Mold Behind Drywall
Mold behind drywall is the category that most often needs professional detection, because by definition you cannot see it. Paper-faced gypsum is an ideal food source, so once water reaches the back of a wall, growth can be extensive while the visible surface looks perfect.
Signs to look for
- A musty smell with no visible source
- Staining, bubbling or a wavy surface on the wall
- Drywall that feels soft or cool to the touch
- Nail pops or seams opening up
- Symptoms in one specific room
What usually causes it
- Supply or drain leaks inside the wall cavity
- Window and door flashing failures
- Roof leaks tracking down inside walls
- Condensation inside exterior wall cavities
- Past flooding where drywall was never removed
Removing the growth without eliminating the water source simply resets the clock. Every report we write identifies the moisture source, because that is the finding that determines what it actually costs you to fix.
How we investigate it
Locate the moisture
Thermal imaging and moisture meters map the full extent of wet material, including behind finishes.
Establish the source
Groundwater, plumbing, condensation and ventilation failures all look similar at the surface and need completely different fixes.
Sample if it changes the plan
Air sampling with an outdoor control where growth is hidden; surface sampling where it is visible.
Document and hand off
A written report you can hand to a contractor, an insurer or a landlord — and independent clearance testing afterwards.
Related
Common questions
What causes mold behind drywall?
Supply or drain leaks inside the wall cavity; Window and door flashing failures; Roof leaks tracking down inside walls.
How do I know if I have mold behind drywall?
A musty smell with no visible source; Staining, bubbling or a wavy surface on the wall; Drywall that feels soft or cool to the touch.
Can I clean it myself?
Under roughly ten square feet with a known, corrected water source, most homeowners can clean it safely with gloves, an N95 and good ventilation. Above that, or where HVAC is involved, where the water was contaminated, or where someone in the household is immunocompromised, containment matters because disturbing growth spreads it through the building.
Will it come back after cleaning?
Yes, if the water source is still there. This is the single most common reason people call us twice. Cleaning removes what has grown; only correcting the moisture stops it regrowing.
Do I need a lab test for this?
Not always. If growth is visible and the cause is obvious, a laboratory result rarely changes what you should do. Testing earns its cost when the source is hidden, when documentation is needed, or when you want to verify a remediation job.
Get a straight answer about your building
We test, document and verify. We never sell remediation, so we have no reason to find a problem you do not have.