In my many inspections of decks throughout the years as an estimator, I have seen many failed methods that were used in an attempt to install a drain through the floor of a deck coating. I often see drains that came from Home Depot type stores, and also see professional type drains that came from a plumbing supply house.
The drains you buy at these places are not manufactured with deck coatings terminating into them as part of their function. Because of that one flaw, the decks are doomed to fail. The picture above shows a plastic drain system with overflow. The deck guy had the right idea but executed the job with the wrong drain. The plastic deteriorated over the years, the flange is flexible and stepping on it probably damaged it too. As a result, water leaked by the flange and into the ceiling below. We removed that drain and installed copper drains with overflows on them.
The only drain systems I use are from Thunderbird Products, Inc. of El Cajon, CA. They have specific drains for decks and roofs, including tile deck systems, that allow the proper termination of the drain with the deck coating/waterproofing materials. Click the link above to see their online catalog of drains and scuppers or call them at 800-658-2473 to place your order. Tell them Bill Leys sent you their way!