Does Drip Edge Go Under or Over Underlayment?
Does Drip Edge Go Under or Over Underlayment? The correct answer is that drip edge typically goes over the underlayment at the eaves (lower edge of the roof) and under the underlayment along the rake edges (sides of the roof). This ensures proper water shedding and protects the underlying roof structure.
Understanding the Basics: Why Drip Edge Matters
The unsung hero of a roofing system, drip edge, plays a crucial role in preventing water damage. It’s a metal flashing installed along the edges of the roof, directing water away from the fascia board and roof sheathing. Without it, water can wick back under the shingles, leading to rot, mold, and costly repairs. Knowing Does Drip Edge Go Under or Over Underlayment? is essential for a properly functioning roof.
Benefits of Correct Drip Edge Installation
Proper drip edge installation offers several key advantages:
- Water Diversion: Prevents water from running down the fascia and siding, protecting against water damage.
- Protection Against Rot: Prevents water from saturating the roof decking and causing rot.
- Erosion Control: Helps prevent soil erosion around the foundation by channeling water away.
- Improved Aesthetics: Creates a clean, finished look for the roof edge.
- Ice Dam Prevention: Can help reduce the formation of ice dams in colder climates.
The Correct Installation Process: Eaves vs. Rakes
The answer to the question Does Drip Edge Go Under or Over Underlayment? depends on whether you’re working along the eaves (lower edge) or the rakes (sides) of the roof.
Eaves:
- Install the drip edge over the underlayment.
- Overlap the drip edge sections by at least 2 inches.
- Fasten the drip edge securely to the roof decking with roofing nails.
- Ensure the drip edge extends slightly over the fascia board.
Rakes:
- Install the drip edge under the underlayment.
- Overlap the drip edge sections by at least 2 inches.
- Fasten the drip edge securely to the roof decking with roofing nails.
This two-part approach ensures that water flows correctly off the roof and is properly diverted away from the building.
Common Mistakes to Avoid
- Installing drip edge backward: The bottom flange must point outward and downward.
- Using the wrong type of drip edge: Different styles are available for different applications.
- Insufficient overlap: Failing to overlap the drip edge sections properly can create weak points where water can penetrate.
- Incorrect nailing: Using too few nails or placing them improperly can compromise the drip edge’s effectiveness.
- Ignoring building codes: Always check local building codes for specific requirements.
- Not understanding whether Does Drip Edge Go Under or Over Underlayment? based on location (eaves vs. rakes).
Types of Drip Edge
| Type of Drip Edge | Description | Common Use |
|---|---|---|
| Type C | Features a wide flange and a hemmed edge for added strength. | Most common type, suitable for various roofs. |
| Type D | Similar to Type C but with a narrower flange. | Less common, used when space is limited. |
| Gutter Apron | Designed to integrate with gutters, directing water directly into them. | Roofs with gutter systems. |
Why the Order Matters
The order in which the drip edge and underlayment are installed is crucial for proper water management. Installing the drip edge over the underlayment at the eaves ensures that water flows over the underlayment and directly off the roof. Along the rakes, installing the drip edge under the underlayment allows any water that gets under the shingles to flow onto the underlayment and then off the roof via the drip edge. This layering provides multiple layers of protection against water intrusion.
Frequently Asked Questions
What happens if I install drip edge incorrectly?
Incorrect drip edge installation can lead to water damage to the fascia board, roof sheathing, and even the interior of your home. This can result in rot, mold growth, and costly repairs. Furthermore, improperly installed drip edge might void manufacturer warranties on your roofing materials.
Can I install drip edge myself, or should I hire a professional?
While some homeowners with experience in roofing can install drip edge themselves, it’s generally recommended to hire a professional. They have the knowledge and experience to ensure the job is done correctly and according to local building codes. Knowing Does Drip Edge Go Under or Over Underlayment? is just one aspect; proper installation requires skill.
What type of drip edge should I use?
The best type of drip edge depends on your specific roofing system and local building codes. Type C drip edge is the most common and versatile option. Consult with a roofing professional to determine the best choice for your needs.
How much overlap should I use when installing drip edge?
A minimum overlap of 2 inches is recommended for drip edge sections. This ensures a watertight seal and prevents water from seeping through the joints. In areas with heavy rainfall, a greater overlap may be necessary.
What kind of nails should I use to install drip edge?
Use roofing nails with a diameter of at least 11 gauge and a length sufficient to penetrate the roof decking. The nails should also be corrosion-resistant to prevent rust and staining.
Do I need to remove old drip edge before installing new shingles?
Yes, old drip edge should always be removed and replaced when installing new shingles. This ensures a fresh, watertight seal and maximizes the lifespan of your new roofing system.
Does drip edge help prevent ice dams?
While drip edge alone won’t prevent ice dams, it can help reduce their formation by directing water away from the edge of the roof. However, proper attic ventilation and insulation are also crucial for preventing ice dams.
What is the cost of installing drip edge?
The cost of drip edge installation varies depending on the size of the roof, the type of drip edge used, and labor costs. On average, expect to pay between $1.50 and $3.00 per linear foot for professional installation.
Is drip edge required by building code?
In many areas, drip edge is required by building code. Check with your local building department to determine the specific requirements in your area.
Can I paint drip edge to match my house?
Yes, you can paint drip edge to match your house. Use a primer specifically designed for metal and a high-quality exterior paint. However, be aware that painting drip edge may require periodic touch-ups.
How do I inspect my drip edge for damage?
Inspect your drip edge at least once a year for signs of damage, such as rust, dents, or loose nails. Pay close attention to areas where the drip edge overlaps or meets other roofing components.
What if my roof doesn’t have drip edge?
If your roof doesn’t have drip edge, it’s highly recommended to have it installed as soon as possible. This will help protect your roof from water damage and extend its lifespan. Consult with a roofing professional to get a quote for installation. Understanding Does Drip Edge Go Under or Over Underlayment? is the first step to correcting this deficiency.