Drip edge?

[Ironman1079]

Hi, i am stripping 2 layers of shingles off my garage roof and re shingling it.

I was told that the metal drip edge you buy goes on before the tar paper but according to my home depot repair book, it shows the bottom peice going on before the tar paper and the peices from the eave to he ridge going on after.

my ? is:

Does drip edge go on before or after the tar paper?

thanks.

[deejoe]

Drip edge normally is one peice, bent to simulate the slope of the roof.
The vertical edge goes against the facer board or inside eavestrough(gutter).This vertical edge should have a slight "kick-out"near the bottom which will divert any water away from the facer, or into the trough.
The other top(near horizontal) edge should lay flat to the roof sheathing and nailed into place.
Imo, the paper can be applied either way, over or under.

[AllanJ]

Advantage of horizontal drip edge at eaves under the tar paper: Follows the rule that the layer of material higher up on the roof is on top of the layer of material further down. If water gets under the shingles onto the tar paper the water will flow down and off the edge of the tar paper over the outside surface of the drip edge and drip off, not likely to wick between the tar paper and wood sheathing.

Advantage of side drip edges along gables on top of tar paper: Reduces the number of entry points along the roof/wall line for water given the various layers of material. The drip edge keeps water from getting between the tar paper and sheathing. Then the only entrance is between the shingle and drip edge. The drip edge is generally ridged so water getting on the upper surface is more likely to follow the drip edge all the way down instead of work its way further in and onto the tar paper and/or under the drip edge and/or under the tar paper.