When installing a roof, the order of the drip edge and tar paper—also called roofing felt or underlayment—depends on where the metal is placed. For a typical asphalt-shingle roof, the drip edge goes under the underlayment at the eaves and over the underlayment at the rakes. This arrangement helps direct water off the roof and into the gutters while protecting the roof edges. Local building codes and product instructions can vary, so both should be checked before work begins.
Quick Answer: Drip Edge Over or Under Tar Paper?
For a standard asphalt-shingle installation, the common sequence is:
- At the eaves: Install the drip edge first, then lap the underlayment over its roof-facing flange.
- At the rakes: Install the underlayment first, then place the drip edge over it.
The eaves are the lower edges of a sloped roof, where water typically runs toward the gutters. The rakes are the sloping edges along the roof’s gable ends. Because water moves differently at these locations, the layers are arranged differently. The roof covering and flashing should form a continuous path that sheds water outward rather than allowing it behind the metal.
Why the Installation Order Changes by Roof Edge
At the eaves, the drip edge goes under the underlayment
At the eaves, water travels down the roof toward the gutter. Installing the drip edge first lets the underlayment overlap the metal’s upper flange. Water that passes through or beneath shingles can then run from the underlayment onto the drip edge and away from the roof deck.
If the underlayment is installed beneath the eave drip edge instead, water can meet the exposed edge of the underlayment and potentially work underneath it. That can wet the roof sheathing, fascia, or other materials. The correct overlap helps maintain a downward-draining path into the gutter area.
At the rakes, the drip edge goes over the underlayment
At a rake, wind-driven rain can travel across the roof surface toward the sloped edge. Placing the rake drip edge over the underlayment covers the underlayment’s exposed edge and helps shield it from water and wind. The metal edge also gives water a route off the roof rather than behind the roofing layers.
These are general rules for typical asphalt-shingle roofs, not a substitute for project-specific instructions. Roof shape, underlayment type, climate, and flashing details can affect the assembly. A roofing manufacturer’s instructions and the locally adopted building code should take priority when they specify a different method.
Typical Layer Order for Asphalt Shingles
The following table shows the usual sequence at each roof edge. It describes the relationship among the roof deck, drip edge, underlayment, and shingles—not every detail of a complete roof assembly.
| Roof location | Typical order, from roof deck outward | Purpose |
|---|---|---|
| Eave | Roof deck → drip edge → underlayment → shingles | Lets underlayment drain over the metal and toward the gutter. |
| Rake | Roof deck → underlayment → drip edge → shingles | Covers the underlayment edge and helps shed water at the gable edge. |
Some roof details include additional components, such as an ice barrier, a starter strip, or specialized flashing. Those layers must be integrated according to the applicable code and product instructions. The table is a guide to the usual drip-edge and underlayment relationship, not a complete installation specification.
What Building Codes and Instructions Say
Many U.S. residential building codes address drip edge and asphalt-shingle underlayment. For example, versions of the International Residential Code include provisions for drip edge at eaves and gable rakes and specify how underlayment relates to the drip edge. The exact wording and requirements depend on the code edition adopted by the local jurisdiction, along with any local amendments.
Roofing products also have installation instructions. Shingle manufacturers may specify underlayment laps, starter-strip placement, fasteners, and how the roof-edge metal should be integrated. Those details matter: a roof can use the familiar eave-and-rake sequence yet still be installed incorrectly if laps, fasteners, or flashing are misplaced.
Before starting, a contractor or property owner should check:
- The locally adopted residential or building code and any local amendments.
- The shingle manufacturer’s current installation instructions.
- The underlayment and drip-edge manufacturers’ instructions.
- Permit requirements, if the project requires a permit or inspection.
Where instructions conflict or a roof has unusual details, the local building department or a qualified roofing professional can help determine the applicable assembly.
How to Install Drip Edge and Underlayment
Roofing work involves fall and tool hazards. Work should be performed from properly set up ladders or scaffolding, with appropriate fall protection. Wet, icy, steep, or windy roof conditions can make the work especially dangerous. The following overview explains the sequence; it is not a replacement for manufacturer instructions or safe-work practices.
Prepare the roof edges
Inspect the roof deck and edge framing before covering them. Replace damaged or rotten sheathing, and make sure the roof edge is sound and ready to receive the metal. Remove debris and verify that the gutter area is positioned to catch roof runoff. Drip edge cannot correct a deteriorated deck or an improperly installed gutter.
Install the eave drip edge
At the lower roof edge, position the drip edge over the roof deck edge in accordance with the product instructions and code. Fasten it using the specified type and spacing of fasteners. Install the underlayment afterward so that its lower edge laps over the drip edge’s upper flange. This creates the intended drainage path toward the metal edge and gutter.
Install underlayment and rake drip edge
Lay underlayment across the roof deck, following the specified course direction and overlap dimensions. At the rake, the underlayment typically extends to the roof edge beneath the metal. Install the rake drip edge over that underlayment edge, fastening it as directed. Where metal pieces meet, use the required overlap and avoid joints that create an uphill-facing opening for water.
Complete the shingle edge details
Install shingles, starter material, and other components in the sequence specified by the roofing manufacturer. The shingles should cover the appropriate portion of the drip edge without obstructing the gutter or violating installation requirements. Avoid exposed fasteners or cuts that leave water paths into the deck. A professional should verify edge details before they are concealed by later courses.
Drip Edge, Tar Paper, and Underlayment Terminology
Tar paper is a common informal name for asphalt-saturated roofing felt. Modern roofs may instead use synthetic underlayment or a self-adhered membrane. These products all serve as secondary water-shedding layers beneath the roof covering, but their handling and installation requirements are not identical.
Drip edge is formed metal flashing installed along roof edges. Its profile helps direct water away from the roof deck and fascia. It is often made from corrosion-resistant metal, but the required material, dimensions, and fastening method depend on the project and applicable code.
Underlayment lies between the roof deck and the shingles or other roof covering. It offers secondary protection if water gets beneath the primary covering, but it is not a substitute for correctly installed shingles, flashing, or roof-edge metal. Calling a product “tar paper” does not mean its manufacturer’s installation directions can be ignored.
Common Installation Mistakes
- Using the same sequence everywhere: The usual asphalt-shingle detail differs at eaves and rakes. Reversing the laps can expose an edge to water.
- Leaving underlayment exposed at the rake: Rake drip edge typically covers the underlayment edge to protect it from water and wind.
- Putting the eave underlayment beneath the metal: At a typical eave, the underlayment laps over the drip edge so runoff can move outward.
- Skipping the drip edge: Roof-edge metal helps protect the deck and direct runoff. Whether and how it is required depends on code and the roof assembly.
- Using the wrong fasteners or spacing: Fastener type and placement should match the metal manufacturer’s instructions and local requirements.
- Creating gaps or uphill laps: Poorly overlapped metal can create openings where water enters instead of shedding off the roof.
- Assuming edge metal fixes drainage problems: A drip edge cannot compensate for a poorly placed gutter, incorrect roof slope, damaged fascia, or defective shingles.
Do Ice-and-Water Barriers Change the Order?
In cold regions, code or design requirements may call for an ice barrier near eaves. A self-adhered membrane may be installed over the roof deck and integrated with the drip edge and underlayment. The precise sequence can depend on the membrane’s instructions, the roof design, and local requirements. It should not be assumed that every membrane is installed in the same position or with the same laps.
Ice barriers are intended to help limit water intrusion associated with ice dams, but they do not prevent every ice dam or repair ventilation, insulation, or drainage problems. When a roof includes an ice barrier, the full edge detail should be checked against the applicable code and product instructions before the work begins.
How to Check an Existing Roof
From the ground, a homeowner may be able to see whether metal edging is present, but the layering beneath shingles and underlayment usually cannot be confirmed without lifting or removing roofing materials. Signs such as water staining at the fascia, peeling paint, wet sheathing, or recurring leaks near the roof edge deserve professional inspection. They do not, by themselves, prove that the drip edge was installed in the wrong order.
Before a reroof, ask the contractor how the eave and rake details will be handled, which underlayment and drip edge will be used, and which code and manufacturer instructions apply. A written scope can clarify whether existing edge metal will be reused or replaced and how it will connect with gutters, fascia, valleys, and other flashing.
Key Takeaway
For a typical U.S. asphalt-shingle roof, the standard answer to “drip edge over or under tar paper” is under the underlayment at the eaves and over the underlayment at the rakes. The eave detail directs runoff over the metal toward the gutter, while the rake detail covers the underlayment edge. Local code, roof design, and product instructions determine the final installation requirements.