Shouldn't A Roofer Be Sealing Your Roof?

This is a photo of  an improperly terminated roof projection. This electrician was contracted to add light fixtures to the building. Wiring could be run through the walls of a building, but is much easier and less labor intensive to install on the roof. After running the wires on the roof, the electrician cut the roof membrane and decking to run the wiring into the building.

After encapsulating the wiring in pipes and boxes, the electrician sealed the area with a polyurethane-based insulating foam sealant. The conduit was then mechanically attached to a pipe block that was placed on the roof.

Here are 3 things that are incorrect with this:

1. Any work performed on the roof by a contractor that does not specialize in roofing related work could void the warranty!

2. The polyurethane-based insulating foam sealant does not properly accommodate the movement of the roof membrane and the piping. The conduit is made of steel, and the roof is a Thermoplastic polyolefin (TPO) membrane. These different types of materials experience different thermal cycles and therefore experience different movement. The conduit should have been flashed in one of the following ways:

A field-formed boot.

OR

A pre-manufactured boot

3. The flashing the electrician installed may eventually allow water to enter the roof system. Any water entry into the roof system could contribute to one or all of the following:
• Accelerating the degradation of the roof membrane.
• Saturating the insulation and lowering its R value.
• Promoting bacterial and mold growth.
• Compromising the indoor air quality.
• Allows water to enter the building.

All of this can be avoided by having a contractor that specializes in roofing install the flashing. Typically this type of installation is a field-decision and the building owner is unaware of it until after it has been installed.

Performing regular roof inspections with an industry professional allows you to detect, and replace these installations as soon as possible.

Here is a photo of properly installed roof projections. Imagine if all of these had been done incorrectly? How many potential leak sources would they have?

- Tommaso Costanzo, CDT, RRO, LEED Green Associate