Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
While doing any roof work, it’s important that everything is layered so water drains off properly. The placement of the drip edge is critical to help prevent rotting due to water damage. Where do you install drip edge in relation to the underfelt paper?
If the drip edge is along the eaves of the roof, it goes underneath the felt underlayment. When the drip edge is along the rake edges, it is placed over the felt paper underlayment.
If you are not a professional, do not fret, as it isn’t too hard to grasp. Discover what the purpose of drip edge and felt paper is and why you place the drip edge over or under felt paper. I’ll also explain the differences between eaves and rake edges.
Why Does Drip Edge Go Underneath the Felt Paper on the Eaves of the Roof?
When you install the drip edge under the felt paper along the eaves of the roof, this will allow water to flow freely over the drip edge. Whenever you are dealing with a roof, it is imperative that you always keep in mind the direction or path water will run along and off the roof.
If the drip edge was installed over the felt paper or and underlayment, water may puddle up against the drip edge. Over time some water may work its way under the drip edge and get onto the wood underneath. This will cause your roof to start rotting, so be sure to place the drip edge underneath the felt paper on the eaves of the roof.
Why Does Drip Edge Go Over The Felt Paper On The Rake Edges Of The Roof?
On the rake edge of the roof, the drip edge goes over the felt paper so it will seal the edges of the roof. By doing this, the drip edge will protect the would-be exposed side of the roof from windblown rain.
Without the drip edge on the rake edge, the underlayment and wood decking would be exposed to the elements. On top of rotting, this exposure will also cause your roof to leak.
As a reminder to any DIYer, do research before doing any work to see if there are any permits that might be required before you begin working.
What Is The Purpose Of Drip Edge?
Drip edge plays an important in extending the life of your roof. This includes:
- Keeps rain from blowing into the wood decking, which will cause rotting over time.
- Sends water that is running off the roof away from the fascia board and away from the building.
- Prevents insects and other pests from penetrating the edges of the roof.
- Keep gaps from forming at the bottom of the roof.
- It can act in place of gutters to direct runoff water away from the building.
- When a home has gutters, it helps direct water from the roof into the gutters.
- Drip edge helps to protect the roof from forming leaks over time by protecting the roof from wind and water exposure.
- The extended protection that drip edge provides to your roof means fewer repairs and a longer life for your roof.
Three Types of Drip Edge
- Standard 90 Degree Drip Edge. This is also referred to as Type C or L-Style Drip Edge. As the name suggests, this is the common type of drip edge and is in an L-shape at a 90-degree angle. This works perfectly for most standard roofing jobs. It is also the most affordable type and works great with gutters. This type of drip edge costs, on average, about $0.49 – $0.79 per foot.
- T-Style, or Type D Drip Edge. This style of drip edge is an older and style and not used much anymore. T-Style Drip Edge is designed to carry water away from the home and doesn’t require gutters. As a matter of fact, this is not the type of drip edge you would use if you do have gutters. This would be good for smaller roofs that don’t need gutters, such as sheds and storage buildings. This type of drip edge costs, on average, about $0.60 – $0.89 per foot.
- Type F, or Gutter Apron, or Wide Faced Drip Edge. This type of drip edge is similar to standard 90-degree drip edge, except it has a wider face that extends past the 2- inch requirement. For that reason, this is the perfect choice for repairs over an existing standard 90-degree drip edge. This type of drip edge costs, on average, about $1.30 – $1.60 per foot.
What is the Purpose of Felt Paper?
Felt paper is designed to protect the wooden decking of the roof from the elements and prevent rotting and leaks that water and wind can cause over time. Felt paper is also called roofing felt underlayment, roll roofing, or roofing tar paper. It is typically made from a combination of asphalt and either paper or rags and is installed over the wooden decking and under the shingles.
If you are repairing a roof, you can apply a primer that will allow you to properly install new felt paper over the old felt paper. In most cases, though, you will want to remove the old felt paper and lay down new felt paper. If you are having to replace any or all of the roof boards, you will have to lay down new felt paper. Felt paper usually will cost right around $4.00 per square foot for basic quality felt paper. Premium quality felt paper will run you about $5.55 per square foot.
What are the Differences Between Eaves and Rake Edges?
If you are a DIYer, you may not be familiar with all the lingo with roofing. To help out, we are going to take a little time and explain some terms you might not be familiar with. If you don’t need this quick tutorial, you can skip on to the next section.
- The eaves of a roof are the part of the roof that overhangs the outside walls of the home at the bottom part of the roof. This provides an area where water can run off of the roof clear of the building itself.
- The rake edge of a roof is the slanting edge on the end wall of the house. Rake edges extend from the top of the roof down to the eaves of the roof. There may or may not be an overhang on the rake edge of the roof.
- The fascia is the decorative board that extends down from the roof edge. This can be on either the eaves or rake edge of the roof.
- Felt paper is made of a combination of asphalt and either paper or rags. This paper is applied underneath the shingles and over the wooden decking of the roof to protect the wood from the elements and prevent rotting and leaks.
Conclusion
If the drip edge is going on to the eaves of the roof, you would position it under the felt paper. When the drip edge is being installed along the rake edges, it would be placed over the drip edge. This is done to ensure water runs off the roof smoothly and to protect the decking from exposure to the elements. When installing drip edge, make sure you get right the type for the job you are doing. As always, be safe and use proper precautions.
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