The key difference between curb-mounted and deck-mounted skylights lies in how they are installed and attached to the roof.
Curb-mounted skylights sit atop a raised frame (the curb) built on the roof.
Deck-mounted skylights mount directly to the roof deck.
Curb-Mounted Skylights:
- Installation: Installed on top, like a shoebox lid, of a built-in curb frame on the roof. The curb is part of the roof.
- Ease of Installation: Generally easier to install, particularly for new construction.
- Cost: Can be a more budget-friendly when replacing the skylight.
- Appearance: The curb frame can be more noticeable and might not be as aesthetically pleasing for all roof styles.
- Energy Efficiency: Might have slightly lower energy efficiency than deck-mounted skylights due to the curb’s insulation is typically the thikness of the lumber..
- Roof Pitch: Suitable for a range of roof pitches, including flat roofs. Curbs are required for roof slopes less than 14°.
Deck-Mounted Skylights:
- Installation: Mount directly onto the roof deck, often with a self-flashing design.
- Ease of Installation: Can be more complex to install, especially on existing homes, requiring precise fitting of the opening.
- Cost: Might be more expensive due to the complex installation and potential for labor costs.
- Appearance: Provide a more streamlined, low-profile look that blends better with the roofline.
- Energy Efficiency: Offer better energy efficiency due to their tighter seal and lower curb.
- Roof Pitch: Generally suited for roof pitches between 14 and 85 degrees.
Summary Table:
| Feature | Curb-Mounted Skylights | Deck-Mounted Skylights |
|---|---|---|
| Installation | On a raised, site-built curb | Directly on the roof deck |
| Appearance | More visible, sits higher on the roof | Low-profile, blends with the roofline |
| Roof Pitch | Ideal for flat or low-pitched roofs (0-60¯)* | Suitable for pitched roofs (14-60°) |
| Energy Efficiency | Generally less efficient | Typically more energy efficient |
| Installation | Higher labor costs for building the curb | Potentially lower installation costs |
*Curb mounted skylights are required for roof slopes below 14°.
Curb-Mounted Skylights:
Installation: Installed on a raised wooden frame called a “curb” which is built on the roof deck.
Appearance: More visible from the outside due to the raised curb.
Suitable for: Often preferred for flat or low-pitched roofs where the raised curb helps with water drainage.
Benefits: Easier to install and replace the skylight itself without needing to re-flash the entire area. They can also be customized in various sizes and shapes.
Deck-Mounted Skylights:
Installation: Fastened directly to the roof sheathing.
Appearance: Offer a lower profile, blending more seamlessly with the roofline.
Suitable for: Best for roofs with a sufficient pitch (typically 14 to 60 degrees) to allow for proper water drainage.
Benefits: Generally more energy-efficient due to a better seal, potentially lower installation costs in some cases, and a sleek, modern aesthetic.
Ultimately, the best choice depends on:
Your roof’s pitch: Crucial for determining suitability and proper water drainage.
Desired aesthetic: Consider how the skylight will look on your roof.
Budget and installation costs: Curb mounts may be cheaper initially, but deck mounts may offer better long-term value in terms of energy efficiency.
Specific needs: Whether ventilation or a seamless look is a higher priority.