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The 8 Main Roof Components Explained

Aug 4, 2022 | Blog, Roof Replacement

A brief explanation of roofs to make navigating your roof replacement easier…

There are eight components to every roof. Some of them are the same but many of them come in different quality levels, or aren’t used to the proper extent. This article will help you know what to look for when navigating estimates from different roofers.

roof decking

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Decking comes in several different options but in short it’s the wooden surface everything else gets attached to. It’s important that it be checked and, if needed, replaced. You don’t want your decking aging out before the rest of your roof.

The good news is that with properly functioning roofs decking can last many decades. That being said, it’s not uncommon to need to replace a handful of 4’ x 8’ decking boards when replacing your roof.

Ice & Water Shield

Ice & Water Shield is a very important yet highly overlooked component. Over half of the calls we receive each February about leaks end up being because ice and water shield wasn’t installed with the roof.

What is it? It’s a three-foot tall roll of sticky backed asphalt material that acts as a last defense in areas that are most prone to leaks.

Where should it be used?

CODE in Central Indiana: Valleys only (find out more about whether your county requires additional ice and water protection here)


  • Gutter lines
  • Against walls where the roof meets the wall
  • Around roof penetrations (chimneys, pipes, etc.)

This is one of the most common items that is most likely missing from some of those inexpensive roof replacement estimates.

Drip Edge & Gutter Apron

Drip Edge & Gutter Apron are both pieces of metal that should be installed along the perimeter of the roof.

Gutter apron is a piece of metal that protects the boards the gutters are attached to from rotting. Not having it can lead to costly rotting damage over time.

Drip edge is installed on the roof perimeter wherever the gutter apron is not installed. It makes sure that water coming off the roof doesn’t get behind the siding of your house. Again, it takes time but can be costly if not installed.

It is code to have both of these nowadays, though some roofers don’t include them. Make sure these are included in your estimate.

roof underlayment Noblesville, IN


Underlayment is a thin, protective barrier underneath the shingles. While you may still see tar paper being used, nowadays most roofers use a synthetic product that is much more durable and considerably more water resistant.

The purpose of underlayment is to act a second line of defense to the shingles. If for any reason, the shingles don’t do their job, the underlayment steps in and makes sure the water runs off the roof instead of getting into the house.


We all know what they are but this is likely the most significant area where apples start looking like oranges once you know what to look for.

There are three primary shingle types:


These shingles have a flat, non-dimensional look when installed. They have a lifespan of 15-20 years. These are typically a budget shingle because of their shorter lifespan and lower wind resistance rating.

red asphalt shingle roofing system Noblesville

You can typically expect to pay between $350-450 per 100 square feet for these in Central Indiana.

Architectural or Dimensional

These shingles appear to have dimension or layers, hence the name. They typically last about 30 years and have a wind resistance rating of 130MPH.

Today these are generally the standard choice for shingles, except in new housing developments, and you can expect to pay between $450-600 per 100 square feet.

Class 4

These can look just like architectural shingles but there are also options that have different sizes/shapes for a more unique look.

The BIG difference between Class 4 and architectural shingles is that they may have a higher wind resistance rating and have a higher impact rating, meaning that they are more flexible and less likely to be damaged by falling debris like hail. Some insurance companies even offer a discount for having them.

Because they are made of higher quality materials, they have an average lifespan of 40 years with warranties of around the same length.

You can expect to pay anywhere from $600-900 per 100 square feet for a roof with these shingles.


There are two primary ventilation choices in Indiana, but whichever you choose, know that roof ventilation (air flow inside the attic space) is one of the most important factors for making sure your roof doesn’t prematurely age. Improper ventilation can cut a shingle roof’s lifespan in half as well as cause mold or mildew issues inside the attic and drastically increase heating and cooling costs.

The two types of ventilation are Box Vents and Ridge Vents.

Box Vents

Box Vents are square boxes about 1’ x 1’ that you see in a line on the back of the house spaced about five feet apart.

Ridge Vents

Ridge Vents are harder to see because they blend by running the entire length of the top of the roof. These are a better option than box vents because they look nicer and create more even and consistent airflow throughout the entire attic. They are also more expensive.

Make sure you’re checking your estimates to see which one is being offered.

hip and ridge shingle Noblesville, IN

Hip & Ridge Shingles

These are shingles that go over the top of the roof. Some people refer to them as cap shingles because they go all the way on the top like a baseball cap.

They are designed to be able to bend on installation without being damaged and they also look much nicer than when 3-tab shingles are cut down in size and used instead. Class 4 shingles must be installed with specific hip and ridge shingles.

Starter Shingles

Starter shingles are specifically designed to go along the perimeter of your roof. They provide the features needed to provide high wind resistance and are typically required per manufacturers’ warranty guidelines. They can provide up to 10x the ice dam protection, so you definitely want them on your roof.

If you’re currently in the market for roof replacement and unsure of what these different roofing components are or why they’re important, be sure to ask your recommended roofer when they’re at the house. They should be able to answer any questions you have.