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The missing of drip edge flashings can cause several problems at the bottom of a roof, because these flashings serve a number of purposes:

• Drip edge flashings keep insects out of the attic.
• They prevent wind-driven rain from entering under the edge of the roof.
• They provide a “drip point” for water to drip off from the roof which helps prevent soffit or fascia rot.
• They keep shingles from “sagging” as they extend past the edge of the roof.

Solution:

If necessary, pop up roofing nails from the shingles and slide in a metal flashing. Glue the flashing and shingles with bituminous mastic.

The application of an underlayment provides benefits to the roof system at the deck and shingle components. These benefits add to the long-term weatherproofing success of the roof system. The most building codes require the application of an underlayment for pitched roofs. Shingle roofs without an underlayment or without proper overlapping mean high risks for wind driven water close by roof details (valley, chimney, skylight, spot vents, pipe flange etc.). When installing on a slope between 9.5° and 20°, it is very important to install double coverage with 50 cm overlaps or one layer of a self-adhesive underlayment!

Solution:

No action is needed if you do not have leakage problems. If you are experiencing water infiltration, try to fix the leak and start to think about a new roof.

A high quality roof is created when qualitative shingles are combined with a correct installation. Over the past weeks we showed you some of the most frequent roofer mistakes. After a while, these mistakes can cause some serious roofing problems.

To end these series, we would like to get your attention for these last 5 mistakes:

• Using a lot of bituminous mastic
• Wrong shingles for hips and ridges
• Improper sealing of penetrations
• Insufficient securing of valley
• Holes due to installation

Using too much bituminous mastic or roofing cement can cause blistering. The use of mastic which is not compatible with bituminous shingles can also lead to blistering.

Solution:

Blisters can disappear after some period. If they are already opened, it’s better to change these affected shingles.

Some roofers will cut shingles into pieces and use these pieces for the hip and ridge cap, regardless of which shingle is being used on the roof. With 3-tab, 4-tab, hex and diamant shingle this is the correct process. If this is done correctly, the shingle is cut into three even pieces (4-tab shingles in 4 pieces) that are flexible enough to use as a cap shingle. Do not use beaver shaped shingles for capping because they are too narrow and don’t cover hip or ridge enough!

The popularity of laminated shingles is increasing, but many roofers are making the mistake of following the same process you would with a 3-tab. The thicker Cambridge shingles are not designed for ridge caps. They do not lay flat and some may crack or break when you bent them over the ridges. It is highly recommended to use only a 3-tab shingle that matches the color of the laminated shingle.

Solution:

If your roof suffers leaking problems through the cap shingles it is necessary to change them with rectangular shape capping.