The roof of your house might make up to 40% of the exterior of your house. It’s critical to understand what keeps your home looking good and dry, from curb appeal to home safety. The majority of homeowners will have to repair their roof at some point, but many are wondering where to begin. That’s why, before initiating any roofing job, it’s important to understand the most common roofing terms and components.

7 Basic Roofing Components you should be familiar with. 

• Shingles: These can be composed of a variety of materials, but its main purpose is to keep the weather off of the underlying sheathing. Traditionally, shingles are measured in squares.
• Sheathing: Attached to the rafters that roof your home are boards or sheet material. The deck of a roof is another name for it.
• Trim: Installed to protect the seam in the roof along a hip or ridge (see more on hips and ridges below). 
• Rafters: These are the wood or metal slats inside your home that support the sheathing and shingles. They’re a bit like the skeleton for your roof.
• Underlayment: Water-resistant, paper-like material that is laid over plywood sheathing to seal it from damaging elements such as rain and snow. This is used with a membrane and vapor barrier, which is typically a sheet of plastic blocking air and water from permeating through. 
• Flashing: Sheet metal or other material installed on top of the joints of a roof system to prevent water damage. The joints of your roof are anywhere it changes direction, and flashing is used to help seal these points off from the elements. 
• Drainage: The design feature of a roof that allows it to shed water. This is measured using the slope, or pitch, of the roof, which is determined by the rise in inches for each foot of horizontal distance—known as the “run.” For example, a roof with a 5-in-12 slope rises 5 inches for every foot in distance. 

Roof Design Elements

1. Gable Wall: These are triangular portions of the home which extend from the eaves to the peak of the roof. 
2. Centerline of Ridge: Also called the verge, this refers to the wall or rafter under the edge of a roof where a gable ends. 
3. Ridge: This is the highest point of the roof, which is also referred to as the peak. 
4. Valley: The areas of the roof where two sections meet and slope down. 
5. Eaves: Edges of the roof that hang over the exterior walls of a home. 
6. Hip: A high point where two sections of the roof meet. 
7. Abutment: Where sections of the roof meet a vertical area such as a wall or chimney.
8. Dormers: Not every roof has them, but these are sections of the home that stick out from the roof, designed to bring in natural light to an attic or third floor. 

Take a look outside and check which elements your roof has, noting how many ridges, hips, abutments and gables are present. If you’re considering a roof replacement in the near future, it’s important to understand the square footage and design of your existing structure to estimate how much it will cost.