Robert Jones Posted February 12, 2013 Report Share Posted February 12, 2013 Flat roof on a small commercial building. Can't say that I have ever seen the "bubbling" effect that was visible on this roof. Is there a specific cause for this condition? Click to Enlarge 39.36 KB Click to Enlarge 31.49 KB Quote Link to comment Share on other sites More sharing options...
Rocon Posted February 12, 2013 Report Share Posted February 12, 2013 Was it on a W-deck? Is there a polyiso insulation layer below the membrane? Does the blistering only occur at the edges of the ponding water? How long does the water pond on the roof or when was your last rain? Typically one of two things is going on: 1. The coating was in direct sunlight when it was applied. This causes the surface to skin off early. The trapped volatiles work their way out of the material and cause the blistering. 2. There is water trapped in the roof assembly. This usually causes a larger blister so it is less likely to manifest like the photos you have. Quote Link to comment Share on other sites More sharing options...
Robert Jones Posted February 12, 2013 Author Report Share Posted February 12, 2013 Not sure about the insulation below the membrane. We haven't had a ton of rain lately and there was quite a bit of water ponding on one side of the roof. That would be the side with the blocked drains, so that was self explanatory. The blisters were located in different areas on the roof. Not just at the edge of the ponding water. Quote Link to comment Share on other sites More sharing options...
Marc Posted February 12, 2013 Report Share Posted February 12, 2013 One scenario...when mopping has just been completed, excessive moisture trapped below reaches the boiling point after the asphalt has cooled enough to form a solid but still flexible film on the surface, producing the blisters. Marc Quote Link to comment Share on other sites More sharing options...
John Kogel Posted February 12, 2013 Report Share Posted February 12, 2013 Sloppy workmanship would pretty well cover it, IMO. We normally expect them to put a layer of gravel on there to protect the tar from the elements and prevent that type of thing. Quote Link to comment Share on other sites More sharing options...
hausdok Posted February 12, 2013 Report Share Posted February 12, 2013 Yep, Might be incompatible materials. The moisture scenario works too but not because of boiling - because bacteria trapped in the moisture multiplies and gives off gas that expands and forces the stuff to stretch until it fractures. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
Rob Amaral Posted February 12, 2013 Report Share Posted February 12, 2013 That looks like trapped moisture to me.. Quote Link to comment Share on other sites More sharing options...
kurt Posted February 12, 2013 Report Share Posted February 12, 2013 Moisture in the bitumen. Quote Link to comment Share on other sites More sharing options...
Scottpat Posted February 12, 2013 Report Share Posted February 12, 2013 I agree, moisture in the bitumen. Quote Link to comment Share on other sites More sharing options...
Les Posted February 12, 2013 Report Share Posted February 12, 2013 it is moisture. really common here in Mich. Quote Link to comment Share on other sites More sharing options...
Rob Amaral Posted February 12, 2013 Report Share Posted February 12, 2013 Moisture in the bitumen.. a 'real pain in the ass'.. Hey man, you have moisture in your bitumen.. haven't you seen a doctor..? Quote Link to comment Share on other sites More sharing options...
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