Search

Missing starterstrip on shingles roof. Roofer mistakes.
Wrong position starterstrip on shingles roof. Roofer mistakes.

2. Improper slope

Always use the right shingles to match the slope of the roof. Minimum slope for the majority of shingles is 15°. Cambridge Xtreme is the only shingle that can be installed from 9,5°. For vertical walls with 90° slope self-adhesive shingles must always be used.

Roof mistakes low slope roofer mistakes
Wrong slope on shingle roof. Roofer mistakes.

3. Incorrect shingle overhangs at the eaves

The edge of shingles must overhang the eaves between 6 mm and 10 mm. More shingles overhang can cause the shingles to be blown off in high winds and fewer overhangs can allow water to seep into wooden structure.

Solution:

Try to build up and slide in a new drip edge flashing to protect the wooden deck against driven water. Always secure the added metal flashing and shingles with Shingle Stick.

Incorrect shingle overhang roofer mistakes

4. Neglecting to install drip edge flashing at the eaves

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.

Install drip edge flashing at the eaves roofer mistakes
Flashing missing roofer mistakes

5. No or improper applied underlayment

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