Where to Put Flashing on a Sloped Shed Roof

Intersections

• Flashing should be installed wherever two roof lines meet. A shed roof connecting to the wall or another roof of a house, for instance, needs flashing where it joins the house or roof. This flashing typically is metal bent at a 90-degree angle to fasten to both the shed roof and the house wall or roof -- and then be covered with shingles or other roofing material.

Edges

• A stand-alone shed roof, a single-slope roof on a shed or other outbuilding, needs flashing at the ends and edges. This is called drip-edge flashing. It's installed on the wood decking before shingles are added. Typically, metal drip-edge flashing is installed under roofing paper on the angled sides and over roofing paper on the top and bottom edges. Drip-edge usually is nailed in place, often with a bead of roofing cement under it as an extra barrier.

Openings

• Metal flashing also is required around any openings in a shed roof, like chimney pipes or vents. These openings use special flashing that goes around the pipe or vent and onto the roof deck. It's usually nailed in place, then further secured with roofing cement or caulk to prevent water from penetrating at the bottom of the flashing. Any skylights also require flashing around them.

Metal Roofing

• Edge or top flashing also is needed on metal shed roofs. This will vary with the type of metal roof, corrugated panels or standing seam. Corrugated top and bottom flashing typically is made to conform to the ridges and valleys of the corrugated panel to seal the edges against water penetration. Standing-seam flashing is similar, with wider flat areas and vertical seams that overlap the edges to keep out water.