Closed cut valley fully replaced with new metal valley flashing.
Exposed valley roof.
When you leave the edges of your shingles exposed instead of covering and overlapping them as you would in a closed system you risk water penetrating up underneath the shingles especially during heavy rainstorms or.
Our roof valley photo above left shows roll roofing used as the exposed valley flashing for an open roof valley an accepted practice.
If you like exposed metal especially if you use copper you may want to pick open.
Shingle the other side of the valley the same way.
Entire width of new metal flashing properly extends over fascia at bottom of roof.
On the other hand an open valley roof has exposed metal that can add a unique touch to your home.
The metal is usually pre painted to best complement the shingles color blend.
If you prefer a concealed valley lining and want your roof to blend together choose the closed valley.
Fasteners placed in the exposed center area.
Proponents of the closed variety.
It is important to remember that a closed valley conceals the valley lining and allows the planes of the roof to blend together.
Roof one side of the valley running the shingles across it.
For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.
And while some homeowners may prefer the aesthetics of a closed valley the heavier and thicker the shingle the less likely it is to lie flat across a joint.
Roof mastic applied along sides of valley flashing.
How to choose a roof valley style if you cannot decide which style would suit your roof better it s helpful to understand the differences between the main valley types to gain a better understanding of their functionality.
Avoid the following common errors.
Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.
Stop nailing 6 inches from the center.
Open valleys on the other hand leave the metal exposed which may be more pleasing to the eye especially if copper is used as the valley lining.
A closed valley will blend with the rest of your roof and they can be less expensive than an open valley.
Especially if you have a significant number of valleys eliminating the metal lining will reduce the cost.
As for cost closed cut valleys are the way to go.
Ice barrier underlayment installed in roof valley.
However a closed roof might have a challenging installation especially if your home has sharp angles.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
That flashing is left exposed so the roof has visible lines of metal running down the valley.
In our opinion df while roll roofing or peel and stick ice and water shield membrane work well as roof valley underlayment using roll roofing as the final surface in an open roof valley is not as durable.
