Roof Valleys and Leak Protection

It’s important to follow the best roofing practices because snow & ice will stay in the roof valleys the longest.

Traditionally, roof valleys were closed with shingles (closed valleys). In recent years this practice has been replaced with open valley installation: shingles on either side of the valley separated by metal flashing.

Although closed valleys are still occasionally used, it is no longer the preferred choice because of inferior water resistance. Valley metal moves ice, snow, and water off the roof much faster. IKO’s Blueprint for Roofing states, “For longer roof performance, open metal valleys are recommended.”

We agree and have abandoned the use of closed valleys.

How Do You Know If Your Roof Valley Metal was Properly Installed?

Like many things about your roof installation, it’s difficult to judge the quality of the installation unless you’re up on the roof.  Here are some things to check if you want to make sure:

  • Does the estimate state that the contractor is re-installing valley metal?  If not, that is the first sign that you may have future problems.
  • Does the estimate identify the underlayment that will be installed underneath the valley metal?  Proper installation of valley metal requires underlayment be installed first. The underlayment can be felt paper, rolled roofing or, for maximum protection, Ice & Water Protector.
  • Are the cut-out lines in the valley straight? A chalk line should be used to cut out a 6- to 8-inch strip through the centre of the valley.

A Done Right Roofing Extra

Manufacturers recommend that you tar underneath the shingle where it overlaps the valley. We go an extra step to ensure the absolute best performance: a valley starter strip.

Done Right Roofing installs the underlayment in the valley, then the metal flashing. Then we chalk our lines. For added protection, we install a starter-strip shingle on the chalk line on both sides of the valley, then shingle the roof surface, and finally cut out our valley centre.

This starter strip adds an extra layer of protection that is then shingled over. This is much better than just tarring underneath a few shingles and ensures you get the absolute best performance out of your roof.