Flashings are the nemesis of homeowners. Ninety percent of all roof leaks are a result of flashing problems. Many homeowners experience confusion concerning flashings. I'm convinced that this confusion is based upon the fact that very few homeowners have had the opportunity to 'walk or crawl' a roof to see just what they are. Flashings are simply transition materials. They make the transition between roofing materials and things that project or stick through roofs. This linked article speaks to this subject.

The best flashing systems are constructed of metal. When constructed at the jobsite, these metals almost always require solder to fuse together separate pieces of metal into one leak-free piece. Caulk or roofing cement simply will not do. Only experienced roofers can construct soldered flashings.

Skylight manufacturers responded to this by making the flashing system an actual component of the skylight. These flashing systems require no solder, caulk, or roofing cement. They rely on simple gravity to keep rain water from entering your house. This is the same principle which has kept water from coming into hundreds of thousands of homes which employ sound roofing techniques.

The advantage to these pre-engineered systems is both leak free and rapid installations. Site built soldered flashings can take hours alone to fabricate. Pre-engineered flashings can be installed in minutes!

The Shaft

The most dramatic skylights are those that have flared shafts or light tunnels. The sunlight which enters the skylight must be funnelled into the living space. There are any number of ways to construct skylight shafts. However, more light will enter the room or space if you widen the shaft as it runs from the skylight to the ceiling below. The effect is comparable to operating a flashlight that has a lens which can be adjusted from a narrow beam to flood light position. Flared skylight shafts act like flood lights.

Complex skylight shafts can take time to construct. Often structural work has to be performed to transfer loads from ceiling or roof framing members that are altered to create the light tunnel. This type of work is not to be attempted by 'weekend warrior' homeowners who think they are master carpenters. If your house is constructed with prefabricated roof trusses, absolutely do not cut these framing members. Truss alteration is not always possible. In the few instances where it can be done, it must be approved by a structural engineer.

If installing a skylight shaft, always make sure to insulate the tunnel prior to applying the wall finish. Vast amounts of energy can be lost through these uninsulated spaces.

Also, always paint these shafts or tunnels with flat wall paint. Semi-gloss or gloss paint will accentuate any imperfections in the walls.

Engineered Flashing Skylight Manufacturers

• Andersen Corporation
• Pella Corporation
  
• Roto-Frank of America
• Velux-America