What Are Acceptable Moisture Levels in Drywall?

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  • High humidity in your home leads to elevated drywall moisture content levels, creating conditions for mold growth and structural weakening that compromise your walls.

  • Expect to pay $300 to $825 to remove mold from drywall or $2,400 on average for full mold remediation when moisture levels exceed acceptable limits.

  • You can lower humidity in your home by running a dehumidifier, using exhaust fans in bathrooms and kitchens, and improving attic ventilation for better airflow.

  • Hiring a local mold inspection professional provides clear answers through full inspections and indoor air quality testing, helping you plan remediation confidently when moisture becomes a concern.

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Drywall plus water can equal disaster. High moisture levels in your home's drywall weaken it, making it more likely to crumble and increasing the risk of mold growth. But what are acceptable moisture levels in drywall? There's a range, depending on location and your home's relative humidity. 

Acceptable Moisture Levels in Drywall

A drywall moisture level between 5% and 12% is acceptable based on your home's relative humidity. Drywall moisture levels can creep up under certain conditions, such as following a leak, but they should remain under 17%.

Your home's relative humidity can fluctuate based on the seasons and weather conditions. However, a relative humidity of 50% or less is considered ideal. In the winter, you may want the interior humidity to be on the lower end, around 40%, while 50% should be appropriate in the summer.

Causes of Excessive Moisture

A few factors can cause the moisture reading in your drywall to creep up. One is high indoor humidity. Areas such as your bathroom or kitchen may naturally be more humid than other parts of your home. 

In some cases, high humidity can be due to poor ventilation or an HVAC system that's not functioning as it should. A leak can also make your home more humid and can dramatically increase the moisture content in your drywall.

Signs of Too Much Moisture

You may be able to visually tell if there's too much moisture in your home and drywall. One obvious sign is mold in your house, which you may be able to smell or see. You can also test for mold to confirm its presence.

If the drywall is crumbly or discolored, it's likely that it's been exposed to high moisture levels at some point. Drywall that's been affected by water damage rather than mold may have peeling or bubbling paint.

Pro Tip

If you can smell the odor and you can’t see it, usually that is a sign of something more serious. Mold can hide behind your walls and floors and will require a professional mold remediation company to run indoor air quality tests.

Marshall Schmitz

Owner, American Quality Restoration and Mold Remediation

Maintaining Appropriate Moisture Levels

testing walls for moisture levels
Photo: Valmedia/ Adobe Stock

The trick to maintaining acceptable moisture levels in your drywall is maintaining appropriate moisture levels in your home overall. You can lower the humidity in your home by:

  • Running a dehumidifier

  • Taking cooler showers

  • Using an exhaust fan in the bathroom or kitchen

  • Improving ventilation in your attic

  • Using the air conditioning in the summer

Taking Care of Drywall

If your drywall consistently has a high moisture reading, you may need to replace it or repair the section that is water-damaged. If mold growth has occurred, removing the mold from the drywall may be the best option. 

If you're concerned about mold growth, consider hiring a local professional mold inspector to examine the drywall and recommend next steps.

Frequently Asked Questions

The best way to measure moisture levels in drywall is with a moisture meter. Moisture meters feature small probes that you insert into drywall (similar to pushing a pin into the wall). Ideally, you'll take moisture readings at several locations on the wall to get a general idea of the moisture level.

The cost for mold remediation typically ranges from $1,125 to $3,350, with a national average of around $2,400. The final price depends on various factors, including the location and square footage of the affected area, the type of mold, and local labor costs.

Additional factors that influence the total cost include:

  • Extent of Damage: The overall price can increase significantly if extensive repairs are needed after mold removal, such as replacing large sections of drywall. Removing mold from a small area of drywall might cost between $300 and $825, but full wall replacement is more expensive.

  • Health Risks: The cost is also justified by the health risks associated with toxic mold, which can cause respiratory distress, act as carcinogens, or even damage the nervous system.

  • Comprehensive Service: Remediation involves not only removing the mold but also addressing the moisture issues that caused it to prevent future growth.

  • Testing and Air Quality: The need for safety testing and measures to improve indoor air quality can also add to the cost.

For an accurate estimate, it is best to consult a mold removal specialist who can assess the specifics of your situation.

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