Find the moisture level that's just right for your home
The relative humidity in your home affects the moisture level in your drywall.
When moisture levels are too high, there's a risk of mold growth and damage.
Lowering indoor humidity can help you control moisture issues.
If the moisture level in your drywall gets too high, you may need to replace it.
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.
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.
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.
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.
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.
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
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.
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.
While a moisture level between 5% and 12% is generally acceptable, consistently getting readings above 17% is a sign of extensive moisture damage. At that level, the drywall is likely to be compromised. Replacing the drywall, either in its entirety or the section with the above-acceptable moisture level, is recommended.
If high moisture levels have led to mold growth on your drywall, mold remediation may be your best bet. The average cost of mold remediation is $2,400, but the total price depends on how much you need to repair and the location. Removing mold from drywall may cost you between $300 and $825, but the overall price could be higher if you need to fully replace several walls in your home.
