Zippering On Roof

Walk with kelly roofing as they show you some of the hidden wind damage that can be caused by heavy winds.

Zippering on roof.

During your roof assessment have you identified displaced shingles on the roof. Frequently asked questions and answers about how to assess repair or prevent wind damage to roofs. If new roof installation happens in extreme conditions of cold or heat it won t last as long either. Roof wind damage assessment and caused for asphalt roof shingle defects.

Are these displaced shin gles the result of wind forces or from slippage. When they lift in a straight up line like a zipper it is known as zippering go figure. Image 4 image 3. Many pros shingle in a vertical line up the roof because it s much faster.

These are usually a result of repeated cycles of expanding in the heat and contracting in the cold. Known in the trade as vertical racking or staggering this how to lay shingles method enables the roofer to install a single column of shingles all the way to the peak without the wasted back and forth motion necessary to fill several rows of stair steps. This extra uplift pressure is generated at the edges by the additional pressures from the secondary movement of the wind as it encounters the wall and then rushes up over the roof figure 1. These unbonded overlaps will not vary in direction or increase decrease in areas of the roof where wind uplift would be greater less.

Many times after the wind leaves these zippering impressions the shingles will reseal however they reseal at a severely diminished value approximately a 90 diminished uplift resistance value. An unbonded pattern of shingle tabs in a racked installation is commonly referred to as zippering chalk lines in figure 6 show the nonbonded shingle portions. Photos and text guide diagnosis of asphalt roof failures how to identify and explain roof shingle failures obtain claims assistance contribute failure information at this website. The dirt and debris that will inevitably get embedded into the exposed mastic cannot be cleaned thoroughly enough to ever be reusable.

For example the shingles at the edges of a windward roof slope are exposed to higher uplift pressures than the shingles near the center of the roof slope. Are there adjoining shingles that have. The following is a list of questions to consider when you as the inspector are assessing a shingle roof for reported wind damage.