Mold Prevention Guides and Tips

Pointers from IAQ Environmental

1. Ice dams, during cold and snowy winter-make sure all gutters and downspouts are kept clean and free of ice and snow. We have seen many houses with water damage due to ice dams this year.

2. Check all hose and fittings on washing machines, replace if old, leaking, or kinked and turn the water supply off if leaving for extended times. Remember, mold will start to grow in as little as 24 hours when moisture is present.

3. If basement walls finished with drywall, install vents near the floor and ceiling to allow airflow within the borders (the more vents, the better). If installing sheetrock in a basement below grade (not recommended), raise the sheetrock a few inches up off of the floor (sheetrock acts like a sponge).

4. If you have storm windows, make sure the weep holes have not been painted over. Weep holes engineered for water to drain out from behind the storm window and the interior window.

5. With the melting of all the snow from this past winter, make sure all basement floor drains are clean and, of course, free of debris.

6. Check the ground near the foundation to ensure the water runs away from the house and not down a cellar window or bulkhead.

7. Before the cooling season starts, check central air systems. Ensure the water tray is clean and the drain is free of debris. Also, clean or changes air filters.

8.Spring time is perfect for checking the roof to ensure the harsh winter has not loosened shingles and flashing around vent pipes and chimneys.

Mold Prevention Tips

• Clean and dry wet or damp spots and wet, non-moldy materials within 48 hours.
• Four words summarize what done effectively, efficiently, and safely remove, remediate, and decontaminate molds:     
• (1) CONTAIN the mildew from spreading into uncontaminated areas;
• (2) KILL the molds;
• (3) REMOVE the dead molds; and
• (4) PROTECT the cleaned out areas against future mold infestations.
•  
• Fix leaky plumbing and leaks in your building as soon as possible.
• Watch for condensation and wet spots.
• Do not allow sprinklers to hit buildings.
• Inspect and repair window seals and flashing.
• Locate moisture-producing appliances to vent outside when possible
• Maintain routine building HVAC checkups and clean as scheduled
• Monitor moisture problems to prevent mold growth.
• Stop and repair sources of water intrusion or accumulation immediately.
• Avoid moisture from condensation by increasing surface temperature or reducing the moisture level in the air. Rise surface temperature, insulate, or increase air circulation. To reduce the air’s humidity, repair leaking pipes, improve ventilation. For example (outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
• Maintain heat ventilation and air conditioning (HVAC) drip pans clean, flowing properly, and unobstructed.
• Maintain low indoor humidity – below 60 percent relative humidity (RH), ideally 30 to 50 percent if possible.
• Never let concrete building foundations continue wet. Drainage should slope away from the building. 

Mold Prevention

Importantly, keep in mind for preventing toxic mold is that fungi and mold need a moist, wet, or damp environment to grow. Maintain a clean, dry home or workplace, and dangerous mold species cannot begin to grow. Unfortunately, it is often complicated to distinguish between toxic molds and those that don’t pose a risk. All types of mold appear quite similar—black or grayish sooty patches. Toxic molds that thrive in the home. Most of the time, remove them through regular cleaning before they grow to a size to pose a threat.

Ay type of mold found in a particular home, the relative safety of those inside depends on the mold manifestation size. The danger occurs when the decay reaches a length of 2 square feet. Besides, the concern is if mold has infested household items like insulation, drywall, or carpet. If so, these materials need immediate extraction. The culprit of dampness or wetness solve. Remove and replace these items, and it is best to use a non-cellulose and low nitrogen replacement material.

The mold should come off with simple scrubbing (individuals should protect themselves with eye protection, rubber gloves, and carbon filter respirators). The mold that dried ought not to be scratched because it expands the odds of delivering poison, conveying spores into the air.

Locations in and around homes that can create a hazardous environment include leaking or busted pipes, windows or older doors that fail to provide seals, roofs that leak, and any cracks or holes in the building. If flooding has occurred, it is crucial to ensure that the water is thoroughly dried up to avoid festering water or dampness. Besides, reducing the humidity through a dehumidifier can prevent the growth of dangerous toxic molds.

All building’s scheduled maintenance includes:

Inspection for water leaking.

• Defective seals around windows and doors.
• Checks for visible mold in the building’s moist or damp parts.

Moisture investigations improve the prevention of mold or fungi. 

A mold assessment by a qualified mold inspector ensures the building is free from mold. 

 

Mold Prevention: Trades Can Work Together

By Bruce M. Small, P.E.

 

The mechanisms of mold growth  

Several published articles (e.g., Toxic Mold: A Common-Sense Approach to an Uncommon Challenge, Walls and Ceilings, July 2002) have described mold’s dependence on moisture. 

Firstly, an essential purpose of a building is to prevent moisture from intrusion into our facilities—we all prefer a roof without leaks. Well-built and well-maintained buildings don’t allow wetness to occur. A moisture investigation will help track down the source.

Still, many buildings do get moisture intrusion inside in several ways:

• Water can fall or drip in from leaking roofs or exterior walls (by gravity).

• Water is sucked in through exterior materials subjected to rain (by capillary action) or through basement materials to wet earth.

• Humid air vented in (or out) through cracks in the building envelope (air leakage).

• Water vapor can seep in and out slowly by diffusion, molecule by molecule. It travels from a saturated humid area to a reduced humid area.

• Water spilled (plumbing leaks, sloppy kitchen work, playful children in bathtubs, plant growth, faulty appliances, excessive mopping, fire fighting, etc.).

The ordeal for any building designer and owner is to leave out, deflect, or otherwise contain all of these moisture flows so that it doesn’t cause damage. Combing common sense and modern building science can effectively meet this challenge in actual practice.

 How do buildings with mold problems?

Sometimes, mistakes are made when a building. For example, a missing roof enclosure system allows rain to intrude a building under violent wind conditions. Or plans that work well in one climate and are mistakenly specified in another (e.g., homes designed for operating in cold weather conditions don’t make good homes for air conditioning in humid southern climates).

Sometimes, the building plan is excellent, but the contractor doesn’t follow it closely enough. The architect or building inspector doesn’t catch mistakes.

For example, school buildings have developed moisture problems because of pavement grade to the surrounding playground. The area sloped toward the building rather than away from the building.

 Buildings are purposed other than for what they originally designed. For instance, a building formerly used for cheese making or flower cultivation may lack adequate ventilation when converted for an industrial or hobby activity.

Good buildings fail because of lowered budgets, away landlords, poor management, or different causes. Some schools have high humidity and low indoor air quality because ventilation fans or exhaust vents have broken and have not been repaired.

Avoid a costly mold remediation by adhering to strict moisture control.

Why utilize a systems approach to building plans?

Form emerges in structures because numerous individuals get things done without taking a gander at the master plan. “Building science” and “frameworks approach” are words used to portray another method of planning, fabricating, and working structures that maintains a consistent spotlight on the final execution of a design.

The University of Toronto’s Building Science Program indicates in its continuing education curriculum that neglect to examine the bigger picture can lead to building failure: “Engineer schools typically teach building science in a broken manner, including small elements of material science, structural design, and mechanical systems. Architecture schools usually take a more integrated approach to teach building design. Building science issues are too technical, demonstrating an education gap within engineers’ and architects’ ranks in the construction industry. The building must be considered a system—the interaction of the many different elements and components of a building and the environments. =

The systems approach to building science allows the interdependence of the component materials, the mechanical and electrical systems, how the building operates, how the environment affects the structure, and how the occupants use the facility.

Building designers strive to understand each part of the building’s operating characteristics and structure in a systems approach. Changes are not produced in one component material or subsystem without assessing their influence on other attributes of a building’s overall accomplishment.

In a well-specified building, all the materials and subsystems come together to ensure the whole structure goes well, similar to a “team approach” in sports. For an accomplished by establishing good communication among all the designers, builders, and potential users of a building to change any aspect without considering its impact on the rest.

For example, cutting school maintenance budgets to save a dollar can lead to many human illnesses, more expense, and sizeable disruption. Choosing inexpensive materials and building envelope designs can drastically reduce the useful life through wall decaying from moisture intrusion, humidity, and mold growth.

Sometimes, waterproof finishing materials are used in air-conditioned spaces within air-leaky buildings in warm, humid climates to make walls more comfortable to clean. However, using them in this application can confine moisture inside the wall, causing mold growth and drywall rot. Adequate buildings require lots of good thinking before they are built and moved in. Take shortcuts at your danger. 

 Guidelines for avoiding Mold Reproduction 

Use a full rain-screen around the whole building. It seems easy, but there’s a skill to making a building remove all rain possible. Proper protection is required in the outer building layers so that driving rain will not penetrate the structure. The requirements rain-screen materials and more flashing to direct any water that might intrude under lousy weather back to the outdoors with a “drainage plane.”

Building scientists like Joe Lstiburek of Boston encourages that nothing is perfect. One should expect some water leaking and design a building to direct it back out to dry out again.

Buildings work best when there is reasonable foundation drainage, adequate guttering along the roof, and proper sloping of all grounds surfaces and walkways away from the building. Water does not lead to the building below grade level. Inside, adequate drainage is a requirement in areas that use water, such as laundry or utility. 

If flooding, a building may need one or more sump holes and pumps, which engage in a flood situation to keep water from entering a basement below grade.

Older construction allows a great deal of air leakage through exterior walls and ceilings (the building envelope). They used to think this was a good thing because it provided air for the furnace and diluted indoor pollutants. But air entering through the building envelope can allow moisture to collect within the walls and ceilings, depending on the exterior temperature and humidity. In northern (winter) climates, moisture air going out through walls can cause condensation when it reaches the wall’s cold outer layers. In the southern environment, warm, hot, humid outside air leaks inward. It can cause condensation when the air comes air-conditioned materials indoors (for example, the behind the drywall or cold air-conditioning ducts).

Modern buildings use tight wall construction, ventilation, low-emission materials, and deliberate ventilation rather than air leakage through walls and ceilings. If there is a sufficient air barrier in all walls and ceilings, there is no way for humid air to move back and forth across the “building envelope.” Without such humidity migration, there can be no condensation and mold growth inside the walls or ceilings.

All buildings need ventilation to remove unfresh air and excess moisture produced during the normal activities of daily living. Without adequate ventilation, water and indoor pollutants accumulate. With leaky construction, ventilation may be sufficient to remove contaminants but may lead to condensation and mold reproduction. With tight-wall construction using low-emission materials, venting air can be much more efficient and is often combined with energy recovery to trade in the middle of intake and exhaust air.

Utilizing a systems approach and designing high-quality buildings was once a cumbersome and expensive proposition (although never more costly than building failure). Now, we have access to new materials and methods that make it easier to apply the principles outlined above and achieve mold-free buildings.

Overturn old building Mold Methods  

New techniques for building that will prevent mold growth are challenging mold standard building practices throughout North America. For example, it used to be regular practice in warm, humid areas, add HVAC equipment and ductwork in the attic and then ventilate the attic to get extremely hot.

The issue with venting with warm, moist air is getting the humidity out of any cold surface (an example is an unwrapped A/C duct) and combines. Days of dripping lead to mold growth in the insulation and drywall underneath. Eventually, the entire attic and ceiling require the removal and replacing. Some manufacturers recommend the latest practice of sealing the attics in humid climates and applying soft-foam insulation to the roof’s underside, forming a cathedral ceiling. It turns the attic into a dry, conditioned space, significantly improving air-conditioning efficiency and preventing condensation and mold growth.

Designers and building code regulators challenged to rethink their insulation guidelines, including ever-higher thicknesses and R-values in the continent’s colder areas. Since the R-value of insulation is failed by airflow through it, it makes sense that proper insulation in a well-protected wall may be just as good or better than much more insulation in a wall system that leaks heavily.

Hotel owners down south used to resent that vinyl wall coverings replaced every few years. Why? Moisture intruding the building envelope from the outside would penetrate the drywall and condense within it, right behind the wallpaper, impervious to water. Inevitably, the wall covering’s back surface would become black with mold growth and begin to peel. Owners would remove and replace it with the same material.

Now that there is a more excellent knowledge of moisture flow, condensation, and mold reproduction hazards. People are also rethinking the use of vapor barriers, which must be on the insulation’s warm side, not the cold side.

If you add a vapor barrier on the wrong side or both sides, moisture may get sandwiched, and the wall between may never dry out. If a sound vapor barrier used in the right place (warm side) combined with a well-sealed building envelope, there is a decreased moisture travel across the wall or ceiling.

In a well-designed wall, any excess moisture that does penetrate through or around the vapor barrier can proceed through the wall by diffusion and causes no defects. 

In warm climates, low amounts of excess moisture can, for example, be easily handled by the drying effect of air conditioning if the humidity is allowed to travel entirely penetrate the wall into the interior space. In cold climates, excess moisture can reach the exterior without causing damage if the wall’s outer layers of protection from moisture flow.

Because the walls and ceilings are airtight, we are not as dependent on vapor barriers before circumventing condensation and mold reproduction. In fact, in some climates and applications, vapor barriers may turn out to be unworthy and even useless.

Remediate existing buildings

Mold growth prevented new construction by prudent design, right thinking, and coordination among the many parties involved. Buildings that have developed mold problems are properly remediated if appropriate care is taken. The following example illustrates how moldy buildings returned to use.

Problems soon after the occupation of three intermediate schools in Texas in flare-ups of mold allergies. Mold inspected behind wall hangings and marker boards in several rooms. An investigation revealed several flaws that allowed water to penetrate the walls.

The consultants recommended that all existing materials are containing mold is discarded. The existing exterior building envelope is modified to control moisture entry, accumulation, and removal properly.

Repairs made to the roof, gutters, downspouts, grading, windows, flashing, and weep-holes ensure that rainwater could no longer penetrate the walls or ceiling.

Drywall growing mold disregarded. The combination of the interior and exterior of the exterior masonry walls were moisture-proofed. Three inches of foam insulation application directly to the exterior masonry veneer’s inside the fascia, and interior walls built right. 

The cardinal rule in avoiding involvement in a lawsuit is: “Don’t do anything you know is dead wrong.” Painting over moldy drywall in the hope that the mold will go away is one such example. I am installing the wall finish before the roof is sealed. In buildings, covering up mold problems doesn’t work—mold will continue to thrive. It will penetrate to the surface again.

Subcontractors will not take full responsibility for the building’s overall performance. However, their reputation may still suffer if others haven’t done their job correctly. A beautiful drywall job was destroyed rapidly by leaking windows. The most decorative ceiling can be tainted in minutes by plumbing leaks. Specified vinyl wall coverings in the wrong place won’t aid the wallpaper installer in marketing his expertise. And all contractors distort their reputations if the building goes moldy. W&C

 

Reference: Bruce M. Small, P.E., is co-founder and director of the Envirodesic Certification Program, which develops and promotes buildings, products, and services that contribute to healthy indoor environments.