Why Does Roof Pitch Matter?

Apr 12, 2017

Why Does Roof Pitch Matter?

Roof pitch is important for determining the right roofing system and materials for your home, as well as how effective it will be at shedding debris and water from its ridges and seams. It can also be definitive in voiding warranties and whether a building permit will be necessary to complete that roofing project you’ve been thinking about.

The Differences Between Low & High Pitched Roofs

A low-pitched roof is anything that rises to 3 inches per horizontal foot or less. It is most commonly composed of three main elements:

  • A weatherproof layer: Using thermoset, thermoplastic, modified bitumen and a host of other weatherproof layers, the roof – no matter how flat – can be made to resist any weather condition and effectively deter water and storm debris.
  • Reinforcement fabrics: Made up of either woven glass, jute (Burlap) or mat glass, a roofing reinforcement fabric will give your weatherproof layer an added dimension of strength, horizontal alignment, longevity and resistance to sharp objects.
  • A surfacing material gives the preceding two layers a finer and/or smoother finish to top off the final look of your roof, adding more weatherproof properties and material reinforcement.

Steeper roofs (higher than 14 degrees) on the other hand, use materials and systems to keep any debris from collecting. A high slope roof is anything that rises more than 3 inches per horizontal foot. Because they ‘stick out’ when compared to flatter roofs, they must include roof coverings and materials to make your home weatherproof and nicer in appearance. And while more level roofs don’t need to be finished with a necessarily appealing look because they can’t be seen from the ground level, steeper roofs need to be more punctuated with a certain color and style of roofing because they can be seen more readily.

The three main components of steeper roofs are the following:

  • A roof deck is the entirety of the supporting system where the brunt of dead and live loads will be distributed. 
  • An underlayment is a sheet material designed to be placed as a barrier between the roof surface and the roof deck, acting as a secondary protective shield against the elements and preventing water leaks from forming in the future.
  • A covering – the material chosen to serve a certain aesthetic and protective role – consists of the most visible part of the roof such as shingle or tile forms of asphalt, ceramic, metal, concrete, and wood.

I’m Changing My Home’s Roof Pitch. Will I Need a Building Permit?

Any time you’re changing your home’s structural in any way, you will need to get a building permit for the final product not to violate local codes. So, yes, whether you’re making your roof pitch higher or lower, you will first need to receive approval for “New Construction and Renovation” from your city’s buildings department. If at first, you’re not sure, hire a roofing inspector to see what you’re going to change, he or she will also give pointers regarding the roofing project as a whole.

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