How many nails should you drive into your roof?
From time-to-time, Mike & I are asked about roof penetrations
* and whether we recommend nailing or bolting things to your roof. When asked if it is a good idea our answer is typically "It depends".
*Roof Penetration: Intentionally making a hole in your beautiful roof. (Reference:
Purgatory, Punishment Time Line Recommendations for Voluntary Roof Penetration)
It depends on what kind of roofing material you have, cement tiles are much different than composite shingles.
It depends on how many roof penetrations (nails or bolts) you are going to make & how big they will be.
It depends on how good of a job you will do and the complexity of whatever it is you are mounting on your roof.
It depends on how much work you are willing to do after you have secured whatever-it-is you put on the roof.
We always recommend using mastic on every roof penetration. "Cool" you say "but what is mastic?"
My source for this bit of info is:
http://www.pmel.org/Roofing-Glossary.htm
Mastic: See asphalt plastic roofing cement.
Asphalt: A bituminous waterproofing agent applied to roofing materials during manufacturing. Asphalt plastic roofing cement: An asphalt-based cement used to bond roofing materials. Also known as flashing cement or mastic; should conform to ASTM D-4586.
Now that we have the technical stuff out of the way, suffice it say that, typically, mastic is the thick, black or gray, goopy stuff you see on roofs quite commonly. It is used to seal roof penetrations. (Please reference definition & punishment guidelines mentioned above). Here is an example where mastic should have been used but wasn't.
This picture brings to mind what this handyman must have been praying while mounting the basketball hoop.
"Dear Jesus, please make it rain in my attic to wash away the dust."
This is a likely outcome without the use of mastic to cover the roof penetrations.
If you see big splotches
** of mastic on a roof it is a potential indicator of a past or present leak and that the roof is quite likely approaching it's design life. Yes, things happen in life that could mean only a small area of the roof needs repair or replacing and that the rest of the roof is fine, but, in general, (or in second-lieutenant) big splotches of mastic on a roof are not a desirable thing, period!
ch)
