
Top 4 Reasons Mold Grows In Your Attic!
Why Does Mold Grow In My Attic?

Valor Mold are experts at mold detection, removal and prevention. We specialize in mold in the DC Metro area.
To date, we have provided you with many informative articles and facts about mold designed to answer the following questions:
- Why is mold a concern? Learn more.
- How do I determine if mold is making me sick? Learn more.
- Where is mold growing in my home? Learn more.
- What happens when my home is inspected for mold? Learn more.
- How much will it cost to remove mold from my home? Learn more.
- What steps are taken to remove mold from my home? Learn more.
- Why should I get a mold inspection when I buy a home? Learn more.
- Is the air inside my home making me sick? Learn more.
- Should I be worried about black mold? Learn more.
- Can mold in my crawl space impact the air I breath in my home? Learn more.
- How do I prevent mold after my home is flooded? Learn more.
Continuing with our quest to answer questions about mold that we receive, the purpose of this article is to answer the following question: Why does mold grow in my attic?
As the article reveals, there are four common reasons why attics develop mold.
Top 4 Causes Of Mold Growth In The Attic

#1 A Leaking Roof
If you have a roof leak, you may see water on your floors and water stains on the ceiling. The good news, you know that you have a problem.
However, if you have a roof leak and it goes unnoticed leading to moisture accumulation in your attic, this will eventually lead to mold growth that you may not even know exists.
This is the reason it is important to inspect your attic several times each year, just to make sure that there is no moisture buildup.
- Check for discoloration of insulation and wood (e.g. rafters, sheathing, joists, attic side of fascia boards, etc.).
- Check roof valleys (i.e. where two roofs join at an angle), which are highly susceptible to roof leaks.
- Observe skylights, chimneys, attic windows and any portion of the attic/roof where dissimilar materials join each other (including flashings). These places are hotbeds for potential moisture intrusion.
- If you have a vapor barrier installed, check for condensation. Although this is not really a roof leak, it is nevertheless a sign of a moisture problem. And moisture problems lead to attic mold problems!
- Make sure there are no leaks coming from and around attic plumbing stacks.
The first step to addressing the moisture cause is to get your roof repaired, then contact Valor Mold to remove the mold.
#2 Missing Insulation or Improperly Installed Insulation
The quest to save money on heating and cooling bills motivates many Do-It-Yourselfer’s to install more insulation in their attics.
Unfortunately, if the wrong kind of insulation is chosen or if it is installed improperly, this can cause moisture from the lower levels of your home to rise and get trapped in the attic.
As we have written before, the primary cause of mold growth is moisture. Your attic is made of the food mold loves to feed on.
With respect to the type of insulation, if you are layering insulation on top of other insulation, make sure you do not use the kind that has paper or foil backing because it acts as a vapor barrier and can trap moisture in the insulation.
Before you decide to add more insulation to your attic, determine if you need more first. If you are unsure, contact a professional.
#3 Inadequate Attic Ventilation
One of the problems we have encountered in our projects is the fact that insulation is blocking the ventilation ducts that distribute air in the attic.
The lack of ventilation is another major cause of mold growth in your attic.
Air travels up to the attic meaning activities such as cooking, bathing, showering, etc will produce moisture that will makes it way up to the attic. If there is poor ventilation, the moisture gets trapped in the attic and can lead to mold problems.
Check your soffit vents and make sure they are free of insulation, bird nests, and other debris that could be blocking them and preventing proper air flow.
If you are unsure if the ventilation is ideal in your attic, contact a home inspector or give us a call so that we can take a look.
#4 Fans Vented Into The Attic
Mold will grow if there is moisture, food, and warmth.
Poor building practices occur when the dryer vents, plumbing vents, kitchen or bathroom fans are vented into the attic.
Dryer exhaust vents, kitchen exhaust fans and bathroom exhaust fans are designed to pump moisture out of your home. Make sure that they are vented to the outside of your home and not in the attic.
Plumbing stacks in the attic can also be a source of condensation, which can lead to attic mold growth. Plumbing stacks can also emit hazardous gases, so make sure that they too do not terminate inside the attic.
If any of your vents are routed into the attic, hire a reputable contractor to re-route the vents to the outside of your house.
Concluding Thoughts On Why Mold Grows In Your Attic!
In the video below our President, David Myrick, explains why mold grows in your attic.
Once the cause of your attic moisture issues are identified, then the next step is to determine if you have a mold problem.
Mold is nature’s recycler and will grow and proliferate when moisture is present.
Condensation in an attic, heat and humidity from household activities (cooking, showering, etc.), and the fact that the attic provides an excellent food source for mold, provides the ideal conditions.
All mold needs to grow is 24 to 48 hours and as long as the proper conditions exist, it will continue to proliferate.
If you do find mold in your attic, DO NOT use bleach or try to kill the mold!
The first step is to contact Valor Mold for a mold inspection and air quality test.
During the inspection, tape or swab samples of suspected mold may also be taken and sent to a micro-biology lab.
Once the type of mold and spore count is determined, we will provide with a scope of work on the best way to remediate the mold in your attic.
Got Attic Mold Questions?
Questions? Call 571-210-2040 or send us an e-mail. We look forward to serving you! 🙂
What’s Lurking In Your Attic Infographic

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— Valor Mold (@ValorMold) August 24, 2016
1 Comment
I really thought it was interesting how many things factor into mold in the attic. The biggest one in my mind is the leaking roof. If you have water leaking into your roof, and the heat causes it to become moist, it would seem to me that that would be a great place for mold to start growing. I really think at that point it would be a good idea to call an mold removal company.