There are several layers within a proper roofing job that are necessary to provide the most protection against water damage. Of all of them, the first line of defense is to install drip edge flashing. Unfortunately, many contractors tend to neglect this step.
The elimination of this installation can end up being your future nightmare. So, if you are re-roofing your house, be sure to demand a drip edge. If your roof is already finished (sans drip edge), you can still do a drip edge retrofit installation.
What Is Drip Edge Flashing?
Drip edging is a strip of flashing that is applied to the edge of roofing prior to the installation of other items. It is designed to protect the roof’s sheathing from water damage caused by rain, snow, or ice being blown or rolling back beneath the edge of the shingles.
When placed on the eaves side of a roof, the drip edge will prevent capillary action water damage caused by surface tension. When placed on the rakes’ side, it protects the sheathing from wind driven (or forced) rain blowing back into the sheathing.
Why You Need a Roof Drip Edge
Without the installation of a drip edge, water can wick into the edges of the roof sheathing and cause the roof to develop rot and/or mold. In worse cases, a leak will develop in the ceiling or along the walls.
Although it is not the intention, drip edge flashing will also provide protection for the fascia board. Because the drip edge directs the water directly down and into the gutters, the back of the fascia is protected from excessive moisture. This helps to extend the life of the wood.
Another benefit that wasn’t intended but has been a useful outcome from installing a drip edge is that it prevents rodents, squirrels, and birds from being able to access the attic space via the builder’s gap. If you have ever had a family of squirrels living in your attic, you can appreciate this extra bonus.
Why Doesn’t My Roof Have a Drip Edge?
If your house is like many, you may find that you do not have drip edge flashing installed. Often the common practice is to leave out the drip edge and compensate by installing asphalt roof shingles so that they hang over the edge by an inch or two.
This has been a common practice that is becoming less and less popular. It is now more frequently understood that a roof needs this extra protection. In 2012 the Internation Code Council changed things to reflect the requirement of drip edging on all asphalt roofs.
Parts of Roof Drip Edge Flashing
How to Install Drip Edge Flashing to a New Roof
To install a drip edge on a newly constructed roof or on a re-roofing job, attach the drip edge along the roof’s eaves first. The roof leg should extend a minimum of 2” back onto the roof sheathing. While the vertical leg should be placed 1/4” – 1/2” away from the fascia.
Omitting the spacing between the fascia and the drip edge is a common mistake that contractors often make. It is not uncommon for them to place the drip edge right against the fascia.
Doing this will cause surface tension water to roll back onto the fascia. The end result is quickly deteriorating wood. So, make sure you have that gap.
Next, roll out and install the underlayment or felt. The proper layering is for the membrane to be installed over the drip edge at the eaves and under the drip edge for the rakes.
Video demonstrating water run-off without drip edge and with proper placements vs incorrect placement.
Corners and Joints:
All joints should overlap by about 2 inches including joints made at or near the corners.
Outside Corner Cuts
To make the outside corner turns, place a straight cut through the roof leg. Make sure that you are wrapping a minimum of two inches. For Florida residents, the requirements call for 4” overlaps.
Bend on the vertical leg and make sure the flap on the roof leg is on top of the roof leg of the eaves.
Inside Corner Cuts
To make the inside corner turns, you will need to create an overlap that meets at the interior of the corner. That means that you will make cuts at the ends of two sections of drip edging and overlap the two at the juncture.
A common mistake made by contractors is to place a straight cut down the roof leg (same as shown for the outer corner) and then bend the section into the corner. However, doing it this way leaves an exposed square of sheathing right in the center of the valley.
Although this section will be covered with membrane, the valleys are one of the most vulnerable spots for water damage. Water run-off is very heavy in these locations and it is best to make cuts that prevent any exposure.
To make proper cuts and bends for the inner corners, place a cut line at the location where the roof leg meets the vertical leg.
Cuts for the Rake Side
After the membrane is installed, attach the drip edge to the rakes making sure to start at the bottom and work your way towards the peak. This ensures that a step effect is achieved which will allow the water run-off to move correctly.
There are a few recommendations out there for making the bends and the cuts at the peak of the rake side. I have experimented with several but found my method to be far easier and just as effective.
To do the rakes, I align my drip edge piece up with the peak and make a cut straight up through the vertical leg. Then, I make the bend on the roof leg over the peak.
Next, I place a line down the other side of the vertical leg, again using the the peak seam as a guide. Then, I snip off the kick-out that crosses over that line. This allows the overlap section to fit flush beneath the front drip edge piece.
Finally, I slip the overlap beneath the first cut and apply a thin bead of 100% silicone along the seam for extra assurance.
Types of nails to use:
For most applications, the use of galvanized roofing nails is the best practice. Always use the appropriate nails and/or adhesive that is required by your local code.
Where to place nails:
Nails should be placed along two separate rows in a staggered “W” pattern. The maximum spacing is 12” on center. However, 10” on center is a better spacing and will give a better performance.
If you live in an area where high winds are an issue (i.e Florida), the recommended spacing is 4” on center. This spacing varies from one location to another. So, be sure to check your local code requirements.
Install Drip Edge Flashing to Old Roof
When installing drip edge to a finished roof, the process is the same with one not-so-tiny addition. Ideally, you want to be able to nail the drip edge in place without doing any damage to the roof shingles.
This often means that the lower run (starter shingles and 1st course) have to be removed or loosened enough to allow access for tools. Removal will provide the easiest install for the drip edge.
If removal of the roof shingles is not an option, you can still get some good protection by doing a cement attachment. Doing this is a subpar installation method to using the above method, and does not meet the standards set by the International Code Council of using mechanical attachments, but is still better than having no drip edge at all.
To use this method, you will need to loosen the lower run of shingles with a putty knife. Then, slip the roof drip edge under the shingles (and the tar paper on the eaves). Place a bead of roofing cement along the top edge of the drip edging and press down on the loose shingles.
To prevent causing damage to the roof shingles, it is better to do this when the temperatures are warm enough to make the shingles pliable. In cold temps, the roof shingles become stiff and brittle and will break very easily.
In addition, the warmer temps will allow the loosened shingles to reseal themselves in a quicker fashion. If you have to wait out the cold weather for the seal to retake, you run the risk of wind damage in the interim.
So, try to time all repair work that requires lifting or moving roof shingles to coincide with temps around 70 degrees. This includes shingle repairs and/or installing gutter guards.
How Many Wrong Things Do You See?
I wanted to include examples of some mistakes that you want to avoid and explain why these will cause issues. In the image above, the handyman is doing several things incorrectly.
First of all, the drip edge that he is using has a vertical leg that is way too short to fit inside the gutter. This, in and of itself, isn’t necessarily wrong, but it is a combination of mistakes that make it a bad install.
The whole point of installing drip edges is to direct the water into the gutters and away from the fascia and house foundation. To correct this situation, make sure to purchase drip edge flashing with a long enough vertical leg to reach the gutter. If the gutters have been installed too low, they may need to be raised and corrected.
If you find yourself in a situation where you are using drip edging that can not reach your gutters, you can still increase your protection by using the proper drip edge to fascia distance. Unfortunately, this is the next mistake that he is making.
He is placing the drip edge right against the fascia. If spaced properly, the drip edge would still provide some protection despite the gutter issue. But installed this way is going to result in surface tension water running down the face of the fascia board and behind the gutter.
To correct this mistake, the drip edge should be pulled forward by 1/2”. This will help keep the run-off from reaching the fascia board and will allow it to drip down into the gutter.
Although this is not as good as having the drip edge inside the gutter, it is far better than the way he is doing it. However, it still exposes the fascia to windblown rain which will also run down behind the gutter.
The next thing that just jumps out to me is that he is not creating the proper overlap at the corners. You can see that he is snipping the corner flush with the eaves side and is doing the same with the rakes’ side.
What is going to happen in this situation is the rain is going to run down the corner and wick back between the space where these two sections meet. You should never, never, never butt two seams up against each other when doing any type of flashing.
To correct this situation, make sure there is at least 2” of drip edge available to wrap around the corners. (more if your situation or code merits it). Learn how to do the proper cuts to make the wraps. Practice on some scraps if needed.
Situations You May Face:
In a perfect world, the drip edge would be installed prior to roofing shingles. The vertical leg would extend down into the gutters and not have any face nails or screws. It would be spaced 1/2” away from the fascia board and be supported by 1/2” furring strips.
In an imperfect world, you are likely to find that retrofitting drip edging presents you with some questionable situations. For instance, how do you install drip edge flashing around gutter clips that are in the way?
Some may tell you to make two relief cuts around the gutter clips and fold the tab up. I don’t like that method because it interrupts the continuous barrier desired. There is no way to overlap these cuts and water can work its way behind the exposed edges.
Instead, I prefer to place the clip screws through both the gutter and the drip edge. I always swap out the old screw with a fresh one (roofing screws with sealing washers) and then apply a dollop of 100% silicone over the screw for extra security.
Things to Remember
The drip edge should always be installed with the flashing under the felt on the eaves side and over felt on the rakes unless local code dictates otherwise. A few places (Florida) may require an alternative way of drip edge installation.
Generally, they want it installed so that the drip edge must go over the underlayment and then be cemented to the shingle’s starter course and/or tar paper.
The best practice is to always install the drip edge so that it is inside the gutter. The whole purpose is to direct the water into the gutters. It should never be installed outside the gutter (i.e against the fascia board).
For proper water drainage, the drip edge on the rakes should always overlap the drip edge on the eaves. This works out correctly if you do the eaves first. Then, finish by installing the drip edge flashing on the rakes.
Use the nail spacing and pattern dictated by your code and/or location. Avoid placing nails within 1 1/2” of the roof edge. Always set the nails back close to the edge of the roof leg.
In some locations, it is acceptable for the roof shingles to line up with the drip edge. However, when permitted it is best to have the roof shingles hang over the drip edge by a minimum of 1/4” and a maximum of 3/4”. When combined with the drip edge spacing, the shingles will clear the fascia by 3/4″ – 1 1/4″ total.
Remember that every region, city, or local may have slightly different requirements. It is best to double check these instruction against your local code.
Final Comments
Regardless of the type of drip edge that you use, or whether you are installing drip edge on a new roof or are retrofitting an old roof, you should always follow your local code requirements. In addition, you should follow the shingle manufacturer’s instructions for installation.
Keep in mind that going outside of the shingle manufacturer’s requirements can void your warranty. You want to weigh any situational adjustments against that risk.
Did I miss something? Drop a question or comment below and I’ll answer or respond.
Kathleen Bonfoey says
I had gutter guards installed a few years ago called Gutter Helmets. I think there may be some controversy over these particular guards. If I remember, they are installed under the first shingle. Does that provide some of the same protection as a drip edge?
Rachel Lynn says
Hi Kathleen, The gutter helmet issue is that unless the roof slope is steep enough, water can be forced backward under the shingles. With a drip edge, the flow is straight down. Even with drip edging added beneath the helmet guards the damage can still occur. You can overcome these issues by using drip edging that extends several inches further back on the roof than the helmet guards, preferably with the guards placed over the top of the drip edge. That would provide you protection but it also may or may not void your warranty with the helmet guards. If your roof slope is adequate, you may never experience a problem and may prefer to let sleeping dogs lie.
Peter Rockwell says
Rachel Lynn,
Enjoyed your write-up on roofing drip edge. In your section, “Situations You May Face” on how a drip edge and gutter hangers can play together, you wrote that you don’t like to snip the drip edge around the hanger. Instead, your advice is “I prefer to place the clip screws through both the gutter and the drip edge. I always swap out the old screw with a fresh one (roofing screws with sealing washers) and then apply a dollop of 100% silicone over the screw for extra security.”
I like that detail a lot. I have problem gaps along my eaves, between the sheathing and fascia. This detail provides a continuous metal barrier to water and critters, from the top of the starter metal to the bottom of the gutter. Why not use this detail as a standard?
I can see a problem with water working upward between the drip edge and gutter by capillary action. So why not apply a continuous bead of sealant all along that joint and make it water proof?
The biggest problem I see: On my planned re-roof job, the roofing people don’t want to fuss with gutters. I have asked. And a gutter contractor charges big $ to do detail work like this, since their real interest is in installing new gutters.
Interested in your comments.
Peter Rockwell
Camano Is, WA
Rachel Lynn says
Peter, you are correct that roofers won’t install gutters. That’s generally not something they are equipped to do. However, the drip edge is typically part of a roofing job. What you want is to get the roofers to install the drip edge, leaving room for the gutters. Then, the gutter guy will come in and finish up. If you don’t have a General Contractor, you should check with the gutter guy to see if there are any specific issues to take into consideration with the drip edge and pass those along to the roofers.
Todd says
Rachel, thanks for the well-written article– it provides clear and valuable insight for my roofing project. One question: several of your photos show a brown colored drip edge along the rake/gable side, which is different than the pictures of the galvanized roof edge in other photos. The brown drip edge has a raised lip which the shingles butt up to (my guess is to further prevent wind/water infiltration along the rake edge). Aesthetically it has a nice look, compared to the alternative of a shingle overhang at the gable, although I could also see the tendency for water to find its way beneath the shingle at the point where it butts to the lip on the drip edge. Anyhow, there is no mention of this variety of drip edge in the article, so I am curious as to your thoughts of doing it this way, vs with the galvanized type depicted in the other photos.
Rachel Lynn says
Todd, You are correct. That was done to further prevent water infiltration. (notice the flashing cement between the paper and drip edge). However, this was in a high-wind area and was required. I don’t like that particular style of drip edge. As you noted, the lip can also retain water and allow entry at a vulnerable spot in the future. This image was used mainly to demonstrate the correct order for installation more so than to suggest the style. I would go with the standard drip edge and allow that overhang unless code dictates otherwise.
Todd says
Thanks! :)
Nooter Dooter says
I am adding drip edge to my shed. When installing the drip edge along the eaves (no gutters), when overlapping two pieces, is there a cut I should be making to properly marry the two, or do I just place one directly over the other? Silicone the seam?
Rachel Lynn says
Nooter Dooter, Just one over the other with at least a 2″ overlap and silicone the seam.
Josh Anderson says
I’ve recent had my roof replaced, continuous drip edge installed but during initial demo the facia boards were damaged. GC didn’t catch it until I pointed it out, they came, removed the newly installed gutters, snipped each corner of the drip edges inside and outside corners and then screwed it back up after facia and gutters reinstalled. I’m not happy a I no longer have a continuous drip edge and the corners are only now caulked. I’m wanting drip edges replaced, can it be done now after we just reroofed?
Rachel Lynn says
Hi Josh,
As long as it is a standard drip edge, they should be able to lift the 1st course of roofing shingles and remove a portion of the drip edge. Then, replace it with correctly overlapping corner sections. If the rest is correct, there isn’t any reason to do a whole tearout. Just make them redo/replace the drip edge within a few feet away from the corners.
Josh Anderson says
Awesome thank you Ms. Lynn for the advice!
Rachel Lynn says
Anytime!
Brian K says
A well regarded sunroom manufacturer in our area has almost completed our screen in deck, with a gable room. The rake side has shingles that extend about 2″ over the drip edge. Should I demand that the shingles me trimmed or I am worried over nothing?
Rachel Lynn says
It depends. It is standard in many areas to allow 1-1.5 inches of overhang if there is no drip edge installed. With a drip edge, it should be around 3/4″. Too much overhang can cause the singles to crack from lack of support or cause them to catch in strong winds. However, city requirements may vary from one area to another. So, I would first check with your city code. Then, make your decision based on what your local requirments are.
Kimberly Siegel says
I want to install drip edge and gutters on my 32 year old home. I have a clay tile roof. Do I have to remove a row of tiles to nail in the drip edge, or can the drip edge be nailed into the fascia? I am also wondering if you are supposed to install a band of some sort of underlayment on the roof edge of the drip edge. (I am really trying to avoid removing a row of clay tile–that would be pretty hard). If the clay tile overhangs the roof by an inch, do I even need a drip edge or can I go with just gutters?
Rachel Lynn says
Kimberly, I am not as confident in my knowledge on tile roofs. I’ve only done a few repairs on these. But, I believe most areas are now requiring a drip edge with new installations. If I were doing a repair and got the request that you are making, I would recommend the client get high-back gutters. Google “high-back gutters” and you will see that the design will give you two-for-one protection.
Kimberly Siegel says
Thanks!
Steve Seckar says
Thank you for this article. It was very helpful in diagnosing a problem I’m having. I’m interested in your advice for a solution. I believe I have water getting behind the drip edge in the corner of a valley of my roof. The drip edges look to have been cut to abut vs. overlap as you recommend. Since the shingles in the corner of the valley do not “fold” into a perfect angle at the corner, there is a gap here between the shingle and the drip edge. Surface tension of the water during rains causes the water to be sucked into this gap. Photos are here for a visual. https://photos.app.goo.gl/zXN41MR5YXdPiVmG6. Accordingly, water has rotted out the fascia below this valley. Prior to replacing the fascia, I need to plug this gap. I’m thinking either spraying a bit of expandable foam into the gap and/or just filling the gap with silicone caulking so the water can not get sucked in. Would you have another approach to simply solving this problem (other than remove the gutter and redo the drip edge, which I’d rather not take on). Thanks for any wisdom you can provide.
Rachel Lynn says
Yes, it looks like the edges are not overlapped from what I can see, and the cut made on the right side of the image is not clean. That jagged gap will allow water to funnel in by the gallons. For now, I would plug that hole with silicone to prevent further damage until you can do a proper fix. When you can, have that valley repaired so that the drip edge is correct. You may also want to check your shingle overhang. It appears that they failed to leave enough. However, images can be deceiving and I may be miss reading the photo. For a complete and solid repair, have the lower 3rd of the valley shingles removed. This way you can inspect the damage and see if the waterproofing membrane (or flashing) is still intact. Then, replace that portion of your drip edge (at least 12″ along each side) using the correct cuts and folds. Replace/repair valley as needed. Best of luck!
Gregory says
I just wanted to say thank you for the article on installing drip edge. I am a new homeowner and it has been really helpful. A few days ago, my brother-in-law came over to help me install my drip edge and noticed that we were doing it wrong! He said that we need to use a soffit board instead of flashing as the sealant and then attach the sealant to an eave or fascia board with screws or nails. This is great advice! Thanks again for your expertise in this field. It is very much appreciated!
Janelle says
First off, I love seeing a woman who is great at construction! What a great article/ website. I greatly admire you. I found this article looking for how to replace a few strips of drip edge blown down in a Louisiana hurricane. My roof is relatively new from a previous hurricane. I am now concerned because what you said about the drip edge needing to be installed off of, not flush with, the fascia, as mine is! However, I’m wondering if it makes a difference that the entire fascia (aside from a gable in front of the house where there is no fascia) has a vinyl covering, as do the soffits.The shingles also hang a good bit over the edge.
Rachel Lynn says
Janelle, thanks for your kind words.
Being that you are in Louisiana, vinyl coverings are a good thing. Although it is usually still best to have the drip edge pulled away from the fascia, the vinyl should provide protection from any water that rolls back. (of course, we are assuming a proper install of vinyl). The roofer probably installed the drip edge slightly away from the facia, but after the vinyl was installed that gap was reduced. It is also possible that your township requires the install as is. I have found that high-wind areas often have requirements that are different than the norm. If you feel that it may be a problem, you could check with your local code to see if everything is as it should be.
Sara says
Hi, I am putting drip edge on eaves side only, under existing asphalt shingles. I can slide the drip edge under, but can’t get it far enough under so that the shingles extend over the top flange. That is, the flat (horizontal) edge of the drip edge extends past the edge of the asphalt shingles. Will this wick water under shingles? (Capillary action)? Thank you
Rachel Lynn says
Sara, one of two things are happening. Either the roof shingles do not have enough overhang (i.e you can get the drip edge to go all the way back but still not have the shingles hang over) or you are encountering the nails located in the starter course. Without seeing what is going on, I can only guess that it is the second issue. The starter course nails are usually lower down than a standard run of shingles. You need to carefully remove those nails in order to get the drip edge to slip completely under. You can use a roof snake to make your job less likely to result in damage to the shingles. Be sure to replace the nails with new ones.
ROBERT J KAMPER says
We just had our roof shingles replaced after hail storm damage. Our gutters have a foam insert for vermin exclusion, and my wife was concerned that parts of the foam appeared to be sticking up and pushing up the shingles.
On inspection. it appeared that about two feet of the edge of the roof had no drip edge at all. The foreman of the crew told us that it was because the house had an original trim, so they didn’t cover it. He said that they did that all the time. I am not convinced that he was telling the truth, the whole truth, and nothing but the truth. Are there any building or construction inspectors who could give me an objective assessment? How would I contact or find them? Thanks in advance for your time and consideration.
Rachel Lynn says
You could have the city inspector come out and give you his opinion.(i.e Is it done to code?). That is good when you want to make the contractors re-do part of a job. Another great option is to signup and ask for recommendations on Nextdoor.com You should find a lot of people in your city/town who can recommend a local expert. Keep in mind that Nextdoor usually requires proof that you reside in a particular area. It’s been a while, but they used to just mail out a postcard with a code to your address. You use that code to finalize your account. It’s free and lets you can keep up with just about anything going on in your area – from events to crime, and so-on.
MG says
I appreciate your post more than you can imagine! This was a new aspect for me that needed to be addressed and you gave me such comprehensive and clear information! I am delighted to have found this page! Keep up the great work and have a wonderful life!
Joshua says
Hi, this is partly related. I’m building a plywood deck with a drip-edge flashing and fascia mounted railing posts. Do I mount the posts over the flashing or do I cut the flashing to fit between each 4×4 post? and then add some sort of caulk between the post and the fascia?
Thanks in advance.
Rachel Lynn says
I would mount over it to create a seamless barrier. There would be too many places for future water penetration if you cut the flashing.
Jeremy L. says
Rachel,
I’m a construction inspector in a hurricane-prone area and came to read this post assuming it would be full of errors and half-truths. The majority of contractors that I see get drip edge installation wrong.
I was pleasantly surprised! Your post is clear, concise and informative. All of the information provided lines up exactly with International Residential Code requirements and you taught me a few things.
Keep up the good work!
Rachel Lynn says
Jeremy, Thanks for stopping by. Now that I have earned a little trust, I hope you’ll stop by again. ;-)
Robert Henson says
We have gutters installed on 2nd roof shingles without drip edge. Now we have to get new roof with drip edge. Can that be done without removing gutters.
Thank you for excellent article. God bless you.
Rachel Lynn says
Robert, absolutely! They may need to unscrew the gutter hanging bolts as they go to prevent the need to make relief cuts to the drip edge, but it can be done. The second alternative would be to cut around the hangers, but I prefer to not do it that way.
John Robertson says
Hey Rachel,
Excellent article. I am having a new asphalt shingle roof installed and will be adding drip edge or gutter apron. After the roof is complete, I will have gutters installed with gutter guards. The gutter company offers three styles of gutter guards to accommodate differing situations – fascia-mount chassis, short-back chassis and under-shingle chassis. You can view pictures and descriptions here:
What would be the best practice for integrating the drip edge with the gutter guard?
Rachel Lynn says
I am not familiar with One Gutter. However, the style of gutter guards really depends largely on the slope of the roof and what environmental issues you will deal with. For example, pine needles can quickly clog a mesh guard that is too open. As such, you would want to go with a finer mesh. But too fine a mesh doesn’t work as well on steep slopes. That’s just a few examples, but in the nut shell, your situation would have to be assessed individually.
Alonzo says
Hi, I have a quote for installing drip edge that includes removing and reinstalling the gutters. Is that typically required if your just installing drip edge?
Also, is it best practice to have IWS extend down the fascia board a bit (behind the gutters)?
Rachel Lynn says
Alonzo, it depends on the type of gutters, if they need to be adjusted lower/higher, etc. There could be issues that they are dealing with. It’s hard to say without seeing them, but normally the drip edge should be able to be installed and hang into the gutter without the need to remove them.
Monte says
I recently had an asphalt shingle roof installed. The roofer told me drip edge was unnecessary because I had gutters. I called the local building department and they said it has to have drip edge to meet code. When I told him this he said he was going to come back and remove the gutters and install the drip edge. He came and installed it over the gutters. I can see in my attic where the drip edge is not attached to the decking or is that normal?
Rachel Lynn says
It should be attached to the roof decking with roofing nails.
R J says
Your article is very clear and well written but it does not address the case of a roof that slopes in one direction only. The rake at the 2 sides and drip at the lower edge are addressed but I am not clear in the best way to address the high ends “drip-edge” or the 3-tab shingles. Do you have any recommendations ?
Rachel Lynn says
I believe you are referring to a scallion roof (or shed roof). On these types of roofs, the high side is the top eave and the low side is the bottom eave. The sides that connect the two are the rakes. Apply the drip edge using the same directions I gave above.