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Leaky Roof Issues

Fortunately, roof leaks are fairly rare.  In some areas of the country, such as the Pacific Northwest, mold growth due to condensation is far more common.

Ceiling Water Stains from Roof Leak

What does attic mold growth from a roof leak typically look like?

Roof leaks cause two types of mold growth; systemic or limited growth.  Systemic growth occurs when the roof leak causes enough moisture buildup in the attic to cause mold growth throughout the entire area.  In this case, the moisture buildup is indirect (the roof leak only affects a small area, but the dampness in the air causes condensation throughout.)

Mold Caused by Roof Leak

Limited growth occurs when an attic has sufficient ventilation to exhaust the additional moisture caused by the roof leak.  In these cases, the mold remediation efforts can focus solely on the area surrounding the leak.

Roof Leak Mold


How are attic mold problems due to roof leaks properly addressed?

  • First, the roof leak itself must be remedied. Typically this aspect is performed by a roofing contractor rather than a mold remediation contractor. Most mold professionals are not licensed to perform roof repair.
  • Second, the current mold growth is killed with a fungicide.
  • Third, the attic is dried out, either using natural air flow or mechanical heating and dehumidification.
  • Fourth, the residual mold staining is treated with an encapsulant.

Roof leak damage in closet

Roof leak damage on ceiling

Roof leak caused by roof anchor

Roof is leaking

Roof leaks can affect the integrity of the ceiling itself.

Severe damage from leaky roof

If left unaddressed, damage from a roof leak can be quite severe.

Project Report > Mold Inspection for a Home with a Roof Leak

Work Order #: 202035

Reason for inspection:

  • City code enforcement has required assessment and remediation plan for mold growth prior to the commencement of remodeling.
  • Water damage and mold growth was noted in several areas throughout the home.
  • Indoor air quality testing revealed high levels of mold spores in the home.

Mold Caused by Roof Leak

Summary of concerns:

  • Water damage and mold growth was noted in several areas throughout the home.
  • Indoor air quality testing revealed high levels of mold spores in the home



  • Increased moisture content in cabinetry below sink.
  • Mold growth noted in cabinetry below kitchen sink.

Water Damage on Ceiling from Roof Leak

Rec Room:


  • Heavy water damage noted in sheetrock ceiling.
  • Increased moisture content in ceiling sheetrock
  • Increased moisture content noted in carpeting at NW corner
  • Increased moisture content noted in sheetrock walls at NW corner,

Dining room:

Mold under Sink on Drywall


  • Visible mold growth observed on sheetrock at exterior wall.

Bathroom 1:


  • Heavy surfaced growth noted on ceiling
  • Increased moisture content noted in bottom 12” of sheetrock throughout.
  • Increased moisture in tile around toilet
  • Low quality exhaust fan in this area.

Mold on Bathroom Ceiling

Master Bedroom:


  • Heavy damage noted to ceiling paneling, likely secondary to poor roof venting or roof leakage.
  • Obvious roof leakage into the closet.
  • Condensation based damage noted around windows.

Bathroom 2:


  • Stained vinyl flooring.
  • Missing panel to shower door.
  • Poor bathroom exhaust fan.
  • Heavy mold growth on sheetrock under vanity, likely secondary to leakage from the sink.



  • Evidence water damage bottom 12” walls
  • Old vinyl flooring in place.
  • Furnace located in this area.
  • Washing appliance hookups located in this area.

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Should I be concerned about mold growth from this roof leak?

Staining on ceiling due to roof leak.

The discoloration on ceiling is primarily due to staining rather than mold growth.  Mold growth may be present on the top side of the sheet rock (in the attic).  However, the growth is likely minor and due to the stack effect, it would not impact the indoor air quality.  Based on the photo, removal of the ceiling is not necessary.  Paint with a stain blocking primer (oil based works best) and repaint.




Recently in Florida in mobile home for a month. Toward the end of the stay black hairy mold started growing out of water stained ceilings. I got sick after I came home with asthmatic bronchitis. Do you think the black hairy mold was the cause of my illness? I don’t have a pic and can’t take one since I’m back home. Thank you.

Exposure to mold is a common trigger for asthma. While it is not possible to absolutely prove this was the cause in your specific case, it is reasonable to conclude the exposure exacerbated or created your symptoms (proof would require an air sample collected inside the home).