The short answer
Visual Clues on the Wallpaper
Check the wallpaper surface for dark spots, stains, or a greenish or black tinge. These can appear as blotches that spread over time. Bubbling or wrinkling often means moisture is trapped underneath, which creates the right conditions for mold.
Look at seams and edges where wallpaper meets trim or corners. Peeling or lifting edges are common entry points for moisture. If you see any discoloration along these lines, mold may be growing behind the paper, even if the front looks mostly clean.
Smell and Touch Tests
A musty, earthy smell is a strong clue that mold is present, even when you cannot see it. Put your nose close to the wall and breathe in. If the odor is noticeable, moisture and mold are likely behind the wallpaper.
Press gently on the wallpaper with your hand. Soft or damp areas indicate water damage. A cool spot on the wall can also signal moisture. These signs do not confirm mold, but they tell you where to look more closely.
Using a Moisture Meter
A moisture meter is a simple tool that measures dampness in building materials. You can buy one at a hardware store or borrow one from a friend. Hold the pins against the wallpaper and read the number. High readings mean moisture is present, and mold can grow in such conditions.
Moisture meters are not foolproof, but they help you find problem areas without tearing up the wallpaper. If you are unsure how to use one, the pros often perform moisture mapping to locate hidden moisture. This can confirm whether mold is likely behind your walls.
Peeling Back a Corner
If you have strong signs of mold, peel back a corner of the wallpaper carefully. Use a putty knife or your fingers to lift the edge. Look for black, green, or white fuzzy growth on the back of the paper or the drywall underneath.
Wear gloves and a mask to avoid breathing in spores. If you see mold, do not scrub it while it is dry, as that can release spores into the air. Dampen the area lightly before handling. For extensive growth, a mold professional can assess the situation safely.
When to Bring in the Pros
If you find mold behind wallpaper, the affected area may need professional attention. Mold can spread into wall cavities and affect indoor air quality. Local water damage pros can help with water damage inspection and structural drying to prevent further growth.
- Dark stains or speckles on the wallpaper surface
- Bubbling, peeling, or wrinkling wallpaper
- Musty or earthy odor near the wall
- Soft or damp spots when you press the wall
- High readings on a moisture meter
- Visible mold on the back of peeled wallpaper
Talk to someone now
Phones are answered 24/7 for Caldwell and nearby communities.
Call Now (208) 729-2441Frequently asked questions
Can I test for mold myself?
You can do a simple swab test with a cotton pad and send it to a lab, but results take time. A more practical first step is using a moisture meter and looking for visual clues. For accurate identification, a mold professional can take samples.
What if I don't see mold but smell it?
A musty smell often means mold is growing in a hidden spot, such as behind wallpaper or inside a wall. Use a moisture meter to find damp areas. If you cannot locate the source, the pros can help with leak detection and moisture mapping.
Is mold behind wallpaper dangerous?
Mold can cause respiratory irritation, allergies, and other health issues, especially for sensitive people. If you feel unwell, see a doctor. For large areas, have a mold professional assess and remove the mold safely. Keep the area dry to prevent further growth.