Pig’s Ear?

When most of us hear the words “pig’s ear” the first thing that might come to mind is a delicious treat for a dog to chew on.  However, this term also describes a special membrane folding technique to create an end dam with membrane flashing.  So don’t feel bad if you were on a job site, heard this term, and were utterly confused about why someone brought up Fido’s chew toy.

We recently ran into this term during roof replacement projects at two schools in Springfield, MA. 

In the photo below, the silver membrane is flexible self-adhered flashing.  The membrane is folded into a single piece end dam with upturned sides and without any cutting of the membrane which could allow water penetration through otherwise water tight flashing.  This folding method is a way to create sill pan flashing at the corners of a window, door, or other wall penetration and is commonly referred to as a “Pig’s Ear” in reference to the shape that the critical fold creates.