SkyLeaks: The Greatest Myth of the Roofing Industry

Skylights get a bad reputation in the building industry for the wrong reasons. Many people will tell you, “you only need to replace your skylight when it’s leaking”, and “skylights always leak.” These people are typically homeowners who have owned skylights and claim that they’ll never do so again. However, a leaky skylight isn’t always the skylight’s fault – in fact, VELUX can almost guarantee that it isn’t. A leaky skylight is usually an indicator of a much larger roofing problem.

Skylights often leak because the incorrect roofing material was used around the skylight. We generally trust roofers, but we do know there are a few bad eggs, just as there are in any industry. Roofers who aren’t familiar with VELUX will hastily install the skylight, sometimes disregarding entire pieces of flashing and adhesive underlayment to install the skylight with their preferred method. The problem with this approach is that not all skylights are installed in the same ways.

We know this, because we also sell Wasco Skylights, which was ironically just purchased by VELUX Skylights. When Wasco was its own company, it used to boast about having the fastest and easiest installations – something that we still believe to be true. VELUX has kept a few of the old Wasco products, specifically the old E-Series which boasted the fastest installation time in the industry. While VELUX is integrating the old Wasco style of flashing and installing a skylight, the way the two models are installed are still vastly different.

VELUX Skylights use an adhesive underlayment, which is almost completely wrapped around the sides of a Skylight. The underlayment is then covered with a specific flashing type per the roofing material already being used. When all is said and done, the bottom portion of the flashing is covered with roofing material and simply screwed into the side of the skylight.

VELUX Skylight Mid Installation Drawing
VELUX Skylight Mid Installation Drawing

Wasco Skylights use a flexible rubber flange instead of adhesive underlayment. The flange is already attached to the skylight when it is placed on the roof. Then, UltraSeal Flashing is used on top of the gasket. Finally, new roofing materials cover the L-gaskets on the top of the skylight.

Wasco Skylight Before Installation
Wasco Skylight Before Installation

When replacing or installing a new skylight into your home or business, it’s always important to check with the roofer or installer to see what they think of the skylight they’re installing. Since VELUX is the industry leading skylight, you should find that most contractors and roofers will happily install a VELUX Skylight for you. Should you find a roofer that is hesitant about VELUX, or doesn’t like to adhere to the traditional installation procedures, you may want to think twice about hiring that installer. More specifically, if the installer starts talking about using caulk, FIND ANOTHER INSTALLER.

A bad skylight installation example with too much caulk and exposed flashing
A bad skylight installation example with too much caulk and exposed flashing

On top of that, VELUX’s No Leak Guarantee only holds if the recommended installation procedures were used. Yes, VELUX has a No Leak Guarantee designed to simplify this entire warranty process. While we plan to write another blog all about the No Leak Guarantee very soon, you can find out more here in our warranty brochure.

As always, these brochures and all of the installation guides for our products are on our website and ready to be downloaded from our Resources Page. Looking for another VELUX resource that you can’t find on our website? Be sure to ask Theresa – she’ll make sure it’s updated in a jiffy!