A shingle offset is a method roofing contractors use to prevent butting joints between shingles. Many shingle manufacturers require this to ensure a properly installed roofing system.
Instead of placing your shingles evenly, one on top of the other, the roofer will move the singles over a couple of inches.
Each shingle manufacturer has a different requirement of what degree the shingles need to be offset. But, every manufacturer has some form of offset requirement.
The Importance of Offsetting Shingles
Installing shingles without an offset is dangerous for several reasons. Most importantly, it will cause the wind and rain to travel down your roof in a straight line. These straight lines are what we call intersecting channels.
In other words, instead of rain running evenly down the face of your roof, these channels act as funnels for the water to run down. As a result, the water will accelerate the erosion of the shingle.
Therefore, what is put there to protect your home from external elements will be washing away.
As well, these channels will be more susceptible to lifting during strong wind events. This will lead to shingle loss, broken seals, and a rippled surface on your roof.
6" Shingle Offset
How to know if your contractor is offsetting your shingles:
Offset shingles will be applied diagonally across each facet of your roof.
So, if you notice your contractor applying shingles vertically upward, they are racking your shingles. Although this is a quicker way to install shingles without frequent relocation of the application area, it puts your home at risk. It only serves to benefit the contractor's time.
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