“Light fixtures, fans, vents and skylights are almost always at the lowest position. If a home includes a leak inside the roof or if elevated appliances including HVAC units start to leak, gravity does the rest of the function and delivers the drinking water pooling into these places.” Verify online https://israelvinkj.dm-blog.com/33836992/the-fact-about-roofing-supplies-that-no-one-is-suggesting