The spot where a steep-slope roof dies into a low-slope roof is vulnerable to leaks and ice dams. Even in areas that don’t see huge amount of snow, this transition area should be detailed carefully to prevent problems.

As Doug Horgan explains, protecting this area calls for the right combination of materials, beginning with a layer of fully-adhered EPDM with a total vertical rise on the upper roof of between 18 and 24 inches, plus aluminum counterflashing and a continuous bead of waterblock. One key is being careful not to mix incompatible materials.

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