It is important to remember that a closed valley conceals the valley lining and allows the planes of the roof to blend together.
Exposed valley roof.
Proponents of the closed variety.
Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.
Roof mastic applied along sides of valley flashing.
The metal is usually pre painted to best complement the shingles color blend.
On the other hand an open valley roof has exposed metal that can add a unique touch to your home.
Fasteners placed in the exposed center area.
If you like exposed metal especially if you use copper you may want to pick open.
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.
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.
For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.
Some homeowners do not like the look of open valleys while others feel the metal accentuates the roof s shape particularly if copper or painted flashing is used.
Shingle the other side of the valley the same way.
Especially if you have a significant number of valleys eliminating the metal lining will reduce the cost.
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.
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.
Ice barrier underlayment installed in roof valley.
Entire width of new metal flashing properly extends over fascia at bottom of roof.
Our roof valley photo above left shows roll roofing used as the exposed valley flashing for an open roof valley an accepted practice.
Avoid the following common errors.
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.
Closed cut valley fully replaced with new metal valley flashing.
Stop nailing 6 inches from the center.
However say that while the rainwater might move off of a roof faster with exposed flashing it certainly does not protect your roof as well.
Roof one side of the valley running the shingles across it.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
As for cost closed cut valleys are the way to go.
That flashing is left exposed so the roof has visible lines of metal running down the valley.
The two roof planes will stop a few inches short of this to leave the valley open with the waterproof materials exposed.
