Slate Roof Valley Flashing

Brent ulisky of ulisky slate demonstrates flashing a closed valley at the 2015 slate roofing contractors association 10th anniversary conference near grove.

Slate roof valley flashing.

Roof valley flashing material options there is a lot of misinformation and confusion out there when it comes to properly waterproofing roof valleys. Lap successive sheets of metal flashing a minimum of 12 inches and seal laps. Next step is to install your starter course slate. Apply an approximately 3 inch width of asphalt roofing cement along the sides of flashing and embed shingles in mastic.

For roof pitches less then 6 per foot the flashing extends at least 12. Intersecting roofs using a closed valley must have the same slopes so that the shingle butts line up at the valley intersection. Structural issues inadequate construction improper roofing methods and material deterioration. Then install a non corrosive metal valley flashing of 24 minimum width.

The installer fabricates simple clips or valley flashing cleats whose bent edge interlocks with the folded over or hemmed edges of the metal roof valley flashing to secure the valley to the roof deck. Common causes of roof valley leaks. For example in metal roofing systems valleys are commonly fabricated with hems but can also be fabricated without them in which case they could still be used for metal roofing or any other type of roofing. Whether for slate shingle or metal roofing valley flashing adds detail and helps to direct water.

There are many factors that can contribute towards a failure of a roof valley flashing. Valley flashing is used for flashing where roof valleys are constructed. The lower edge of the flashing should be held 1 2 short of the butt line of the slate tile or shingle in the succeeding course. These items can be fabricated in many different profiles.

Diagonal cuts can be made to the top corner of these slates in the valley so the pointy edge does not damage the metal. Install an underlayment centered in the roof valley. Using clips permits movement in the valley as temperatures change. For roof pitches of 6 or more per foot the flashing extends at least 9 under the roof covering on each side.

The cleats accommodate thermal movement in the valley flashing to prevent stress cracks. Missing ice water shield. As this weak spot on your roof directs large amounts of water it is a common source for leaks. The first step to installing an open valley is to cleat your valley metal in.