Mastering Roof Inspections: Roof Penetrations, Part 5

SKYLIGHTS

You’ll see skylight flashing installed using a number of methods, depending on the age of the type of skylight, the type of roof-covering material, and who installed it.

Self-Flashed

Self-flashed skylights come from the factory with flanges that fit against the roof. The flashing kits that come with them are relatively simple to install.

Curb-Mounted

Looking at a few key points will tell you about the quality of the installation. Above the skylight, shingles or slate should stop an inch or so short of the skylight itself to create a melt-water channel.

At the two uphill corners, the flashing should extend past the corner at least 1/8-inch. The type of flashing used on the sidewall and downhill sides of the skylight will depend on the type of roof-covering material installed.

As always, you'll be watching for and commenting on any broken skylights.

MECHANICAL ATTACHMENT POINTS

Various types of mechanical equipment installed on roofs have fasteners that penetrate the roof-covering material. Some examples are:

braces for chimneys,

air-conditioning equipment,

photovoltaic panels,

solar thermal panels for hot water,

satellite dishes,

Basically, anything that penetrates the roofing is a potential entry point for moisture and should be looked at closely, both on the roof and from inside the attic, when possible.