Where Do I Look For Mold In My Home?

Mold is viewed as a four-letter bad word to most homeowners. Between watching HGTV, the news or hearing of a neighbor that has dealt with mold issues, we get calls from homeowners all the time inquiring about mold growth. A question that is most asked is where do I look for mold in my home? While mold/microbial growth can occur in any area of your home where moisture or high humidity is present, I have narrowed it down to two main locations to look for potential growth.

Go Down Below

The first place I advise people to look for microbial growth is in their basement or crawlspace. Building science experts claim up to 50% of your indoor air comes directly from your basement or crawlspace. Areas that are located close to or underground are likely to be exposed to moisture. Western Pennsylvania is home to incredibly old structures. On a weekly basis Mold Medics assesses homes and building that were constructed in the late 1800’s and early 1900’s. The foundations of these buildings are often made of sandstone or fieldstone. Waterproofing these basement areas was probably not a main concern when they were built. 

Even newer homes are subject foundation issues. Settling, poor grading, clogged gutters and defective downspouts do not discriminate on the age of the home. Our region has seen heavy rains the last few years and with that comes more moisture in the ground. The excessive ground moisture can seep into basements and crawlspaces. This seepage can lead to a raising of humidity levels or wet building materials and contents. 

Common places to check in basement areas are the corners, along the bottoms of all walls and the ceiling joists. Using a flashlight or the light on your phone, shine the light across surfaces. By holding the light perpendicular to the surface, you can uncover surface growth on varies building materials or contents. If any moisture is entering your basement or crawlspace and is not drying fast, you will most likely have some amount of growth.

Look Up High

Another place I always tell clients to look for potential growth is in the attic. Just as air rises from your basement and makes up a significant portion of your indoor air, your attic receives a lot of air from inside your home. Your home is like a chimney, air rises. This phenomenon is called the Stack effect. 

Attic Mold
Mold Growing in Attic

Ideally your attic space is perfectly air sealed and properly insulated. This just is not the reality and I have yet to assess an attic that has been properly sealed. Pull down attic accesses, canister lights, chimneys, plumbing stacks and several other penetrations allow air to enter the attic space. When this thermal barrier is breached problems occur. Warm moist air from inside the home rises and escapes into the attic area. The attic area is typically not conditioned and is cold (as it should be). When warm moist air meets a cold environment, moisture is created. Think amount a cold beer or soda can in summer and the condensation that occurs when you sit it out on a hot day. When temperature differentials occur, moisture develops. 

Specifically, in the North East where we are located, we see issues in late fall, winter and early spring. We get a spike in calls every year during this time frame. Homeowners enter the attic to access holiday decorations that are stored in the attic. Upon entering the space frost or moisture is observed. Nails with frost, wet sheathing and drip marks on insulation are all signs that warm moist air is leaking into your attic space. Warm air entering the attic can also heat the roof and melt snow that is setting on the exterior. This melting of the snow can cause a phenomenon known as ice damming. Icicles are a great indicator this is happening. All these issues can cause microbial growth or rot.

Water World: Bonus Locations

Any area in your home were moisture is located has a potential for microbial growth. Check all bathroom areas. Assess grout and caulking in your shower or bathtubs. Open and look under all sink to ensure pipes are not leaking. Check under your kitchen sink as well. Laundry areas are a notorious source of moisture and microbial growth. Check your washer’s drainpipe and your dryers exhaust vent. There is no life without water. Check all areas of your home where water exists for potential mold growth.

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