Mold Testing & Inspection in Houston, TX
Preventing Mold Growth - Water Sources from Outside the Home or Building
Mold spores are everywhere. They are in the outside air and they are inside your home or workplace. There are hundreds of thousands of types of mold spores. Mold spores grow best in warm, damp, wet, and humid conditions. Several common mold spores that we typically find in the environment are Cladosporium, Basidiospores, Ascospores, Aspergillus, Penicillium, Alternaria, Myxomycetes, Smuts, Stachybotrys, and Chaetomium.
At the present time, there are no governmental or Occupational Safety and Health Administration (OSHA) permissible exposure limits (PELs) or American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) established for mold growth. Due to the absence of these exposure limits, it is common industry practice, as supported by ACGIH, the American Industrial Hygiene Association (AIHA), and the US Environmental Protection Agency (EPA), to compare inside air quality sampling for mold to outside air quality sampling for mold. Generally speaking, the inside air quality for mold should be quantitatively lower than, but qualitatively similar (genus or species) to that of the outside air quality. Whenever we open a door or window in our homes, we let fresh air into the home from the outside. Mold spores come into the home when this occurs. The reasons we typically do not have high mold spores within our homes is because we are typically dry inside, we control relative humidity levels, we filter our air (quite often with a high efficiency particulate arresting filter or HEPA filter), we clean (wet mop and wipe down counters with an all-purpose cleaner) and we vacuum our home or office area (quite often with a vacuum cleaner that has a HEPA filter). Generally speaking, dry, clean homes have less mold spores than homes that are dirty, have water issues and homes that are not maintained.
The key with dealing with mold exposure in your home or workplace is to control moisture. By controlling moisture, you can control mold growth. Without a water source, mold growth cannot occur. What does controlling moisture really mean? Let's start off by looking at the outside of a residence or a building. These are some of the inspection items that we look at when completing a whole house inspection. The outside grading around a home or building is very important. When rain or flooding occurs, we want to have the water move away from the building vs. towards the building. Sloping of the landscape is critical in achieving the goal of moving water away from the building. Gutters are used to capture and move rain that is dropping on the roof away from the home or building. This is a key control item. Homes that do not have gutters let the rain drop off the edge of the roof and when it hits the ground quite often splashes back onto the exterior siding. There may even be a discoloration at the bottom area of the home approximately one to two feet from the ground which is very evident. This area of discoloration has been constantly wet during rains and has the potential to even saturate the exterior wall cavity. Gutters can solve this potential issue. Additionally, drains are often used to also collect water from low lying areas and move water away from the building.
Flower beds and planters up against a home is not a good idea. When these items are built around a home, moisture is an issue. You do not want the dirt to be piled up against the home. The dirt and plants hold moisture. Constant moisture up against a home will at some time saturate the construction materials. Once that moisture comes into contact with an organic food source such as wood or sheetrock wall, mold growth can occur.
Sprinkler systems that spray water up against a home or building are not a good idea. Saturating the exterior construction materials on a home constantly has the potential to cause mold growth within the interior wall cavity areas. Sprinkler systems should spray away from the building.
Brick homes have weep holes typically at the bottom of the brick veneer wall area at the concrete slab but can also be found above windows and garage doors. The function of a weep hole is to let potential water that has penetrated the wall to escape or drain from inside the wall cavity to the outside. The weep holes are designed to reduce water intrusion into the home. Builders typically install the holes approximately 1 foot to 1½ feet apart. It is extremely important that you do not cover up weep holes with dirt/concrete/caulking.
Pier and beam homes need to keep water from getting under the home. When water gets under the home, there is constant moisture and high relative humidity which may potentially cause mold growth within the crawl space. The mold growth within the crawl space may have the potential to influence the interior air quality of the home. The crawl space must have plenty of air flow underneath the home to keep it dry. Flower beds, vegetation, storage of items may end up blocking the vents that allow air flow under the home. Consideration must be given to moving these items so air flow can get to the crawlspace.
Keeping the exterior of the home well maintained, will keep the interior part of the home dry. Roof leaks, rotted exterior boards, broken windows, rotted window sills, poor caulking all need to be repaired to keep the interior dry. Pipe penetrations such as gas, water, and AC System Freon lines need to be sealed at the exterior wall. Flashing around chimney areas need to be check periodically. Pipe penetrations for sanitary vent piping systems and heater box vent pipes in the roof need to be periodically checked for degradation and caulking purposes. These are some areas to consider on the outside of the home. Maintenance is the key.
If you have further questions or would like to set up an inspection or testing, please contact Robert J Reda & Associates LLC.
Robert J Reda CIH, CSP, MAC
Robert J Reda & Associates LLC
Providing professional consulting services in Safety, Industrial Hygiene, and Environmental
Texas Department of Health Services Licensed Mold Assessment Consultant