Garage rool roof

I see this quite often on asphalt rool roofs.

What causes the material to raise up. Also what is the proper terminology for this. Also why did they install boards along the edge?


Moisture and improper application of the rolled roof asphalt.
It is commonly referred to as Blistering of the Rolled Roofing.

As far as the edge wood…hmm…Improper Amature installation…and expedited application for Rotted Wood and channeled leaks?

The exposed fasteners should be covered with mastic to prevent moisture intrusion. (cover the nails with tar to prevent leaks).

It looks like, and I am just judging by the picture, that it is 90lb. Underlayment that was improperly installed as a final roof covering.

If it is 90 lb. it is not rated for sunlight and will deteriorate in a few years.
The wrinkles are there because it was not rolled out properly and it wasnt attached properly.

If you are going to cover a flat roof with a rolled roofing product, center cap for instance, it is usually hot-mopped in. There should be no fasteners and the rows should overlap each other.

I would have recommended replacement of the roof.

Agree with all.

All someone has to do is walk on top of one of tose wrinkles and oops…You’ve got a roof leak.

With this installation…Recommend replacement soon.

Seems from the picture that this roof is too flat for roll roofing.

Maybe I am wrong, but it dose not look proper.

Blisters on an almost flat roof may be caused by heat and sun, but often signify moisture under the surface. The chances are good that water has penetrated the roof membrane through a nearby hole or flashing. If there are several blisters or the blisters are quite large, consider calling a roofing contractor to handle the work.

My reccommendation at this phase would be contact a reputable Roofing Contractor to asses the repairs as required.

Marcel :slight_smile: :slight_smile:

I think what you might be looking at there is an amature installation of 1 ply 180g SBS granular sheet.
It looks like the heat process used at the under side did not heat the granular sheet adhesive enough to bond to the base sheet.
Hopefully there was a base sheet such as 1 ply 95 SBS & some thing such as 180g SBS base sheet.
The perimeter boarding or facia’s also need covering and protection.


That is excellent, and that quite effectively illustrates two different styles of report writing:

My competition: “The exposed fasteners should be covered with mastic to prevent moisture intrusion.”

Me: “Cover the nails with tar to prevent leaks.”


That’s what I call them, too.

The wrinkles are caused from the roof material not being stretched properly before they nailed it.

Example: Roll the roofing material out over the sheathing on a cold morning, pull it as tight as you can, when the sun hits it expansion occurs, wrinkles forever.

Example: Roll the material out over the sheathing and do not stretch it, just nail it, wrinkles forever.

Best installation method: Roll the material out over the roof sheathing, let the sun hit it for a few hours until it becomes limp (pliable). Apply an asphalt roof emulsion over and under the tar paper before installing the roof covering, stretch the asphalt roll material across the roof and fasten it, no wrinkles.

Obviously an amateur installed it.

:mrgreen: or you could do it in true home owner fasion and rent a carpet kicker:mrgreen: