by Kenton Shepard and Nick Gromicko, CMI®
The purpose of the series “Mastering Roof Inspections” is to teach home inspectors, as well as insurance and roofing professionals, how to recognize proper and improper conditions while inspecting steep-slope, residential roofs. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail.
Under a number of different circumstances, shingles may need to be hand-sealed. One example is when shingles have not bonded, or when the bond has been broken.
Another example is when the roof pitch exceeds 21:12, such as with mansard roofs.
Because of the angle at which it hangs, the weight of the shingle alone may be inadequate for proper sealing along the adhesive strip.
You’ll find steep roofs on other designs, too.
The type of roof design doesn’t really matter. If the roof is steep, or has steep or unusually shaped sections, be especially diligent in checking to make sure the shingles are fully bonded.
Rake edges exposed to high winds are especially vulnerable to uplift forces. Hand-sealing will help keep the roof in these areas intact.
As asphalt shingles age, they become stiffer, which actually improves their wind resistance. This advantage is offset by the fact that the bond strength of the adhesive strips can deteriorate over time, especially any contaminated adhesive strips.
Checking for Proper Fastening
In order to check for proper fastening, you’ll have to break the bond of the adhesive strip. Avoid doing this whenever you can. In breaking the bond of an adhesive strip to check the underlying fasteners, you destroy the integrity of the most important component in the shingles' wind resistance to check the condition of the second most important component, so you’re actually creating roof damage when you break the adhesive bonds of fully bonded shingles.
In a roof with shingles that are poorly bonded -- that is, you are able to break the bond by tugging lightly, or you see shingles that have been face-nailed, or you find loose or wind-damaged shingles -- the fastening system becomes more important, and it’s worth lifting a representative number of tabs to confirm proper fastening. Check different parts of each slope, especially slopes that are affected by conditions such as shade from other roof sections, trees, or geological features such as mountain ridges.
If you’ve broken the self-adhesive bond of a shingle, you’ll need to hand-seal the tabs so that they can’t be creased or broken by wind. If you make a habit of carrying a caulking gun with roof cement in your vehicle, this is easy to do.
To hand-seal shingles, use a tube of roof cement in a caulking gun.
For three-tab shingles, you’ll need to put a quarter-sized dollop of roof cement under the front corners of each of the three tabs.
Learn how to master a roof inspection from beginning to end by reading the entire InterNACHI series: Mastering Roof Inspections.
Take InterNACHI’s free, online Roofing Inspection Course
Mastering Roof Inspections
Roofing Underlayment Types
Inspecting Underlayment on Roofs
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