What to Do If You Find Mold During Renovation

Plan to Find Mold During Your Home Remodel

If you discover mold during a home remodel, stop work immediately in the area. It’s important to find the moisture source that caused the mold and determine whether the mold can be safely handled on your own or if professional remediation is needed.

What’s Covered:

Why Mold Shows Up During Remodeling
Is Mold Dangerous?
What to Do If You Find Mold During Renovation
Delays, Costs and Insurance
DIY vs. Professional Mold Response
How to Prevent Mold in Future Renovations
Mold Remediation Help

It’s demo day. The excitement builds until you spot a fuzzy black patch behind the drywall. Mold wasn’t part of your renovation plans, but now it’s front and center.

A mold problem can delay your renovation project by days or weeks, and add to your renovation costs. It can also expose your family to potential health issues.

In the southwest Ohio area, many homes hide a history of moisture issues because of:

• Humid summers 
• Aging housing stock (more than half built before 1970), 
• Past flooding events (recently, 2011, 2015, 2018 and 2019, with 2025 also seeing historic rainfall and flooding).
• Past maintenance/mechanical issues that were not properly remediated

So, when renovations begin, so does the reveal and the risk of mold. 

Why Mold Shows Up During Remodeling

Remodeling exposes underlying excess moisture issues that fuel mold growth.

Home renovation projects often come with tearing out drywall, replacing flooring, or opening up attics and bathroom walls. These are all places where moisture can accumulate and remain undetected for years. When you disturb these areas, you may also release mold spores that were previously sealed away.

• What to check for: Musty odors, black or greenish stains behind tile, soft or crumbling drywall, or dark streaks on wood framing.

Common moisture problem culprits that cause mold in southwest Ohio include:

• Leaky toilet wax rings (especially in homes from the 1960s to 1980s)
• Poor attic ventilation, which traps moisture after heavy snow melt
• Bathroom ceiling fans that do not adequately remove excess moisture or are improperly vented
• Slow pipe leaks and older plumbing hidden behind walls, under sinks, under flooring or behind appliances 
• Basements are also a common source of moisture due to sump pump failures and flooding.

Is Mold Dangerous?

Yes, mold can be dangerous, especially during renovations, when the spores get stirred up and become airborne.

Mold exposure can trigger health issues like coughing, congestion, throat irritation, rashes, and asthma attacks. People with allergies, asthma, or weakened immune systems, including children and older adults, are at higher risk (CDC).

Even a small patch of mold can lower your indoor air quality and spread through your HVAC system if not contained quickly.

• You might like: Signs and Symptoms of Mold Exposure

What About Black Mold
Not all black-colored mold is toxic. Even Stachybotrys chartarum, while often called “toxic black mold” due to potential mycotoxins, hasn’t been proven to be more harmful than others in typical home settings. Symptoms and health risks can vary based on individual sensitivity (Harvard Health). It’s important to remember that any type of mold can potentially affect your health.

What to Do If You Find Mold During Renovation

Act quickly and carefully to contain contamination and plan safe mold removal. Whether doing a DIY project or contracting a professional remodeling company, follow these steps if you discover mold during your project.

Step 1 – Pause Without Panic
Stop work in the moldy area immediately. Shut off any HVAC systems to prevent the system from circulating mold spores throughout your living space. If you’re doing it yourself, contain the space with plastic sheeting and painter’s tape to prevent cross-contamination. Garbage bags can be used if plastic sheeting isn’t readily available.

Step 2 – Document Everything
Take clear photos, videos, and moisture meter readings (if available). This documentation supports insurance claims and gives professionals the information they need to develop a safe and effective mold remediation plan. (See insurance info below).

Step 3 – Identify the Source
If you can’t visually identify the underlying moisture issue, use a moisture meter or thermal imaging to locate the problem. In the Dayton and Cincinnati areas, basements, attics, and old bathroom fixtures are common sources of hidden moisture intrusion. If you are not experienced with moisture meters or thermal imaging, it’s time to call a professional for a thorough moisture and mold assessment. 

Step 4 – Call the Right Help
Look for companies with IICRC certification. These professionals have training on how to contain contamination and safely remove mold-contaminated materials. 

Step 5 – Remediate, Then Resume
A qualified team will assess the situation and discuss treatment options and cost with you. The treatment plan may include setting up containment zones, running HEPA air filtration, and removal or treatment of porous materials like drywall, flooring, and insulation. 

Step 6 – Prevent a Repeat Before Closing Walls
Ensure all moisture problems have been fixed and that all materials and structures are dry before closing the wall with drywall. Improve ventilation with upgraded bathroom fans, vents, or even a dehumidifier to maintain healthy humidity levels. 

Delays, Costs and Insurance

In the Dayton and Cincinnati areas, the average turnaround to clean up mold is 3 to 10 days. Moderate remediations typically range from $1,500 to $5,000. However, costs can range from as little as $500 for small jobs to $10,000+  for more extensive remediation and repairs.

Please note, mold remediation costs vary based on the type of mold, its location (such as an attic or basement) and the condition of your property.

Does My Insurance Cover Mold Damage?
While some homeowners may have mold coverage, most insurance carriers in Ohio typically offer no mold coverage or limited coverage, so call your agent directly before filing a claim.

Contact your insurance company to find out if mold removal is covered under your policy and how much they’ll pay. Coverage and limits vary by policy. Mold caused by delayed maintenance or floodwater is not typically covered; however, specific flood insurance policies may cover floodwater mold.

Professional remediation companies, such as PuroClean Emergency Services, will guide you through the process, whether it’s covered by insurance or is a self-pay project.

DIY vs. Professional Mold Response

Know your limits. What seems like a small mold issue can quickly become a costly mistake.

Some minor mold contamination can be cleaned safely by homeowners, only if:

• The area is under 10 square feet
• The mold growth is on hard, non-porous materials (like metal or tile)
• The area does not involve mold caused by contaminated water (sewage and floodwater)

In these cases, use rubber gloves, a mask, and follow EPA-recommended cleaning methods. But proceed with caution.

In most home remodel projects, especially in older Dayton and Cincinnati-area homes, the contamination is more extensive, sometimes hidden in crawl spaces, behind walls, or under old flooring. Attempting DIY mold removal without proper protection or knowledge can spread spores, trap moisture, and lead to further mold growth.

How to Prevent Mold in Future Renovations

Whether it’s a bathroom renovation, kitchen remodeling, or window replacement, moisture control is key.

To prevent mold before it starts: 

• Before further renovations: Perform a visual mold inspection in known high-risk areas (especially if your home has experienced water stains or flooding).
• During demo: Remove any mold-contaminated materials properly, especially contaminated ceiling tiles, wood, or insulation. Ensure everything is completely dry before installing new materials.
• During reconstruction: Prevent moisture intrusion by properly caulking and adding proper ventilation, like bathroom fans.
• After completion: Monitor humidity levels and repair any signs of leaks quickly, especially around pipes, ceilings, and the foundation.

Mold Remediation Help During Remodeling

Don’t let mold slow down your remodel or risk your family’s health. Call PuroClean Emergency Services.

Based in Moraine, OH, PuroClean Emergency Services is the trusted partner for homeowners and contractors in southwest Ohio.

• IICRC-certified technicians trained in mold removal and water damage restoration.
• Clear, insurance-ready documentation to help streamline your claim.
• Compassionate, knowledgeable support from start to finish.

Call PuroClean Emergency Services today at (937) 401-9700 for fast, reliable mold remediation that restores confidence in your home and your project.

We serve the Dayton Metro area to Greater Cincinnati, including Kettering, Oakwood, Piqua, Centerville, Mason, Eaton, Springfield, Beavercreek, West Chester, and surrounding areas.