Tag Archives: allergies

Mold in a Crawl Space

This is a slightly revised re-post from our very popular June 2012 blog about mold in crawl spaces.

Summer is almost here, and with the warm temperatures comes more homeowner activity in the yard. A few will even open the door to their crawl space and peak inside. What happens if you find a bunch of mold that seems to be growing on the wooden floor joists under your house?

First, understand that a few different kinds of things that look like mold can also stick to joists. Second, understand that some mold on the wood under your house is normal and to be expected, especially if your crawl space is an ‘open’ design with foundation vents that allow outdoor air into the space. Some mold under the house may be defined as ‘normal fungal ecology’, especially in the southeastern U.S.

If you are reasonably sure that your floor system has mold on it and want to know if something needs to be addressed, you may want to consult with an expert, or be prepared to buy a few measurement tools and learn how to use them. An expert is best defined in this case as someone who can assess the crawl space without bias (i.e., they do not sell sealed crawl systems or perform mold remediation).

The optimal time of year for an expert opinion of a crawl is during summer months. This allows the expert to view the crawl when mold is most active, outdoor humidity levels are up and when the house is using air-conditioning.
Here are the steps your expert should take:

  1. While wearing protective gear, crawl through the entire underside of the house and document conditions with photos of the vapor barrier, foundation walls, floor insulation, joists/sub-floor, and any mechanical equipment (especially air handler & ductwork;
  2. Collect wood moisture measurements of several joists and the sub-floor, especially near plumbing penetrations and near the foundation if moisture is observed;
  3. Check the vapor barrier for tears or gaps that could allow soil moisture to evaporate onto the floor system;
  4. Measure soil moisture content if it appears to be damp. Note if all the soil is damp or just certain areas;
  5. Note any strong musty odor. A crawl space should smell earthy, not musty;
  6. Note any debris such as old pipes, insulation or ductwork lying on the floor. These should be cleaned out;
  7. Warn the homeowner of the danger of storing gasoline-powered yard tools under the house, especially if they are near a gas-fired furnace (we have seen this hazard all too often);
  8. Observe the level of air movement through the crawl space. We often find a ‘dead zone’ near the center of larger crawls, which is usually home to more than the typical amount of fungal growth.

Your expert should be able to provide a report that includes a list of observations & recommendations. Here comes the tricky part – how do you know if the mold in the crawl space is at a normal level and is unlikely to harm the family living in the house?

This is where experience plays a large role. Someone who is new to crawl space inspections may miss something important, make a big deal out of something insignificant, or not know how to communicate their findings very well. Other variables that come into play are the tightness of the duct system under the house, the number of occupants who are sensitized to mold and  claim to be experiencing health effects, and the air quality inside the home. It is important to understand that bacteria or mold in a crawl space will find their way into a house through gaps in the floor system and HVAC components and on thermal air currents that naturally travel upward from the crawl to the attic. An expert should be able to measure the likely impact of mold on your indoor environment or be able to direct you to someone who can.

A final note about the collection of samples from suspect mold in the crawl space. It is not always necessary to know the exact level or species of mold (information lab analysis will provide), however, sample collection is often useful, especially if someone in the home suspects a health issue that could be related. Ask your expert to explain their sampling method and what information they hope to gain by sending a sample into a lab for analysis. An experienced individual will be able to clearly explain why sampling is necessary and how it will guide the process of determining if the crawl space has a normal fungal ecology.


Christmas Trees: a Source of Indoor Mold During the Holidays

A study presented at the annual meeting of the American College of Allergy, Asthma & Immunology in 2007 found that indoor mold increased over a two-week period after a live Christmas tree was placed in the room. The study, which was broadcast on CBS and NBC news, found that airborne mold counts increased from a normal count of 800 during the first 3 days to a high count of 5000 spores per cubic meter of air at day 12.

Although the study was of one tree in one home in the northeastern U.S., allergists from across the U.S. chimed in to agree with the study. Many of the allergists were not surprised by the result given the increase in allergies treated during during the thirty days following Christmas.

ESG has been collecting measurements of mold spore counts inside dozens of homes and businesses across North Carolina during the holidays for many years. Our data suggests that the lone study mentioned above is accurate: indeed, airborne mold counts seem to spike around the New Year and continue to be elevated, especially with a very allergenic mold called Myxomycete. Our office gets a number of calls from people who are suffering from allergies during this time, and in one case a young couple was so affected they stayed in motel until we could help figure out how to reduce the airborne mold counts in their home.

Here in North Carolina, the Fraser Fir is considered the finest Christmas tree, and many families enjoy the tradition of going to the mountains in western NC to cut a live Fraser Fir. What can a family do to help prevent a holiday-dampening allergic reaction? Medical professionals say that vigorously shaking a live tree before bringing it in the house will help. Some people use their leaf-blower to vigorously ‘wash’ the tree with air. Do not wet the tree down, as moisture will activate the mold to grow. Once brought indoors, keep the house around 68 degrees and locate the tree away from any air vents that could disperse the mold around the house. Finally, limiting a tree to a one-week stay inside the house should keep fungal counts low enough for most people to tolerate.

We will discuss the pros and cons of artificial trees in another post in a few days.

Don’t get “floxed”! or how mold sneezes at antibiotics

Walt SchnabelWalt Schnabel is an Environmental Investigator with ESG who assesses an average of ten residential homes every week. Always on a quest to help his clients, this post from Walt takes a look at antibiotics and how they may not always be the best answer to sinus issues.

Every day our office gets a call from someone who is “having sinus issues” or “allergy symptoms”. As an Environmental Investigator, I interact with these clients on a daily basis. One of my questions to clients who have allergies is, “Are you currently taking any medications?” Many of them answer yes, explaining that they are taking antibiotics for their sinus infection or related symptoms.

A recent article in the New York Times titled “Popular Antibiotics May Carry Serious Side Effects” by Jane E. Brody, both amazed and alarmed me. The author discusses a class of antibiotics known as fluoroquinolones. The author states:

“The best known are Cipro (ciprofloxacin), Levaquin (levofloxacin) and Avelox (moxifloxacin). In 2010, Levaquin was the best-selling antibiotic in the United States. But by last year it was also the subject of more than 2,000 lawsuits from patients who had suffered severe reactions after taking it.

Part of the problem is that fluoroquinolones are often inappropriately prescribed. Instead of being reserved for use against serious, perhaps life-threatening bacterial infections like hospital-acquired pneumonia, these antibiotics are frequently prescribed for sinusitis, bronchitis, earaches and other ailments that may resolve on their own or can be treated with less potent drugs or non-drug remedies — or are caused by viruses, which are not susceptible to antibiotics.”

For the full article, visit http://well.blogs.nytimes.com/2012/09/10/popular-antibiotics-may-carry-serious-side-effects/

The CDC also has a section on their website, “Get Smart: Know When Antibiotics Work”, where it states that “Most sinus infections are caused by a virus” and “Sinus infections are rarely caused by bacteria”. The CDC lists the other causes of sinus infections as:


Pollutants (airborne chemicals or irritants such as dust)

Fungal infections

Structural problems within the nasal cavity

A weak immune system

A review of the indoor environment in your home for dust, molds or other contaminants may be the first step to better health!

Tips for Keeping Pollen Out of Your Home


sneezing womanReaders who live in North Carolina know it’s pollen season when they wake up to a yellow car. On a windy spring day we see clouds of yellow pollen billowing through our neighborhood. For those of us who are prone to allergies, this time of year can make our lives quite miserable with sneezing, runny noses and watery, itchy eyes.


 While most allergy sufferers know to avoid being outdoors when the pollen count is high, many do not realize the many ways in which they literally invite the yellow allergen into their home to be inhaled all night long. Here are a few tips to help you fight the pollen battle in your home:


  • Keep windows closed and do not run fans that pull outdoor air indoors. We know it’s nice outside and the urge to open windows is strong, but consider the consequences of introducing all that pollen into your home.
  • Upgrade your furnace filter to paper media with lots of pleats. Leave it in place until the heavy spring pollen season is over, then replace it.
  • Run a HEPA air filter in your bedroom to help trap errant pollen. You can’t possibly keep all pollen out of the house, but keeping the count low where you sleep is very important.
  • Wash your hair in the evening. This will get the pollen out of your hair and help keep your pillow clean.
  • Change your pillowcase frequently during pollen season.
  • Bathe your outdoor pets every day and keep them off the bed! The latter is a good idea all year long as outdoor pets bring all manner of contaminants indoors on their feet and fur.
  • Run a vacuum cleaner over floors every day. Use a vacuum with a sealed HEPA system so you’re not just blowing the pollen off the floor and back into the air.
  • Wash clothing frequently, especially things you wore while pursuing outdoor activities. Clothes can trap lots of pollen against your skin, causing the release of histamine. This release of histamine is what causes pollen allergy symptoms.