What I Look For Around Skylights

One of the first things homeowners assume when they see water around a skylight is that the skylight itself has failed.

That's not always the case.

Sometimes the problem is the skylight. But I've also found leaks caused by failed or improperly installed flashing, deteriorated shingles around the skylight, exposed fasteners, or problems with the roof itself.

That's why finding the actual source of the leak is so important before recommending replacement.

Water showing up around a skylight doesn't necessarily tell us where it's getting in.

During an inspection, I look at the condition and age of the skylight, the flashing system, shingles surrounding it, and the roof decking. I also look for signs of previous repairs or caulking that may indicate an ongoing problem.

In some cases, repairing the roofing or flashing around the skylight may solve the leak without replacing the skylight.

In other cases, particularly with an older skylight or a failed glass seal, replacement may be the smarter long-term decision.

The important part is figuring out the cause before deciding on the solution.

This is something homeowners can't see from the ground.

Once an old skylight and the surrounding shingles are removed, we sometimes discover deteriorated or rotted roof decking underneath.

That's why I like to inspect these areas carefully. If damaged decking is found, it needs to be removed and replaced before the new skylight and flashing system are installed.

Several of the photos above show exactly what we've uncovered during actual skylight projects.

This is a question I get quite a bit.

If an existing skylight is relatively new, in excellent condition, and compatible with the new roofing system, replacement may not always be necessary.

But if the skylight is older and you're already replacing the roof, it's worth seriously considering replacing it at the same time.

The shingles and flashing around the skylight are already being removed. Replacing an aging skylight during the roof project can avoid having to disturb a newer roof several years later when the skylight eventually reaches the end of its service life.

I look at the age and condition of each skylight before making that recommendation.

For skylight replacements and new installations, I use Velux skylights and their matching flashing systems.

I'm a Velux Certified Installer, and I like installing the skylight as a complete system rather than trying to improvise flashing around it.

Proper installation matters just as much as the skylight itself. A quality skylight installed incorrectly can still leak.

A skylight leak shouldn't automatically turn into a skylight replacement.

First, find out why it's leaking.

If the skylight is in good condition and the problem can be properly repaired, I'll tell you.

If the skylight is old, deteriorated, or replacement makes more financial sense while we're already working on the roof, I'll explain that too.

My philosophy with skylights is the same as the rest of the roof:

Repair when you can. Replace when you should.

— Keith Nagy
Owner/operations 

Nagy Roof and Repair