Asphalt Shingles spacing - overlap

[Zane Remenda]

Hi all,

I inspected a house where the distance of the overlap of the shingles on the roof was a bit shy of covering the bottom of the 3 tabs. You can see where the black part of the shingle is exposed in the photo.

I did a bit of research before posting here. The only thing that I could find that may be problematic is that the shingles may not have enought nails. Thus more susceptible to wind damage. Typically, a 3 tab shingle will have 4 nails into the "tar" line, then, another 4 from the above shingles. If the spacing is too long, there will be a shortage of nails holding the shingles in place.

There are also many nails that are showing without any caulking on them.

This is a 2011 development and there are about 20+ buildings similar to the one I inspected. The method of shingle installation seems to be similar on all the other buildings.

My questions is, would this be a method for the roofer to save money?

Are there any other consequences of installing the shingles this way?

Thanks

[Rick Cantrell]

Even though it does not look right, you need to know what exposure is recommended (allowed) by the manufacturer.

If you are unable to determine the manufacturer, use industry accepted practices.

[Jim Luttrall]

Hi all,

I inspected a house where the distance of the overlap of the shingles on the roof was a bit shy of covering the bottom of the 3 tabs. You can see where the black part of the shingle is exposed in the photo.

I did a bit of research before posting here. The only thing that I could find that may be problematic is that the shingles may not have enought nails. Thus more susceptible to wind damage. Typically, a 3 tab shingle will have 4 nails into the "tar" line, then, another 4 from the above shingles. If the spacing is too long, there will be a shortage of nails holding the shingles in place.

There are also many nails that are showing without any caulking on them.

This is a 2011 development and there are about 20+ buildings similar to the one I inspected. The method of shingle installation seems to be similar on all the other buildings.

My questions is, would this be a method for the roofer to save money?

Are there any other consequences of installing the shingles this way?

Thanks
Contrary to popular opinion and practice, the nails do NOT go in the tar strip. As noted above, check out the manufacturers installation guide and follow that.
As for consequences, failure to follow the letter of the installation instructions will allow for the possibility of voiding the warranty and blow off.

[Jerry Peck]

Contrary to popular opinion and practice, the nails do NOT go in the tar strip.

Actually ... some *are* specified to be in the sealant strip.


As noted above, check out the manufacturers installation guide and follow that.

Exactly.

Many architectural type shingles are, at least down here, nailed with the nails placed evenly spaced across the shingles, yet a review of *most* (all but one so far of the ones I've inspected) show that the installation instructions on the wrapper specify the nails placed as for 3-tab shingles. At least this applies for here in Florida where 6 nails per shingle are required, maybe that pattern is not required for areas which allow 4 nails per shingle.

[Chad Norlen]

I would call it out, due to the exposed nails, and the shingles don't appear to have bonded properly to each other. That much exposure will also make it easier for the wind to get underneath and rip tabs off.

Adhesive strips (http://www.nachi.org/asphalt-comp-shingles-part5-59.htm)

As an anecdotal observation, I put my roof on 10 years ago and haven't had any blow-offs yet (our wind rating here is 90mph for 3 seconds)

Chad
(Don't remember if I've made a signature yet)