Mike Lamb Posted June 16, 2016 Report Share Posted June 16, 2016 I was unable to reach the top of this roof with my ladder so I took a blind video over the edge with my camera on a tripod extension. I'm a little confused at all the darkness at the modified bitumen seams. I think it had rained a little bit the previous evening. Click to Enlarge 741.87 KB Quote Link to comment Share on other sites More sharing options...
Mike Lamb Posted June 16, 2016 Author Report Share Posted June 16, 2016 Is this caused by heat from the torch? I have not seen this so pronounced. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted June 16, 2016 Report Share Posted June 16, 2016 It doesn't really look like excessive bleed from overheating. I suspect that this is a cold-adhesive application. They spread the adhesive way beyond the lap. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted June 17, 2016 Report Share Posted June 17, 2016 It doesn't look like bleed at all. It's just heat from the torch. After a few good rainstorms wash away the dry powdery stuff from the surface, the difference in color will diminish. Quote Link to comment Share on other sites More sharing options...
kurt Posted June 17, 2016 Report Share Posted June 17, 2016 It's not bleed. Agreement all around on that one. It's not heat from the torch either. It's the tar from the hot mop. It's not a cold applied application. It's SBS; it can go down cold with adhesive or laid into hot mopped asphalt. SBS mod bit, when laid into a hot asphalt and a base sheet, has seams looking like this. Google "SBS modified bitumen images". You'll get a few looking just like this. Also, the powdery white stuff doesn't wash off. It's SBS. It will subside slightly, but it doesn't go away. At least, it doesn't go away for a very long time. Following image screen grabbed from googling SBS images..... Click to Enlarge 726.08?KB Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted September 9, 2016 Report Share Posted September 9, 2016 It's heat from the torch. Here's one that I saw yesterday. It was just torched down the day before and, despite the rain at the time of the inspection, the white powdery stuff had not yet worn off - but it will very soon. I could rub it off with a single swipe of my finger. Click to Enlarge 49.99 KB Click to Enlarge 44.1 KB Quote Link to comment Share on other sites More sharing options...
kurt Posted September 10, 2016 Report Share Posted September 10, 2016 Can't you see the difference between your pic and the OP? OP field looks like SBS in tar and the walls (which no one mops cuz you can't) is over torched. Yours looks like over torched. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted September 10, 2016 Report Share Posted September 10, 2016 Can't you see the difference between your pic and the OP? OP field looks like SBS in tar and the walls (which no one mops cuz you can't) is over torched. Yours looks like over torched. I can't believe that we're both talking about the same OP picture. The whole thing is torched, not just the parapets. Quote Link to comment Share on other sites More sharing options...
kurt Posted September 10, 2016 Report Share Posted September 10, 2016 Maybe. If it is, someone was surprisingly consistent in their overtorching ****up. Look at the difference between the overtorch on the parapets and what you're alleging is the overtorch on the field. Two entirely different patterns. The OP has nice relatively even lines of darkness, exactly like a mop job. The parapets have that blasted look, especially a the kant where it turns up the wall. I'd have to touch it and see it to know for sure, and until someone does, this is all conjecture. We've got thousands of these, maybe tens of thousands, all over Chicago. They don't do it anymore, but it was standard practice for years. Mopped SBS, white powdery stuff that stays powdery for a long time, etc. exposed tar turns a different color.....they're everywhere. They look like the OP. Nice even lines of overmop. Quote Link to comment Share on other sites More sharing options...
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