Mold spores are tiny microscopic organisms that can only be seen under a microscope. Mold spores can become airborne just by walking near an affected area. Aspergillus and pennicillium mold can stay airborne for up to eight hours after one small air movement. Proper containment is a critical step; if not done correctly by a certified mold removal technician, the mold spores can spread and expand the required work. 

Imagine what happens to air quality during mold remediation which involves multiple technicians, equipment, demolition, etc. You guessed it! It gets pretty bad and all that mold can travel through the air columns to previously unaffected areas if proper engineering controls are not put in place. This is one area where corners are frequently cut in the industry.

First of all, poly sheeting (typically 6 mil) should be installed in the work area to isolate affected areas from unaffected areas. These barriers should be well sealed and may have a zipper door or flap in place. Any holes, gaps, open soils, salvageable insulation, contents, seams, duct work, vents, or openings should also be sealed off to isolate the work area. Once this has been achieved it is imperative to install a negative air system to place the work space under negative pressure relative to the unaffected area. This prevents fugitive mold spores from escaping to other areas of the building. If mold spores are spread, it is the contractors liability and they are responsible for the damages. Negative pressure should be maintained between -4 to -6 pascals (measured by a machine called a monometer) to prevent creating too much vacuum. Too much vacuum can draw particulates in to your containment, draw in gases, and can put excessive pressure on your poly sheeting which could cause collapse. It is crucial to monitor pressure differentials especially while entering and exiting your work space. Any time you enter or exit your work area, you open the sealed off space and air rushes in. Pressure must always stay negative (vacuum) or you could spread contaminants upon opening your barrier.

Air scrubbers must also be utilized to condition the air during the mold remediation work. Air scrubbers are large HEPA (high efficiency particulate air) filtered machines that clean the air at a given rate per hour. Depending on the project the goal should be to achieve an air exchange rate of at least 3-10 air changes per hour. This is calculated by taking the square footage of the area and the ceiling height to determine the cubic footage. Once this number is calculated air scrubbers should be employed accordingly to clean every cubic foot of air x number of times per hour. This keeps the work area as clean as possible throughout the remediation process. Air scrubber filters should be cleaned or changed based on project requirements.  Many projects will also require special low grain dehumidifiers, supplemental heat, supplied air machines, make up air filters, etc.

Every mold remediation project is unique and will have slightly different requirements; however, this can serve as an overview you can use to better understand the remediation process. Proper containment is a critical step that if not done right can simply spread the problem and expand the required work.  In our next article we will discuss the actual mold removal process which can involve a number of different approaches.

Mold in our home and work environment has become an increasing hazard as our buildings get older and tighter. First of all, it is important to understand that mold spores are found everywhere and you will never get rid of mold spores completely. Mold is an essential micro-organism that is needed for life to flourish. Mold eats and degrades dead organic matter in the outdoor environment and is critical to the decomposition process. That being said, "mold growth" is never acceptable in a living or work space. Mold can become a problem whenever moisture levels or humidity levels become high enough to support development which can be as low as 16% moisture content or 60% humidity depending on the type of mold.

If you have or suspect mold in your work or living space, the first step is to determine a proper work scope.  A mold inspector or remediation company in Maine can inspect the damage to determine the best course of action however it is typically best to consult a 3rd party industrial hygienist (IH) for testing and assessment of potential health hazards. It is NEVER acceptable to have the company proposing remediation (mold removal) to also conduct the testing services. This is a serious conflict of interest and is illegal in many states and frowned upon in the rest. An industrial hygienist has at least a Bachelor's degree and is certified by the board of industrial hygiene to conduct proper testing, provide a full work scope and to identify safety and health hazards. The "IH" works for you the property owner and oversees the remediation work to ensure a proper outcome. Many home inspectors and mold removal contractors try to take over this task without the proper credentials. A home inspector or mold contractor is qualified to identify mold and to identify causes, but once the inspection takes place it should be turned over to an IH for proper handling. An IH can also certify that based on the results of post mold remediation testing that no health risks are anticipated; an inspector or remediator can not determine this.

Once a mold problem has been identified and a work plan has been established, the remediation firm must then follow the steps outlined by the industrial hygienist. These steps can vary depending on the type of damages however the eight step process that should be followed are:

1. Proper identification & work scope;
2. containment / engineering controls;
   
3. controlled demolition & or abrasive removal;
4. pre-cleaning;
5. secondary hygienic cleaning;
6. treating /sealcoating salvageable framing if applicable;
7. final inspection of work area; and
8. 3rd party post testing to verify cleaning efficacy.

These steps will work every time if followed properly. In the next articles we will discuss these eight steps in detail and break down the process of remediation. We will also discuss short cuts that are often taken by remediation firms that you should look out for. Health and safety hazards are plentiful when mold problems are confirmed; be sure that you are getting your project handled correctly!

Crawl Space Venting Often Causes Condensation, Mold Growth, Poor Indoor Air Quality and Higher Energy Bills.

Venting on a Hot Summer Day

When we say relative humidity we mean how full of water the air is relative to the maximum amount of water it can hold at a certain temperature. Think of what happens when you take a soda can out of a refrigerator on a warm summer day. Water droplets form on the exterior of the can and the can "sweats."  This is because you have reached dew point on the cans surface.

When you allow warm moist air into a cool damp or moderately damp crawlspace through vents you are overwhelming the crawlspace air with excess water vapor. You will eventually reach dew which causes water droplets to form on pipes, concrete, framing, wiring, etc.  The eventual result will usually mean severe water damage, mold damage and dangerous mold growth in the crawlspace.

The source of the cooling air in the crawl space is the earth, and the source of the warm air coming in is the crawl space vents or doors, so the surfaces in your crawl space are always colder than the air in a crawl space.

Now, on a summer day, there is condensation and the crawl space walls get wet, the dirt surface of the floor gets wet, the air ducts get wet - especially if we have the air conditioning on because the ducts are cold – and the cold water pipes get wet. These surfaces are the coldest. Our floor joists, girders, sill plates and insulation all get wet as well.  And as the insulation gets wet, it often develops mold on the paper backing and eventually falls down to the crawl space floor.

High humidity in a crawl space causes any porous materials to soak up water vapor from the air. There is a direct link between the relative humidity and wood moisture content. Wood in a damp environment will become damp too – and damp wood will also support mold growth.

All of these wet surfaces in a crawl space will eventually have to dry too at some point. So say you have the hot summer days that cause condensation in the crawl space, then you have four or five days that are cooler and mild. Is the problem over? Not a chance. After the hot days we are left with an area with multiple wet saturated surfaces. They dry into the crawl space air over the next weeks and months, and meanwhile, mold and wood destroying fungi are taking over your house.

Venting on a Spring or Fall Day

If a day is 72 degrees outside and it is humid out such as 80%, then allowing this air into a crawl space will also cause condensation. 80% relative humidity (RH) air cooled ten degrees increases its RH by 22%, which added to the 80% RH is over 100%.  This means condensation in the crawl space. Is this an extremely hot day? Absolutely not, it's a typical room-temperature day, yet we are left with a wet crawl space. Any time humidity levels exceed 60% there is a significant risk of mold activity occurring.

Venting on a Cool or Winter Day

If the RH of air goes up when we cool it, it goes down when we heat it. If a crawl space is vented in the winter and 35 degree air is mixed with 60% RH and air is warmed in a 62 degree crawl space, the RH goes to 3%. With this dry air we can begin to dry our crawl space. The dry cold air mixes with the crawl space air and cools the crawl space.  As a result we have water evaporating from the earth into the crawl space air so we never actually achieve 3% RH in our crawl space, but materials dry out and there is no condensation. The new problem now is cold floors, cold drafts, freezing pipes and increased energy costs.

 
Exposed earth contributes a lot of water vapor into the crawl space air. The earth is damp, and as that damp soil releases moisture into the air, the water vapor moves upward into the house. In most climates where there are dirt crawl spaces, you can never dry the earth and this invisible stream of water vapor from the exposed soils in a crawl space goes on indefinitely. In fact, water itself does very little to destroy a home with a dirt crawl space. The water seldom - if ever - touches any of the parts of a house that gets ruined, like floor joists, sub floor, and sill plates. It's the water vapor, also known as relative humidity (RH), that causes mold and destroys the house.

 
The solution?  In our experience a permanent vapor barrier sealed at the seams combined with an adequate dehumidifier system set to a humidistat is the best approach to prevent moisture from taking over your home. It is usually best to close all vents and air seal the perimeter around rim joist and sills. Also make sure the area is free of leaking pipes and if needed have a working sump pump in low areas. It is also wise to improve exterior drainage and to install gutters to drive water away from the structure.

To learn more check out this article from www.advancedenergy.org:  To Vent or Not to Vent

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