How much moisture in drywall is acceptable?

Author: Mr. Lisandro Abernathy DDS  |  Last update: Tuesday, October 28, 2025

The real question is not whether your drywall is dry but whether the moisture level it contains is safe and appropriate. An acceptable level of moisture content is between 5% and 12%. Even a higher level may not spell disaster if not confined to a small area.

What is a safe moisture level in drywall?

A drywall service will know that homes have moisture levels of 50% and lower and this varies from home to home. An appropriate level of moisture for drywall is between 5-12%.

What is a bad moisture reading for walls?

A moisture meter reading above 16% is generally considered damp, with higher readings posing greater risks. For plaster walls, readings over 20% may indicate significant water ingress, often caused by leaking pipes or external wall defects.

What is an acceptable reading on a moisture meter?

You should be aware that a moisture reading of 0-15% is quite normal and gives no cause for concern. However, moisture readings in excess of 15% indicate the need for further inspection. Levels between 25-30% indicate that there may be water ingress, meaning that remedial work could be required.

What are normal moisture levels in bathroom walls?

The walls and flooring in every bathroom that is being used on a regular basis will have some degree of moisture present. Normal bathroom walls and floors have a general moisture reading of around 3.5 to 5.5. Anything under 3.5 is great and anything above around 7.0 should be investigated and monitored.

How to Use a Moisture Meter | Ask This Old House

How wet is too wet for drywall?

The general rule is that any moisture reading over 16% is considered damp and needs attention. If your reading is over 20%, you may need to replace the drywall entirely. The walls in your home with healthy humidity levels should have a moisture reading between 12 to 15%.

How do you get moisture off bathroom walls?

While you will never stop condensation forming completely, you can greatly reduce the impact it has.
  1. Open a window while you shower. ...
  2. Wipe down wet surfaces after use. ...
  3. Turn the shower cold once you're finished. ...
  4. Use a mould-prevention paint. ...
  5. Decorate with dehumidifying plants. ...
  6. Install a powerful extraction fan.

What moisture reading indicates mold?

Moisture meters help detect moisture spots with possible mold growth. If your MC reading in wood is more than 20%, you may want to check these areas for mold growth. When the MC is above 20%, this is possibly where mold growth can start to happen. Humans have reason to attach negative connotations to mold.

How accurate are moisture meters for walls?

A quality meter will be highly accurate and have a measurement range of 6 to 30%. It will also provide a way for the user to verify calibration. Cheap moisture meters might promise accuracy, but they'll lack the evidence for it. They won't have any studies to prove their accuracy.

How to detect moisture behind drywall?

Moisture within and behind walls can be detected with a pinless moisture meter. A non-destructive moisture meter can accurately locate and measure elevated moisture levels without the need to break the wall's surface material.

Can moisture in walls be fixed?

Exterior waterproofing coats can be applied to the exterior walls to stop water from penetrating the walls. The barrier that a waterproof coat will create will insulate walls and keep out rain and moisture, keeping walls from becoming damp. You can treat dampness in the interior walls by waterproofing the roof.

How do I know if my room has too much moisture?

The most common signs of structural damage due to high humidity include chipping paint or wood rot on window frames, wet walls resulting from condensation build-up, cracking floors, and plaster walls due to expansion and contraction caused by fluctuating temperatures between day and night as well as summer and winter ...

How do you reduce moisture in drywall?

The best way to dry wet drywall is to dry it from the inside out. This can be done by using a fan or a dehumidifier. Use a moisture meter to check the moisture levels. Once you have started drying the drywall, checking the moisture levels with a moisture meter is important.

What moisture meter do home inspectors use?

Pinless moisture meters are definitely the way to go for home inspectors. Not only is their technology highly advanced and accurate, but they are extremely fast and easy to use. Given all of these great features, pinless moisture meters might even be a great choice for homeowners.

What moisture level for studs?

The industry standard for acceptable moisture content (MC) in wood framing varies depending on the location. But typically, the number is somewhere between 9 and 14% MC.

What is a normal moisture reading for drywall?

Readings of 5 to 12% are considered normal, and up to 17% is considered acceptable.

What moisture reading is too high?

A 20% damp level in a house is generally considered high and could indicate a moisture problem. Excess damp can lead to various issues, such as mould growth, structural damage, and potential health concerns.

Do home inspectors check for moisture in walls?

During a home moisture inspection, these spots are standard places to test: Walls and ceilings. Concrete basement floors. Attics.

What tool is used to detect mold in walls?

Moisture meters not only help identify the reasons for existing mold growth but also aid in preventing conditions that could lead to mold in the future.

Can I use a wood moisture meter on drywall?

Your moisture meter will now operate on a relative measurement scale (0-100), suitable for measuring non-solid wood or non-wood-based materials, including drywall.

What is an unsafe level of mold?

A concentration of mold spores above 500 sp/m3 is considered high. Therefore, if your report comes up with high concentrations of mold, it will likely advise you to remediate the problem. However, it is important to note that even low concentrations of mold spores can cause health problems in some people.

How do you fix high moisture in walls?

Increase air circulation by using fans and by moving furniture from wall corners to promote air and heat circulation. Be sure that your house has a source of fresh air and can expel excessive moisture from the home.

What is the best moisture absorber for the bathroom?

Moisture is well absorbed by black tea, baking soda and silica gel. These are commonly available products which can be poured into a moisture-permeable fabric pouch and then placed in the bathroom. To give it some fragrance, add in dry flowers, ground coffee or orange slices.

Why do my bathroom walls look like they are sweating?

Those high humidity levels are particularly problematic when the moisture can't escape through windows, doors and other forms of ventilation. That's when condensation comes into play, with the moisture condensing from a gas into a liquid on the nearest cold surface – which in many cases is your bathroom walls.

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