges beyond the structural and indoor air quality issues that are anticipated when purchasing a single family dwelling. Most prospective home buyers understand the importance of hiring an independent third party home inspector before the purchase of a house. If a buyer has previously experienced illnesses associated with mold, bacteria, and other contaminants in water damaged buildings (WBD’s), a mold assessment is often requested in addition to the home inspection and seller’s disclosure statement. Although the same types of due diligence can be requested for multi-story apartments and condominiums, numerous complexities associated with these multi-family dwellings diminish the likelihood of gathering accurate information.

Identifying issues that could negatively impact indoor air quality can be especially troublesome in rental properties due to policies, practices, and procedures that hinder accountability. Some of these inherent issues include frequent tenant turnover, less stringent disclosure requirements, tenant abuse, poor maintenance, low quality building materials, property management by outside contractors, bylaws of home owners associations, and delayed or unreported damages. Thoroughness and persistence are required prior to signing a rental agreement. Potential health hazards include mold, pesticides, animal and pest allergens, lead, and asbestos, as well as volatile organic compounds from paint cleaning products, carpeting, and building materials.

How to Spot Telltale Signs of Concealed Damage

1. Specific Unit Inspection: Many rental properties can be removed from a list of potentials during an initial walkthrough. Of course this requires that a prospective renter see the actual that he/she would rent. Many property owners have “models” that can be initially viewed, but available rentals cannot be inspected until current tenants move and repairs are completed. A lease should not be signed until the renter (and his/her inspector if desired) approves the unit to be occupied.
2. Uneven Paint: Cracks in drywall seams, different shades of paint, blistered paint, or bumpy textures, especially in the lower corners of

Cracked paint in upper corner of exterior wall signifies water damage and hidden mold

exterior walls, under upper unit bathrooms and kitchens, at the lower corners of windows, and along the lower walls outside of bathtubs and showers, should raise red flags about insufficient water damage repairs, with the likelihood of underlying mold and bacteria contamination.
3. Under Sinks and Vanities: Water stains, visible mold growth, delaminated bases in cabinets, drip stains on walls, and musty type odors are indicative of historical water damage, with the possibility of hidden damage to the flooring below the cabinets, as well as in the wall cavity behind the cabinets. New cabinet bases under sinks can also signify that the base was severely damaged and the floor might remain damaged.
4. Peeling or Uneven Paint in Ceilings above Kitchens or Bathrooms: Uneven paint might represent repair from a toilet overflow or leak, pipe break, insufficient caulking, or other condition that caused top-down water intrusion from an upper unit. Since water from a bathroom can be especially contaminated, extra care should be taken to inspect the ceiling. A flashlight shined at an angle will often reveal the damage. If the drywall appears to have been replaced, documentation should be requested to confirm that joists, subflooring, and other damaged structural members were also appropriately remediated.

Hidden mold behind new baseboard molding

5. New Baseboard Moldings in Bathrooms, Laundry Rooms, and Kitchens: Installation of new vinyl, composite, or wood baseboard moldings is a common practice to cover up the lower edges of walls that were previously affected by a flood, persistent leak, or chronic water damage. When new baseboards are present, check for signs of uneven paint above the baseboards that might indicate that paint was applied over water damaged drywall.
6. Stains under Vinyl Flooring around a Toilet, Tub, or Sink: Chronic water seepage under vinyl flooring will often show up as a slightly darker plume around the source. The stain is usually apparent from the topside, but top surface of the vinyl is not usually altered.
7. Damage to Window Sills or Along the Lower Edges of Doorwalls and Windows: Drywall and wood around doorwalls and windows that have been repeatedly or chronically wet will typically display signs of damage, such as cracks, blistered paint, bumpy or uneven surfaces, and crumbling or weakened drywall. The underlying structures and backsides of drywall are likely to be contaminated if such conditions exist.

Mold on drywall around furnace was caused by leaking condensate drain pan

8. Damage around the Furnace: In most multistory apartments and condominiums, the furnaces are located in closets within the apartment or in a closet area on a balcony or patio. Check for signs of leaks from units above, as well as on and around the furnace, which is often on a wood platform with attached drywall. Damage is frequently caused by leaks from the condensate drain pan, which can get plugged with particulates. Drip stains and rust can often be seen on metal along the outside of a furnace that has not been properly maintained.
9. Rust on Vents and Registers: Excess moisture on vents and registers can be caused by condensation in the indoor environment and/or excess moisture the HVAC system.
10. Chemical Type Odors: New carpeting odors should not be detectable after a few weeks if proper ventilation is provided. If odors are present, find out when the carpeting was installed and request information from the manufacturers’ of the carpet, pad and glue. If no new carpet has been installed, ask about cleaning solutions and type of paint. The MSDS (material safety data sheets and manufacturers’ specification sheets should be made available.

Questions to Ask

  • Request the service and repair logs for the specific unit, as well as the unit above.
  • What is the policy for reporting and repairing water damage? Are procedures in place for handling mold after the source of water is repaired? Who removes mold if found?
  • How are emergency situations reported after offices are closed?
  • Does the property owner’s insurance policy cover personal injuries associated with water damage and mold?
  • Does the property owner or his insurance cover contents that are damaged by water? If so, what is covered, and what are the coverage limits. The answer is likely to be no. Renters should have insurance to cover contents.
  • What types of pesticides are applied? How are tenants notified of pending application? Who does the application? If the building was built prior to 1975, have lead and asbestos surveys been performed. If so, ask to see reports. If not done, and the building is old, the property should not be considered for rental.
  • What is the policy for inspection of the HVAC system and for filter changes?

“Sufficient epidemiological evidence is available from studies conducted in different countries and under different climatic conditions to show that the occupants of damp or mouldy buildings, both houses and public buildings, are at increased risk of respiratory symptoms, respiratory infections and exacerbation of asthma. Some evidence suggests increased risks of allergic rhinitis and asthma. Although few intervention studies are available, their results show that remediation of dampness problems can reduce adverse health outcomes.”

Dampness and Mould, World Health Organization, 2009, section 5.1

http://www.euro.who.int/__data/assets/pdf_file/0017/43325/E92645.pdf

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