Roof Slopes and Roofing Products 

The type of material you put on your roof to keep the elements at bay depends on the slope of your roof. The most common from of roofing in America is the asphalt shingle. However, even if your home has asphalt roofing, there may be portions of your home that require a low-slope membrane to adequately keep out moisture.

Determining Slope

Slope is measured in units of rise over run in inches. You may see something like 4/12 or 10/12. These are the number of inches a roof rises over 12 inches. The larger the first number, the steeper the slope of the roof.

Where Shingles Can Be Used

Standard asphalt shingle installation works for slopes from 4/12 up to 18/12. Most manufactures of asphalt shingles will allow for them to be applied over 2/12 and 3/12 slopes if a water proof underlayment (called Ice and Water Shield) is applied under the entire area.

What If I have a Low Slope or Flat Roof?

There are a few different options for flat or low slope roofing situations. The product you choose will depend on your need.

1. EPDM

Ethylene propylene diene terpolymer (EPDM) is a very durable roofing membrane that is made of synthetic rubber.

EPDM roofing on a front Porch

2. TPO

Thermoplastic polyolefin (TPO) is a membrane that is “heat weldable…Heat welds provide a monolithic seam that prevents water intrusion. Both are considered “cool” as a result.” Check out Firestone’s website for more information.

3. Multi-Ply Asphalt

This product is composed of a base sheet and a cap sheet that weld together through heat and sealants. The surface is similar to a shingle in that it is covered with ceramic granules. It typically comes in a 3’ wide roll. This product is used most often when ascetics are important as the color of the cap sheet can match the shingle product

Before and After of a multi-ply low-slope roofing membrane

If you have any questions about these or other roofing products, request a quote, or give us a call. We are here to serve you!

Amber Valley Construction