June 17, 2005 Roof Report
May 21, 2017Tar and Gravel Roof Leak
May 21, 2017
1. In this case we have a leak on a torch on roof that was occurring along the bottom edge. The original installer did not terminate the membrane properly. Requirements are to terminate using a drip edge flashing. This guy just let the Soprema torch on membrane hang over the edge. He thought it would drip into the gutter but instead it wicked along the underside of the membrane, saturated his plywood, flowed behind the eaves trough and dripped on the sun deck below.
2. The first requirement was to prepare the existing roof membrane to receive the new membrane I was going to install. This process is called "degranulating" and it is critical for an optimum torch- weld bond . Unfortunately some roofers skip this step as it is labor intensive.
3. We then installed the 26 gauge metal drip edge. We didn't need the 100 nails used to ensure the flashing was held in place.10 or 15 would have done that. We use this many nails to ensure the metal doesn't buckle too intensely during the torching process. That's another critical step in the process that many may omit.
4. To properly waterproof any roof, or detail on a roof, it is best to use a two step waterproofing process. In torch-on roofing we call this a two-ply. Two separate membrane layers with two separate bonds to and with the receiving substrate with each bond extending further beyond the boundaries of the first ply. In this photo we have applied the first "base" layer.We are essentially water-tight at this junction however we are not UV protected. In addition we still require a 2nd ply.
5. In this photo we are one piece away from completing the job. Notice how the granular cap sheet pieces are wider than the first base layer. This gives us two barriers/welds/seams the water has to get through before it becomes a leak.
6. Membrane termination exceeded flashing termination on the one end of the gutter.
7. And on the other end of the gutter we wrapped our drip edge metal around the corner for aesthetic purposes. Again, the membrane exceeds the coverage of the flashing.
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Location: Delta, B.C.