Mold Assessment Helps Home Seller By Revealing Roof Leak

Healthy Home’s, Mold Limited Screening Service helped a client who was trying to sell his home determine that a roof leak was responsible for a mysterious stain that was causing concern for potential home buyers. Because of this, our client was able to avoid creating a haven for excessive mold growth in his home – a situation which would have certainly deterred any potential home buyers in the future.

Our client, Charles, had put his two-story home up for sale. He contacted us with concerns about potential mold growth in his home’s attic area. He told us that a prospective buyer’s home inspector had identified suspicious staining along the underside of his home’s roof sheathing in the attic space above the upper-level hallway.

Concerned about the potential for elevated mold growth, Charles wanted us to perform a limited visual mold assessment in combination with surface sampling services in the accessible areas of concern of his home’s roof and attic.

Visual Assessment

We determined a convenient time for Charles and visited his house to perform the visual assessment. We looked for mold growth in the attic area on the underside of the roof sheathing. We searched for evidence of water intrusion such as structural wood decay or warping, peeling paint or cracks or splits in the area. We also looked for any evidence of other moisture-related issues such as high humidity or condensation in the same area.

This visual inspection revealed no evidence of mold growth. We did find a small area of staining from water intrusion along the edge of the underside of the roof sheathing at the northeast end of the attic space above the upper level. The attic space was accessible from the attic hatch in the upper-level hallway. We determined that the most likely cause of the staining was a roof leak.

Wanting to determine how far the moisture had spread, we used a moisture meter to determine the moisture content of materials likely affected by the leak. The moisture meter has two thin probes that are inserted directly into the material to be tested. These moisture readings are then compared to similar building materials in non-affected areas as well as industry standard moisture levels.

We also used an infrared camera to view a visual spectrum of thermal energy. Temperature and relative humidity readings measured from the residence’s interior were within acceptable industry standard ranges. We found elevated moisture readings in the same area as the staining, but we found no other evidence of water intrusions or moisture-related issues.

Mold Testing

Mold testing allows us to discover whether mold spores undetectable by the naked eye were growing in the area. We collected a surface sample of the suspect staining along the edge of the underside of the roof sheathing. The sample was taken in a thorough effort to determine whether any type of mold growth was present in the area. Test results from surface sampling did not identify any elevated presence of mold growth at the sample location.


Thankfully, this turned out to be a situation where early detection could result in repairs that would prevent creating conditions that would foster mold growth. We were called in and got to the root of the issue before too much damage could occur. Neither our visual assessment nor the surface sampling revealed any evidence of excessive mold growth.

Our experience helped us determine that the most likely cause of the staining on the underside of the roof sheathing was a leak in the roof. We recommended that Charles promptly address the roof leak to stop any further water intrusion. He could then mitigate any moisture-related damage and prevent potential mold growth – all of which would be necessary for a happy, healthy, and successful home sale!

Dan Rouse