Flat Valley Roof

Just enough slope to drain water but also flat enough to be a problem if not constructed properly.

Flat valley roof. Repairing a dead valley isn t really a diy project for most homeowners. A roof valley is formed where two roof slopes meet. Most roofers that do shingles will use a heavy base paper instead of a rubber membrane. Despite this flat roof valleys should never be built.

When a valley is flat like this one in the image it is more problematic. The roof design is as essential to the proper function of a house as is the foundation plumbing or electrical design. Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks. Valley areas are prone to leak due to the lack of using proper materials.

Valleys are a prime leak area so it s important to be careful. Also different architectural styles will use the same type of roof. Valleys are typically found where gable dormer roofs meet the main roof or when a house has angled wings or additions where two roof sections in different planes meet. The open woven and closed cut methods are demonstrated.

A roofer must be careful where the nails are placed in the shingles of valley roofs. Gaf mastering the roof chapter 12 this video demonstrates the proper installation technique for installing roofing valleys. Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot. Water collects in a valley to flow off the roof.

There are two basic types of valleys. Woven closed cut and open. Because of the volume of water and lower slope along valley lines valleys are particularly vulnerable to leakage. We love the flexibility of a flat roof for certain design limitations but they have a bit of reputation for leaks and repairs.

Water like to follow the valley to the edge and flow back under the valley. Intricate roofs have many parts that incorporate several of the basic roof designs such as a gable roof sitting atop a gambrel or variations of the gable valley roof design using one or a variety of different types of roof trusses also see our very detailed diagrams showing the different parts of a roof truss. Valleys are created where two roof slopes meet. These leaks can be caused by poor roofing practices or just simply by the age of the shingles on the roof.

Building a flat roof valley is no different than a plumber installing a drainpipe that is flat for a few feet just to accommodate some aesthetic feature. The valley area of a roof the straight lines formed when two different planes of the roof meet is a critical area that handles a tremendous amount of water run off. Essentially there are three main ways to shingle a roof valley.