Thread: Underlayment identification

Is this a approved underlayment for a comp shingles?

The material in unadhered and very flexible, it feels (and looks on the underside) similar to ordinary black 4mil plastic sheet.

At other locatons there was no underlayment at all, there were no drip edges at any location I checked, and the roof was a low-bidder job in other ways (including retaining existing shingles in areas where it would have been little additional effort to replace them). So it would not have surprised me to discover that the "underlayment" is just 4mil plastic, however the textured upper surface and white stripe suggest the material was manufactured for some specific propose. But would the plastic underside not act a a vapor retarder to trap moisture against the sheathing?

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Also, given that in other areas there are two layers of sheathing visible at the eave I'm wondering if cut gutter hangers above some portion of the roof just indicate a gutter replacement, or if the lower portion of the shingles may have been replaced for some reason - though the shingles across the entire field of these roof sections appear identical.

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No one can identify this stuff ???

Looks like some kind of peel-and-stick to me.

Might not even be underlayment (meaning not under everything), it might just have been installed up that rake.

There are peel-and-stick tapes made to tape up the seams between the roof sheathing, to prevent water intrusion if the roof covering is lost in a storm, could be that stuff, only it was applied up the rake?

Double sheathing.

What does in look like in the attic. Is there skip sheathing for an old shingle roof and they put full sheathing over it???

Jerry, sorry I was not more clear, that's an eave, and that stuff is not adhesive, its just smooth black plastic on the underside (you can see some curled up in the picture).

Ted, "Is there skip sheathing for an old shingle roof and they put full sheathing over it???"

Exactly: