Protrusion In The Roof
When laying out the field sheet and a curb (chimney, skylight, etc.) is encountered, unroll the folded membrane up to the curb while maintaining proper sheet alignment with walls, perimeter edges and other protrusions.
Measure the width and depth of the unit and transfer the corresponding dimensions onto the folded membrane. Draw an X inside the box. Cut the X mark and from one corner cut a straight line to the nearest edge of the membrane. Roll the membrane around the unit, leaving a triangle of membrane turning up all four (4) sides. Using a standard paper punch or scissors, punch or cut a round hole at every angle change of the membrane at the outside corners. (This will prevent the cut in the membrane from continuing.)
After all cuts are made and the membrane has been correctly positioned, fold the membrane back and begin bonding procedures. After the field membrane is complete, bond the triangles up the sides of the unit (chimney, skylight, etc.). Take care to bond the membrane into the angle change so that the membrane is completely adhered. Membrane should travel up the wall at least twelve inches (12") or to the top of the opening if it is less than twelve inches (12").