Can you shingle a flat roof? This is a common question asked by homeowners with flat roofs. The direct answer to it is you should never put shingles on a flat roof. Here’s why.
1. The Minimum Pitch for Shingles
Shingles need to have a slope to function correctly. This has to do with the way shingles are installed. Shingles overlap from the eaves to the peak, where the final layer of shingles is overlapped by a roof cap.
The pitch is defined by the rise-over-run ratio. This means if a roof slope rises 5 inches when measured along the bottom of a horizontal roof truss, the slope is said to be 5/12.
As a good rule of thumb, roofs with a pitch of 2/12 and greater are able to have shingles. However, 2:12 roofs are more susceptible to failure than the steeper slopes.
Flat or low-slope roofs are better to be covered with PVC, TPO, EPDM, modified bitumen, metal, or other flat roofing materials.
2. Susceptibility to Leaks and Ice Dams
The challenge with flat roofs is simple. Gravity. When shingles are installed on a flat roof, water drains very slowly, increasing the risk of water leaking through and around the shingle overlaps. Improper drainage can cause the roof to develop leaks and become weak over time.
Winter can create a challenging problem as snow thaws and travels underneath the shingles. Temperature fluctuation and poor roof ventilation can cause ice dams to form as snow melts.
As the melting and freezing cycle repeats, the water quickly ends up underneath the shingles and into the living space.
3. Extra Maintenance Needs
Flat roofs generally require more maintenance than pitched roofs. Because of the low slope, extra care is also needed to ensure water or debris drain from the roof. Frequent maintenance means a low slope roof gets a lot of foot traffic. If shingles are protecting the roof, the mineral granules embedded on the shingle surface will cause them to break down faster.
To learn more about low slope roofing solutions, contact Pinnacle Roofing today. Our expert roofing contractors can help you choose the best roofing material for your roof and provide high-quality installation, replacement, repair, or maintenance services. We proudly service the Capital Region of New York and Southern Vermont.