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Tarpaper Under or Over DripEdge

scottbennet's picture

I have a question that I believe was answered in the magazine but I can't seem to find it.  In the Dec 2011/Jan 2012 issue there is an article entitled "Stormproof Your Roof" which discusses application of self-adhering underlayment/flashing.  There was a follow-up that asked did the metal drip edge go under or over the tarpaper/building paper.  Can anyone help me out.  Thanks.

Think like water - imagine (post #206012, reply #1 of 8)

Think like water - imagine the path water will take and think of the primary path (shingle, flashing, drip edge) and the secondary path if water leaks in where it shouldn't (ice & water sheild, tar paper).   Most times water should shed off the primary path, but when it doesn't the secondary takes it safely away. 

An argument can be made for lapping the ice and water sheild over the drip edge, but in the normal course of getting the roof sheathing on and the roof dried in, the ice and water is put down first and the drip edge comes after.  On a roof that the owner wants the drip edge covered with ice and water I'll run the main ice and water under the drip edge with another 6" strip over it. 

I've seen a lot of guys who run the ice and water around the edges and down the valleys, then drip edge goes over that, then tar paper goes over the top of the drip edge.

 

 

Beer was created so carpenters wouldn't rule the world.

Think like water - imagine (post #206012, reply #2 of 8)

Think like water - imagine the path water will take and think of the primary path (shingle, flashing, drip edge) and the secondary path if water leaks in where it shouldn't (ice & water sheild, tar paper).   Most times water should shed off the primary path, but when it doesn't the secondary takes it safely away. 

An argument can be made for lapping the ice and water sheild over the drip edge, but in the normal course of getting the roof sheathing on and the roof dried in, the ice and water is put down first and the drip edge comes after.  On a roof that the owner wants the drip edge covered with ice and water I'll run the main ice and water under the drip edge with another 6" strip over it. 

I've seen a lot of guys who run the ice and water around the edges and down the valleys, then drip edge goes over that, then tar paper goes over the top of the drip edge.

 

 

Beer was created so carpenters wouldn't rule the world.

Drip edge (post #206012, reply #3 of 8)

Instructions are on the shingle packages.

At the lower end eave the drip edge goes on first and the felt paper  laps over it. On the rakes the the drip edge goes over the the paper.

Dave (post #206012, reply #5 of 8)

It almost never gets done that way.

Reason is because when building a house, you want that sheathing dried in as soon as possible, so you do the underlayment immediately after sheathing. Then you have time to get the fasia trim etc done. After the whole roof is ready, then you can strat roofing by applying the drip edge. I like to do vycor over the top of the metal before shingling myself, but don't think it is neccessary if the underlayment runs down far enough, especially on steeper roofs. A lower slope like 3 or 4/12 means I definitely want the vycor lapping to seal things up. Also on older homes where the insulation/venting is an issue and ice damns more likely, the vycor is more strongly indicated.

 

 

Oh Well,

We did the best we could...

Agree (post #206012, reply #7 of 8)

You right about what happens, but he was asking the reccomended installation.

I use ice and water shield on the lower edge and all valleys. 

Probably easier to do it the (post #206012, reply #8 of 8)

Probably easier to do it the "right" way when reroofing (vs new construction), since, on a not too big house, a good crew will do the entire job in a day or two, and the fascia will already be in place.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

I think sometimes roofers (post #206012, reply #4 of 8)

I think sometimes roofers will put the drip edge over the paper/shield, whether this is the "right" thing to do or not.  This lets them put all the edge on at once, avoids possible damage to the edge in earlier work, and ties down the paper.

But my understanding is that the "right" way is to put the eve edge below the paper, and gable end edge on top.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

It's all a matter of (post #206012, reply #6 of 8)

It's all a matter of practical technique considering what the conditions are.

The two times when it beomes ccritical are when there is a lot of ice damning, or when the HO is trying to get 25 years out of a 20 year shingle

 

 

Oh Well,

We did the best we could...