Deck Mounted vs Curb Mounted Skylights: The Pros and Cons

A skylight can completely change a room or space in your home by adding tons of natural light and a fresh breeze. When deciding to install or replace a skylight, you need to decide what kind of mounting system is right for your home — deck mounted or curb mounted.

Here’s a simple break-down of the differences between these two types of residential skylights and which one is right for your home:

Deck Mounted Vs Curb Mounted Skylights: What You Need to Know

Deck Mounted Skylight
Deck Mounted Skylight

Deck mounted skylights are a newer design of skylight that lies more flush to your roof than a traditional curb mounted skylight. They are built with a wooden frame and a metal mounting flange, so they are directly secured and flashed to the roof deck. A deck-mounted skylight will protrude less from your roof, but give the inside of the room that same effect as a curb-mounted skylight.

Deck Mounted Skylights are best for roof pitches of 3:12 -137:12 pitch.

The Pros of Deck Mounted Skylights

Energy Efficiency: A major benefit of deck-mounted skylights is their energy efficiency. Because of how flush they sit to your roof, deck-mounted skylights allow less heat to escape in the cold Canadian winter.
Security: Because they are flush with your roof, deck-mounted skylights are more secure because they are more difficult for intruders to break into.● More Attractive: Although this is entirely subjective, most homeowners prefer the look of deck-mounted skylights. They are less obtrusive on the outside of your roof and don’t take away from your home’s curb appeal. On the interior, deck-mounted skylights have an inconspicuous built-in drywall groove that homeowners love.● Less Condensation: Deck mounted skylights have two features that help to reduce condensation. First, the built-in drywall groove provides a place where the skylight can be tied into the building envelope. This will decrease condensation from cold attic air meeting warm living space air in the winter. Curb-mounted skylights also use integrated gaskets to drain condensation to the outside, keeping humidity levels down.
Perfect for the Canadian Climate: The deck mount is designed to work in the Alberta climate and meets the new building code.
Ideal for Multiple Skylight Installations: Planning on adding more than one skylight to your home? Then you’ll need a certain type of flashing called Combi Kits. In this case, you will have to choose deck mounts.

The Cons of Deck Mounted Skylights

Shingle Removal: When installing or replacing deck mounted options, you will need to remove shingles around the skylight. You may also need interior finishing touch-ups.
Cost: Because deck mounted skylights are more labor-intensive to install, they can be more expensive than curb mounted skylights.
Set Sizes: If you hope to customize the size or shape of your skylights, deck mounted options won’t work for you, as sizes are restricted and there are no custom sizes available.

Is a Deck Mounted Skylight Right For You?

In our Canadian climate, we recommend Deck Mounts for new builds or new skylight installations primarily for the added energy efficiency. See our Deck Mounted Skylight Glass Options to help decide which is best for your application.


Curb Mounted Skylights

Curb Mounted Skylight
Curb Mounted Skylight

Curb mounted skylights are fastened upon a curb (typically a 2×4 or 2×6 wooden frame) so they sit above and off the roof deck.Curb Mounted Skylights are best for roof pitches of 2:12-20:12 pitch.

The Pros of Curb Mounted Skylights

Easy replacement: When replacing curb-mounted skylights, you often don’t have to involve the flashing if it is in good condition. That means you can change and fasten the new skylight down onto the existing curb relatively easily.
Customizable: If you need a custom-sized skylight, curb-mounted options are the way to go. You can order specific sizes to fit whatever space you need.
More Light: Because curb-mounted skylights have a larger glass area than similar-sized deck mounts, you’ll enjoy more natural light in your space, with a better view of the outdoors.
Durable Parts: In particular, the Velux curb mounted skylights come with a built-in sealing gasket. Other brands rely on adhesives which can break down over time, making the Velux option more durable.
Versatility: Fixed curb mounted skylights can be turned, giving the homeowner versatility with design options. But you don’t need to worry about condensation control– these skylights have condensation weepage systems on all 4 corners.
Works on Flat Roofs: Velux’s FCM curb mounted skylights can be installed on a completely flat roof. Although it is recommended to have a slight slope in the curb to prevent water pooling, it is not necessary.

The Cons of Curb Mounted Skylights

More Conspicuous: Unlike deck-mounted skylights, curb mounts are not flush with your roof. There is a higher profile, which some homeowners dislike.
Less Energy Efficient: The curb of curb-mounted skylights is only about 1.5 inches of wood, and this will be the only insulation. This has the potential for higher heat loss in the winter.

Is a Curb Mounted Skylight Right For Your Home?

Curb-mounted skylights are the best choice for those who want an easy replacement and already have curb mounts. They are also the only choice for flat roofs or non-standard skylight sizes. See our Fixed Curb Mounted Skylight Glass Options to help decide which is best for your application.


Our technicians are experienced at helping homeowners like you find the perfect skylight options for their property. Call or email us today to learn more!