Living with Mold Risks

How To Live With A Flat Roof


Main Problems:

Mold from Leaks

Hard to Find/Reach Mold

Severity of Mold Risk:

Cost of Recommendation:

$800-1200 /year


The Problems

Flat Roofs Often Develop Leaks, and Leaks Result in Mold

It is common for any roof to leak but flat roofs leak far more often, increasing the likelihood of having water in your home that can lead to mold growth. Water is necessary for mold growth. Since our homes are made out of mold food (e.g. – paper backed drywall, wood studs, plywood sheeting, etc.), adding water leads to mold problems. Flat roofs are more likely to have leaks due to water pooling and the flat roof having more transitions than pitched roofs (i.e. – roof to parapet or transition, roof to canales or downspouts, etc.). In addition, many flat roof homes lack access to institial space between the ceiling drywall and the roof, which makes inspection difficult. 

Mold Growth In Hidden Or Unsuspecting Areas

If water does make its way into your home due to a roof leak, it can end up in unsuspecting areas, such as behind appliances, behind drywall, in dark corners, etc. Without periodic inspections, mold could be growing right under your nose and causing health issues without evident signs of water damage or visible mold.

Mold Prevention & Recommendations

How To Live With A Flat Roof


Periodically Check for Leaks



Parapet Cracking – Check to ensure that the parapet materials are not cracked (especially if the house has a stucco exterior). If cracks do exist, fill them with a silicone, or similar sealing product.

Attic Water Staining – If possible, look at the roof decking from the attic side to determine if there is any water staining, which would indicate a roof leak.

Canale Seal – Inspect canales to assure that the seal between the roof and the canale is not splitting, that the wood is not deteriorating or splitting (if canales are made of wood).

Nice to have

Heavy Rain – Within 48 hours of a significant rain (greater than ~0.5” in an hour) perform an infra-red (IR) camera inspection on all indoor walls and ceilings. This can be done by hiring a home inspector or indoor air quality inspector to perform the IR investigation, or by buying an IR camera and DIY.

Our Recommended Infra-Red Camera

Humidity – Measure the humidity in your home to assure that it stays <60%. Amplified humidity could indicate a roof leak.

Our Recommended  Hygrometer


Reduce Blockage & Vulnerable Areas



Proper Draining – Ensure roof drains, canales, downspouts, are not plugged/blocked.

Water Pooling Ensure that water does not pool anywhere on the roof. Check the entire roof after a significant rain (greater than ~0.5″) and look for pooling.

Strongly Recommended

AC – Ensure that roof-mounted Air Conditioning (AC) units have a condensation line that drains off of the roof.

Roof Vents – Make sure that your home has roof vents and that they are not blocked.

Roof Penetrations – Minimize unncesessary roof penetrations, especially skylights.


Professionally Maintain Your Roof



Have a roofing contractor inspect the roof every 18 months or so, patching as necessary (especially around roof penetrations from exhaust vents, HVAC equipment, skylights, etc.).


Periodically Test for Mold



Every 6-12 months check your indoor air for mold growth with the Mold Check-Up. If your results show significant mold growth, that could be an indication of a roof leak.

Guides for tackling mold

Living With Mold Risks

Guides for reducing mold and maintaining cleaner
environments in situations we can’t change.

Flat Roof



Visible Mold


Indoor Plants


Evaporative Cooler