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Over the last week the "roofing crew" has developed a new dance. Its purpose is rather mundane - tamping down seams between strips of the roof membrane to get a good seal, but its implementation can be entertaining.
We used a product called bituthene which comes in 66-foot rolls that are 36 inches wide. They require an overlap on the edges and ends as they are laid down in shingle fashion from bottom to top. Lines on the edges of the strips aided in alignment, but it took a number of strips before we found a placement method that produced the best results.
We learned that it was counter-productive to try to run a single length of the material all the way across the roof. Unless we started out precisely straight with the roof and with the previous strip, the slightest angle off caused the line to veer further as we went along. This would cause an insufficient overlap which had to be corrected with a short overlay, and this is not best since the shingle effect is lost where the overlay covers both strips. Consequently, we chose to limit each strip length to no more than about 12 feet.
We had to put the membrane down carefully to be sure we got the required overlap and to prevent creases from forming. This took a crew of three: one to hold the whole strip off the surface and let it down slowly and evenly, one to wrangle the paper backing and one to press the membrane down smoothly. Near the end of each strip the first two shared their duties as the remainder shortened.
On each side of the membrane roll there is a very narrow strip that is not covered and is very sticky, like the bottom surface. Once a strip was in place, and while the next was being cut to length, two people were free to stomp the seams. This was done using the backing paper that had been removed since one side of it does not stick to the membrane.
Weather was a factor. It rained a number of times before we were finished. Each threat of rain required us to recover the roof with our trusty billboard tarps. And after each rainfall we uncovered the roof again and found something else to work on until we were sure it was dry. Fortunately, the rainy weather also brought windy days so the drying off time was shortened. Overall it took about eight days to finish the job, though few of them were full ones.
Surprisingly, after all the miserable weather we've had the last month or so, I found myself hoping for cold weather to place the membrane since it was far less sticky when it was cold. Cloudy days were welcome.
The pictures below show the process, the "dance" and the roof covered with the membrane.
