Installation Details · FAQ

What causes most skylight leaks?

Failed flashing kit, by a wide margin. The glazing seal does fail eventually but accounts for maybe 15% of leak claims. The other 85% are flashing failures: the head flashing (above the skylight), the apron flashing (below), or the step flashing along the sides.

Trill installs the manufacturer’s matching flashing kit on every skylight install, never site-fabricated alternatives. Velux, Fakro, and Sun-Tek all engineer their flashing to match their frame geometry exactly. Generic flashings sold separately are dimensionally close enough to install but tend to develop small gaps within 8 to 12 years that show up as ceiling stains long before they look like obvious roof leaks.