Torch-down roofing is a popular method for flat or low-slope roofs, where modified bitumen membranes are heated with a torch to seal layers together, creating a durable, waterproof surface. Valley leaks in torch-down roofs can happen because valleys—where two roof sections meet and direct water down—are natural weak points. Causes often include improper installation of the membrane, damage from UV exposure or foot traffic, or clogged valley areas that cause water to pool and eventually seep through small cracks or seams. A simple way to check for leaks yourself is to inspect these valleys for visible cracks, blisters, or signs of water pooling. You might also shine a flashlight from the attic during daylight to spot light coming through gaps. However, be cautious with torch-down surfaces because walking on them can cause damage if the roof is hot or brittle.
If you suspect a valley leak, calling a professional roofer is wise, especially to avoid weakening the roof or voiding any warranty by trying complicated repairs. When you reach out, ask if they will inspect the entire valley membrane and flashings, and specifically how they plan to address any sealing issues. Inquire whether they use a hot torch or cold adhesives for repairs, since improper heating can cause more damage. Also, ask about warranties on their repair work to ensure you’re protected in case leaks persist. Knowing these details helps you get a quality fix that keeps your roof watertight and extends its lifespan without costly repeat visits.