Roofing 101

The following are some common roofing terms used throughout the industry to describe the various components of your roofing system.  

We publish this information in an effort to inform and educate our customers.  

The Deck

The deck is your roof's foundation and usually consists of either plywood or roof board.  Also known as "sheathing", the deck provides the surface for all roofing materials to be adhered.  

Ice & Water Shield

A modified bitumen membrane designed to provide protection for the roof deck. Ice & water shield should be installed at a minimum of 3-feet above the eaves and under all valleys.  Depending on the pitch of your roof, you can go as high as 6-feet up from the eaves.  


Also known as "felt" or "paper", underlayment provides another layer of protection for your roof, and is designed to cover the balance of the deck after the ice & water shield.  Driving rains often result in water backing up under the shingles, so it's important to have added protection to avoid leaks and wood rot. 

Drip Edge

Drip edge are thin pieces of metal that run the perimeter of the roof and are designed to guide water more easily into the eavestroughs.  These strips of metal are installed under the ice & water shield and, while not mandatory, aid greatly in prolonging the life of your roof. 


Shingles are NOT waterproof - they are designed to shed water away from the roof and into the eavestroughs.  Maximizing the life and performance of your shingles requires all other components of the roofing system to be functioning properly.

There are numerous varieties of shingles on the market today, the most common being asphalt. There are many grades of asphalt shingles available in addition to more premium options, such as cedar and slate. 


Flashing is found where roof planes intersect, around chimneys, against walls and skylights.  Flashings are the most common areas where leaks occur and are one of the primary components of the roofing system that animals love to pick at.   


Ventilation is the most important component of your roofing system and is divided into two separate areas - intake and exhaust.  Ensuring an adequate number of vented soffit panels allows fresh air in to circulate through the attic and let the roof breathe, while warm, moist air is expelled through exhaust vents on the roof.  Proper ventilation also aids in reducing heating and cooling costs.


Valleys are found where two slopes of a roof meet and are designed to provide an easy path for water to flow down and drain into the eavestroughs.  Commonly made of pre-pained sheet metal, valleys are key in adequate drainage but are also areas where snow and ice can build up,  so it's imperative that an ice & water membrane is installed under every valley.  

Eavestroughs & Downspouts

Eavestroughs collect water shed from the roof and give it a path towards the downspouts for drainage.  Commonly made of aluminum, but also available in more premium materials, the eavestroughs surround the perimeter of the roof and are sloped for positive drainage.  Depending on the size and shape of your roof, you may require additional downspouts to avoid pooling and overflowing in the eaves, or fewer downspouts based on the slope of the troughs themselves.