Ice damming below skylight

Interior · Windows, Skylights and Solariums · printed page 366 (PDF page 367)

Book index entries

below Skylight Skylight – Ice Damming Below Skylight – Window and Solarium from the Inside and Window and Skylight from the Inside Skylight and Solarium from the Inside

Text in the illustration

problem
localized heat loss causes snow to melt around the skylight
the water refreezes when it hits the colder roof below - building up a dam
water running down the roof can back up under the shingles or skylight flashings
snow
skylight
water buildup
ice dam
attic
(insulation omitted for clarity)
heat loss
water entry
roof rafter
ceiling joist
exterior wall
solution
install Ice and Water Shield below the shingles for 6' around the skylight - this will prevent any backed up water from leaking into the building
cross section

Generated explanation

A roof cross section shows a domed skylight installed in a snow-covered sloped roof above an attic. Red arrows indicate localized heat loss around the skylight, which melts snow; the meltwater refreezes on the colder roof downslope to form an ice dam. Blue shading and arrows show water building up behind the dam and entering the building beneath the skylight flashing or shingles. Roof rafters, ceiling joists, and an exterior wall are shown, with insulation explicitly omitted for clarity. The illustrated solution calls for Ice and Water Shield beneath the shingles for six feet around the skylight to prevent backed-up water from leaking into the building.

Related illustrations

0083

Ice damming at skylight

· p. 22

A cross section shows a domed skylight installed in a snow-covered sloping roof supported by rafters, ceiling joists, and an exterior wall. An upward arrow indicates localized heat loss beside the skylight, melting nearb