Making a hole in a roof is many an amateur’s most worried moment.
They know how do “solder-on” connectors, how to tune their amp, how to drive a ground rod, and they know they are deep trouble if their rooftop installation leaks into their home.
Like they say, that which goes up….coax, cable, wire or support… then, water comes down.
Each Roof System needs a specific Roof Penetration Technique to make a watertight roof flashing.
Shingles, EPDM, Built-Up Roofing, Metal, Thermoplastics, Specialty Systems, and even Waterproofing Systems under “Green Roofs” all have specific techniques to make an effective penetration.
It is not just getting a “Water Seal,” but for many of use reducing or eliminating “Thermal Bridging” is the goal of a successful roof penetration.
Common techniques historically have ranged from just poking the cables through, caulking them at the surface of the roof, to dedicated roof portals with rain, wind, insect, temperature, Air-Transfer, Security and Lightening Protection built in.
Between these two extremes fall most penetration styles.
First lets group the possible roof systems into those almost always needing professional help to do right, and those a skilled amateur should have little problem with:
Systems Usually Needing Professional Help:
- Coal Tar Pitch
- Many Thermoplastics (PVC, TPO, CPE, KEE)
- Green Roof Systems
- Many Metal Roofs (specially double layered systems)
- Certain Types of Liquid Applied Systems
- Other Specialty Systems
- Any System with a Warranty that limits modifications to Approved Installers
Systems that are often user-friendly:
- EPDM Systems
- Some Built-Up Roof Systems
- Some Modified Bitumen Systems
There is a huge amount of resource on the internet on how to work with each and every roof system.
Some good references are:
(and there are hundreds more)
My profession puts correctly installing roof penetrations to the test daily. As there are far too many systems and conditions to write about each one, post a comment if you’re interested in some input on a roof penetration issue affecting your shack.