Problems with too much exposure on asphalt shingles?

[Randall Clark]

Other than potentially exposing nail heads, what are some other problems too much exposure on asphalt shingles can cause? Increased chance for wind lift?

[Vern Heiler]

Other than potentially exposing nail heads, what are some other problems too much exposure on asphalt shingles can cause? Increased chance for wind lift?
If the exposure is correct and the nails are in the nail line, the nails are driven through two layers of shingle (the top and the one beneath) if the exposure is too great the nail only goes through the top shingle.

[Matt Bezanson]

Other than potentially exposing nail heads, what are some other problems too much exposure on asphalt shingles can cause? Increased chance for wind lift?
Most shingle manufacturers specify the amount of expose for their product. If the installer consistently ignores that spec, or any other, the warranty on the shingles in unenforceable. So the builder told the home buyer "These are 30-year shingles!", but because the nails are in or above the sealant strip, or the expose is wrong or the butt joints are staggered incorrectly, they are actually "Zero year shingles".

[Jerry Peck]

but because the nails are in or above the sealant strip,

Matt,

Careful on that presumption - some manufacturers actually specify that the nails are allowed to be in the sealant strip or above the sealant strip - shows the nail locations like that on the drawings on the packages.

Some even have lines printed along the shingles to designate nail locations, some have multiple lines - between two lines for below 7/12 and between two close spaced lines for 7/12 and greater.

The nail location varies by manufacturer and by shingle type/style.

[Dirk Jeanis]

Other than potentially exposing nail heads, what are some other problems too much exposure on asphalt shingles can cause? Increased chance for wind lift?
It doesn't matter what the effects are of having too large an exposure. You have no warranty nor do you have assurance of a water tight system. It is rejectable, period.

You should especially wach a few courses from the eaves, this is where adjustments begin so there will be proper exposure at the ridge lines. It is the least visible place from the ground and I have seen adustments that exceed the maximum design exposure. Pretty expensive to repair as well.