RE: question about lead on May 23 2010

Lead was oridgonaly introduced to the roofing trade around the mid 1950's. All we had to work with then was "rag felt",(because it actually had chopped rag in it for strenth),and asbestos felts.when it came time to install the clamp ring on the drain it would bust the felts. So they started installing a sheet of lead ON TOP OF THE FINISHED FELT to reinforce the felt,the the lead was striped in and the roof was graveled. With the new material we have today, all you need is to bull& membrane the drain bowel before you install the base sheet. This will stop any moisture from backing up under the clamp ring and entering the building. If you have to split the material to make it fit the sump, then bull & membrane that also before installing the clamp ring. Lead is a very useless spec anymore.

Roofer,

I have to disagree....bull and rag are a short term approach to long term issue when considering BUR or mod bit roof applications. You have not taken into account the fact that plumbing vent pipes and internal roof drains are secured structurally as they run down through the building. There are thermal movement cycling dynamics in the deck that occur and that movement does not necessarily occur the same with plumbing and piping that penetrate the structural deck. Bull and rag simply can not hold up and the usage of lead was determined long ago to be the best long term solution....Industry Standard details are developed for a reason, they work. Why risk problems or reputation in the hopes of saving a few dollars.