05/20/2026
We see this done wrong 9 times out of 10.
A deck-mounted skylight installed on a low-slope roof is almost guaranteed to become a problem. These systems rely heavily on gravity to shed water and when the pitch isnât steep enough, water lingers, backs up, and eventually finds its way in.
Hereâs the difference:
Deck-Mounted Skylights
⢠Installed directly to the roof deck
⢠Designed for steeper slope roofs (typically 3:12 and up)
⢠Uses step flashing + shingle integration to shed water
⢠Clean, low-profile look but pitch dependent
Curb-Mounted Skylights
⢠Installed on a raised curb (built-up frame) above the roof surface
⢠Ideal for low-slope or flat roofs
⢠Elevates the skylight above standing water
⢠Allows for proper membrane/flashing tie-ins (TPO, modified, etc.)
⢠Built for long-term waterproofing, not just appearance
Putting the wrong system on the wrong roof is how you end up with repeat leaks, interior damage, and ongoing headaches.
If youâve got a skylight on a low-slope roof or youâre planning one, itâs worth making sure itâs done the right way.
đ Call/Text: 404-757-9824