Mold inside walls is a common problem that can affect any home. If left unchecked, mold can cause serious health issues and structural damage. Thankfully, with the right tools and techniques, you can fully remove mold from inside your walls and prevent it from coming back.

What Causes Mold Inside Walls

Mold spores are present in virtually all environments. Mold can begin growing inside walls when excess moisture gets trapped in the wall cavity. Common causes include:

Plumbing leaks – Slow water leaks from pipes or fittings can soak walls and provide ideal conditions for mold.
Flooding – Flood waters that contact the base of walls can seep moisture into wall cavities.
Rainwater leaks – Leaky roofs, windows, or exterior siding can lead to moisture accumulation inside walls.
High humidity – Consistently high indoor humidity encourages condensation on walls that enables mold growth.
Poor insulation – Insufficient insulation allows exterior wall temperature differences that add moisture.
Clogged gutters/downspouts – Prevent proper drainage away from the structure.

Any prolonged moisture issue can potentially cause mold inside walls. It is important to address water intrusion promptly before mold becomes established.

Dangers of Mold Inside Walls

Mold may initially go unnoticed if it is developing out of sight inside walls. Prolonged mold growth poses various health and home risks:

Allergic reactions – Mold spores can trigger respiratory issues, especially for those with asthma or allergies.
Toxicity – Certain molds release mycotoxins that have toxic effects throughout the body.
Structural damage – Mold can deteriorate the structural integrity of wall materials over time.
Spreading spores – Unchecked mold will multiply and spread spores to other areas of the home.
Devalued property – Extensive mold can decrease property value and make a home harder to sell.

Catching and removing mold in walls early is essential to avoid severe impacts to health, home value, and the building itself.

Inspecting for Mold Inside Walls

Suspecting you may have mold inside your walls? Start by thoroughly inspecting for common signs:

Visible Growth

Discolored splotches or black/greenish flecks on interior wall surfaces.
Peeling or bubbling paint and wallpaper.
Warping of wall materials.

Musty Odor

A persistent musty, earthy smell, especially after rain or high humidity.

Moisture Readings

Use a moisture meter to probe walls for elevated readings that indicate excess moisture.

Condensation

Beads of condensation forming on inner wall surfaces.

Pests

Swarms of flies or signs of insects attracted to mold growth.

Thoroughly inspecting interior and exterior walls enables detection of any visible mold signs. Be sure to probe any questionable areas with a moisture meter. If high moisture is found and mold growth is suspected inside the wall cavity, further investigation and remediation will be required.

How to Test for Mold Inside Walls

If your inspection reveals probable signs of hidden mold, confirmation testing is advised before beginning the removal process. Testing helps identify the exact location of mold growth and the species present. Common mold test methods include:

Air Testing

An indoor air quality (IAQ) test can detect elevated levels of mold spores in the air, indicating active mold growth hidden in walls. Consider professional air testing if there is suspicion of toxicity.

Swab Samples

Surface wall cavity swab samples can be collected and sent to a mold testing laboratory for microscopic analysis to identify mold species.

Bulk Samples

Removing a small piece of wall material allows for lab testing to positively confirm mold growth hidden within wall materials.

Infrared Camera

Infrared thermal imaging can detect areas of walls with elevated subsurface temperatures that may signal elevated moisture ideal for hidden mold growth.

Professional mold testing provides confirmation of whether significant mold growth is present within walls. If considering mold removal by a contractor, testing will help assess the proper remediation scope.

How to Remove Mold From Inside Walls

Once mold inside walls is confirmed, proper protective measures and removal techniques are essential for health safety and to ensure the mold is fully eradicated. Here are key steps:

1. Prepare the workspace

Seal off the affected room by closing all doors and covering vents.
Wear protective gear – gloves, goggles, mask rated for mold spores.
Cover floors and furnishings with plastic sheeting.

2. Identify and fix the moisture source

Locate and fully repair any water leaks or moisture intrusion issues.
Reduce interior humidity and improve airflow if needed.

3. Remove contaminated materials

Using a utility knife, cut away an access hole into the affected wall cavity.
Remove any visibly contaminated drywall or insulation.
Vacuum out cavity using HEPA vacuum attachment.

4. Treat the affected area

Scrub exposed wall surfaces with antimicrobial cleaner.
Use a fungicide spray or mold-killing primer inside the cavity.

5. Allow walls to fully dry

Increase airflow and dehumidification in the area.
Use drying equipment like fans and dehumidifiers.
Check moisture content using a meter.

6. Replace damaged materials

Install new insulation and cut drywall patches to fit.
Mortar and seal patched walls to prevent recurrence.
Prime and paint interior surfaces with mold resistant paint.

Be sure to follow all protective measures when disturbing moldy materials to contain the spores. Properly drying the cavity and replacing contaminated materials reduces the chances of future mold recurrence. Consider hiring a mold remediation contractor for large affected areas or signs of toxicity.

How to Prevent Mold Inside Walls

Preventing excess moisture is key to avoiding mold inside walls. Here are important prevention tips:

Maintain plumbing in good repair without any leaks.
Use bathroom exhaust fans and vent clothes dryers outside.
Install and monitor humidity-control equipment.
Redirect rainwater drainage away from the home’s foundation.
Keep gutters and downspouts clean and draining properly.
Promptly repair any roof or window leaks or exterior water damage.
Ensure crawl spaces have a thick vapor barrier and proper ventilation.
Avoid over-insulating exterior walls in cold climates.
Allow airflow and sunlight exposure behind furniture placed against exterior walls.

Careful moisture control and prompt repairs are crucial to prevent ideal conditions for mold growth in walls. Be aware of any musty odors or visible moisture signs and immediately investigate for any underlying intrusion issues. Addressing problems early is key to keeping your walls mold free.

FAQs About Removing Mold From Inside Walls

How do you know if you have mold inside walls?

Common signs of mold inside walls include a persistent musty odor, moisture visible on wall surfaces, peeling paint or wallpaper, and potential mold growth visible at electrical outlets or vents. Moisture meter readings above 15% indicate excess moisture ideal for hidden mold.

Can mold inside walls make you sick?

Yes, mold exposure can cause respiratory issues like wheezing, runny nose, and eye irritation. Toxic black mold can even potentially lead to dangerous mold poisoning. Those with allergies or compromised immunity may be most vulnerable.

How can you tell if mold is behind drywall?

Carefully cut a small section of drywall to view the cavity. Signs of mold include black or greenish staining, a musty smell, and visible mold growth on insulation or framing. Swab and air samples can also help detect hidden mold.

What kills mold behind walls?

To kill mold inside walls, use a fungicide spray or antimicrobial wash containing bleach or clove oil mold-killing ingredients. Be sure to wear proper protective gear when using strong chemicals on mold.

Does homeowners insurance cover mold removal?

Homeowners insurance may cover mold removal and repairs if the mold was due to a sudden covered loss like water damage from burst pipes. Gradual mold growth from humidity or deferred maintenance may not qualify for coverage. Check your policy terms.

Can you paint over mold?

Never attempt to simply paint over visible mold growth. Painting does not remove the mold and may actually contribute to spreading spores. Always remediate the underlying moisture issue, fully remove mold, and use primer intended for mold-prone surfaces.

Conclusion

Left unchecked, mold inside walls can eventually become a toxic and destructive force within the home. But armed with protective gear, moisture meters, antimicrobial solutions, and proper removal techniques, you can successfully eliminate mold from your wall cavities and interior living spaces. By addressing water intrusion promptly and maintaining indoor humidity at bay, you can keep mold from taking root behind your walls and avoid the headaches of serious removal and repairs down the road. With diligent prevention and early intervention, your home’s walls can stay dry and mold-free for good.

How to Remove Mold From Inside Walls: Step-By-Step Guide

Mold growing inside walls poses serious health risks as spores spread throughout the home. Remediation requires removing contaminated materials and killing remaining mold to prevent regrowth. Here is a step-by-step guide to safely remove mold from inside walls:

1. Prepare and Protect

Seal off affected room by closing doors and covering vents. This helps contain mold spores.
Wear protective goggles, respirator mask, gloves, and full-body coveralls. N-95 masks at a minimum are recommended to filter mold spores.
Cover floors and furnishings with plastic sheeting to avoid further contamination.
Set up containment zones and post warning signs if toxic black mold is suspected.

2. Eliminate Excess Moisture

Identify and fully repair any water leaks or moisture source encouraging mold growth.
Open windows and use dehumidifiers and fans to dry out interior air and building materials.
Maintain humidity under 50% until remediation is complete.

3. Inspect and Test for Mold

Visually check interior walls for stains or mold growth.
Use moisture meter to detect elevated moisture in wall materials.
Consider professional air testing or lab samples to confirm mold and identify species.

4. Cut Inspection Openings

Outline inspection openings with painters tape to minimize surface area.
Carefully cut out a 6-8 inch wide opening using a drywall knife or oscillating tool.
Inspect the exposed cavity for mold on insulation, framing, wiring etc.

5. Remove Contaminated Materials

Pull out any moldy insulation for disposal.
Cut out affected drywall 1-2 feet past visible mold staining.
Vacuum out cavity thoroughly using HEPA filter vacuum.
Place contaminated materials in sealed bags for disposal.

6. Clean Affected Areas

Scrub mold on exposed framing using detergent or fungicide wash.
Rinse surfaces thoroughly and let dry completely.
Mist anti-microbial shield or fungicide spray in exposed cavities.

7. Install New Materials

Install new drywall patches and insulation once surfaces are dry.
Seal seams and openings thoroughly with mold-resistant caulk.
Prime and paint patched areas with interior mold inhibiting paint.

8. Final Cleanup and Reoccupy Space

Wet mop hard surfaces with disinfectant.
Shampoo carpets and upholstery.
Continue monitoring humidity levels.
Follow any restrictions if mold toxicity is a concern.

Proper protective gear is critical when disturbing moldy materials. Completely drying all affected wall materials before rebuilding will help prevent mold recurrence. Seek professional mold remediation if contamination is severe.

How Much Does Mold Remediation Cost?

Mold remediation involves removing contaminated materials, killing remaining mold spores, and fixing underlying moisture issues. Here is what to expect regarding typical costs:

Mold Inspection

Professional inspection fees often range $300-$600 to detect hidden mold and assess remediation needs.

Minor Mold Remediation

For small areas under 100 square feet, DIY mold removal costs less than $500.
Hiring a contractor for minor mold removal typically ranges $1000-$3000.

Major Mold Remediation

Extensive mold growth beyond 100 square feet requires full professional remediation.
Expect $3000-$10,000 for pro mold removal in larger areas of the home.

Specialized Remediation

Toxic black mold raises safety risks and may require extensive containment.
Expect $10,000-$30,000+ for specialized toxic mold removal by certified pros.

Related Repairs

Associated costs for replacing drywall, insulation, carpeting and more that may be mold damaged.
Structural repairs if mold caused hidden timber decay.

Several variables affect the overall expense. Amount of visible mold growth, species toxicity, accessibility, and the extent of repairs or replacement materials all contribute to the total project costs. Maintaining vigilance against excess moisture helps avoid the major headaches and expense of mold remediation down the road.

Choosing a Mold Remediation Contractor

Extensive mold growth often requires professional mold remediation services. Here is what to look for when selecting a qualified contractor:

Reputable Company

Seek established local contractors. Check reviews and complaints with the Better Business Bureau.

Licensed and Insured

Verify required state licensing for mold remediation contractors.
Make sure the company carries general liability insurance and workers compensation.

IICRC Certification

The Institute of Inspection, Cleaning and Restoration Certification (IICRC) provides mold-specific training and certification preferred by many homeowners.

Expert Personnel

Look for Mold Inspector, Mold Remediator, and Mold Technician professional certifications.
Ensure employees are properly trained in safe mold removal techniques.

Detailed Inspection

Contractors should perform a thorough visual inspection plus moisture readings and air sampling to size up the job.

Clear Bid Proposal

Get a written mold remediation plan outlining scope of work, materials, safety protocols, and itemized costs.

Specialized Equipment

Look for powerful HEPA air scrubbers, dehumidifiers, negative air machines, and truck-mounted vacuum systems.

Remediating mold properly requires extensive expertise and specialized tools and safety protocols. Ensure any contractor you consider has specific training and certification for professional mold removal services.

What to Expect During Mold Remediation?

Mold remediation involves extensive cleanup and reconstruction. Expect the following process during professional mold removal:

The containment area will be sealed with plastic sheeting to prevent spore contamination. Negative air machines provide ventilation.
The contractor will cut inspection openings and remove moldy drywall, insulation, carpeting, etc. for disposal based on test findings.
Surface mold on remaining materials is scrubbed and treated with antimicrobial solutions to kill spores. Cavities are misted with fungicide spray.
Containment plastic remains in place during structural repairs. New drywall patches are sealed thoroughly.
HEPA air scrubbers continuously filter spores during demolition and rebuilding. Powerful drying equipment operates until humidity targets are achieved.
Once mold spores are remediated, surfaces are meticulously cleaned and disinfected. Air is tested to confirm mold levels are back to normal.
The affected area remains sealed off until the professional mold remediation company gives the all clear that construction is complete.

The process typically takes 2-5 days depending on the size of affected areas and materials involved. The contractor will implement necessary safety protocols throughout the project. Expect construction mess and noise, with full cleanup and restoration once mold removal is verified.

How to Test for Mold Toxicity

Exposure to toxic mold can cause severe health effects. Here are ways to test if you have dangerous black mold:

Professional Testing

Hire an environmental lab to take air samples or swab samples of visible mold growth. Analysis under a microscope can identify toxic varieties like:

Stachybotrys (black mold)
Chaetomium
Fusarium
Memnoniella
Trichoderma
Ulocladium

DIY Mold Testing Kits

Mail-in kits allow you to easily collect samples to submit for lab analysis. Look for kits that include lab testing fees and detailed instructions.

DNA Analysis

Advanced mold testing can pinpoint mold species by analyzing the DNA. Spore traps or swab samples are taken for PCR DNA-based laboratory testing.

Hire an Inspector

A certified professional mold inspector can identify suspicious mold growth and take proper samples to diagnose toxicity. Some inspectors utilize infrared cameras to locate hidden mold.

If black mold is suspected, get professional testing done immediately and avoid entering the contaminated area. Prompt testing helps assess necessary remediation protocols and potential health risks.

Health Symptoms of Toxic Mold Exposure

Exposure to dangerous types of mold can cause adverse health effects. Recognizing key symptoms helps identify mold toxicity:

Chronic coughing and wheezing
Mucus buildup and watery eyes
Difficulty concentrating or short-term memory issues
Persistent fatigue, lethargy, and headaches
Frequent nausea or vomiting
Skin irritation or hives
Body aches and joint pain
Fever and chills
Sore throat or hoarse voice

Seek medical care immediately if multiple symptoms arise or worsen after spending time in a moldy indoor environment. Be sure to get professional testing to identify the mold species. While symptoms may subside after leaving the contaminated area, toxic mold exposure can potentially lead to long term health consequences. Anyone experiencing concerning symptoms should consult a doctor regarding mold toxicity illness and proper treatment.

Mold Remediation Safety Tips

Mold remediation requires careful precautions to avoid hazardous spore exposure. Follow these important safety measures:

Turn off central HVAC system and prevent air circulation during re