Posted by VELUX Skylights on April 3, 2020

Installing Skylights on Different Types of Roofs


Let's be realistic: you're probably not going to be the one who physically installs your skylight. Unless you're experienced in construction or roof work, installing skylights is not your typical DIY housing project.


Still, that doesn't mean you can't be informed on all the ins and outs of your skylight installation. And one of the biggest factors that determines which skylight you get and how it's installed is the type of roof you have.


Roofing Materials and Installation Types

Generally, your roof is going to fall into one of three categories: a shingle roof, metal roof, or tile roof. Metal roofs can only support deck-mounted skylights, but if you have shingle or tile roofing, you have the option to choose between deck-mounted or curb-mounted skylights. Now, what the heck do deck- and curb-mounted mean?


Deck-mounted skylights are nailed directly to your roof deck (the trusses and joists between the structural components of your roof). This gives them a lower profile on your roof and makes them ideal for new construction homes or brand new skylight cut-ins.


Curb-mounted skylights are more common on low-sloped roofs. They're installed on a curb or frame - usually made of two-by-fours - that your installer attaches to the roof. Think of curb-mounted skylights like a shoebox: the curb is the box and the skylight is the lid.


Both deck- and curb-mounted skylights look the same from the inside, so your roof's type and slope will likely be the determining factors for which style you install. But for a skylight installation to be complete, you need flashing.



VELUX Flashing Kits

Flashing is the material that creates the seal around your skylight's deck or curb mounting. As such, VELUX's Flashing Kits are a crucial part of our complete leak-free system. But whether you're getting deck- or curb-mounted skylights, VELUX has a variety of flashing kits that ensure a weather-tight fit for virtually all roof types and slopes.


Our flashing combined with two other materials, a pre-attached deck seal or gasket and an adhesive underlayment, make up the three layers of protection we talk about in our No Leak Promise. Together, these materials guarantee a 10-year installation warranty against leaks and any other issues that may arise.



Skylights and Flat Roofs

Now, let's talk flat roofs. Believe it or not, your roof doesn't need to have a slope to install a skylight. In fact, VELUX has a few options for skylights made specifically for flat roofs.


The main issue skylights face on flat roofs is rainwater collecting on top. VELUX's Flat Roof Skylights are slightly curved on top to prevent this. With a slight curve and our Clean, Quiet & Safe glass, rainwater whisks right off the skylight while featuring a clean interior appearance.


Speaking of interior appearance...


Coming Inside: Flat vs. Vaulted Ceilings

Now, all of this is moot if you have flat ceilings inside, right? Skylights can only be installed if you have vaulted ceilings, right?


Actually, this is one of the most common misconceptions regarding skylights. While it's true that vaulted ceilings require less work to install skylights, flat ceilings are no reason not to have the daylight you want. If you have a flat ceiling, once your skylight is set on the outside, your installer will construct a drywall light shaft inside. If you cut your house in half, it would look kind of like this:


Interior light shaft

As you can see, the shaft directs daylight down into the room below while hiding the attic space between your ceiling and roof.



Now that you've got the info, are you ready to install? Find an installer that's been certified by VELUX near you with our handy installer locator!