November 21, 2020
Minimum Roof Pitch for Shingles – Expert Advice from Sellers Roofing Company
Sellers Roofing Company has been on and off just about every known type of roof in the past 12 years. We take jobs ranging from minor repairs to large scale apartment communities and cover everything commercial and residential. Some of our hands have been roofing in excess of 20 years, and we consider ourselves to be one of the best roofing contractors in the industry. We wanted to answer the question: “What is the minimum roof pitch for shingles.” This question gets asked a lot, and we wanted to help out anyone new to roofing, and/or any do it yourself enthusiasts out there that may be thinking about taking on their own roofing job so that they can know the facts.
Keep reading to find out the minimum roof pitch for shingles, and a couple of other important facts you need to know about pitches and the requirements that need to be met for proper roof system performance and codes to be met.
Minimum Roof Pitch for Shingles
There are two main categories of sloped roofing: steep-slope and low-slope. Low slopes roofs are considered to be roofs with a lower pitch than 4:12, (four on twelve) and steep-slope roofs would be anything above a 4:12 up to a 12:12. (twelve on twelve.) The answer to this question is that the minimum roof pitch for shingles is 2:12.
IMPORTANT NOTE: Always check the specific instructions from the manufacturer! Some manufacturers might have different minimums set for certain shingle types, and the minimum may be over 2:12. It is also a good idea to always stay in accordance with your state’s local building code requirements as well.
Why Is there a Requirement?
The reason for the minimum slope requirement is because at slopes under 2:12, water will either stand on the roof or take longer to evaporate and drain. This causes lateral water movement around the roof’s surface, and gives you a very good chance of water seeping through the roof where the shingles overlap.
About Low Slope Roofs Below 4:12
Here’s the thing… A low-slope roof will start to lose its ability to shed water at slopes lower than a 4:12 pitch. So, even though the minimum roof pitch for shingles is a 2:12 pitch, you want to be really careful how you go about your job if your slope is betwer en a 2:12 and a 4:12 pitch. Roofs with a pitch lower than 4:12 require a heavier layer of underlayment. The underlayment is your your waterproofing layer, that provides numerous benefits such as cushion, an extra moisture barrier, and a second line of defense after the job is completed.
Check out this video on asphalt roofing for low slopes:
Best Practices for Low Slope Roofs
For low slope roofs between 2:12 to 4:12, using a double layer of underlayment. The best option available to us thanks to technological advancements over the past 20 years is Self-adhering modified bitumen systems. (SAMBs) SAMB’s offer the best protection for underlayment on low slope roofs. They comes in a range of colors, and they don’t have to be torched or mopped on like it was in the past.
Low Slope Roofs – Before You Begin
- For slopes between 2:12 and 4:12, the minimum of a 19-inch strip of 15 lb. asphalt-saturated felt should be used along the eaves of the roof. Above 4:12 (and you may already know this is you are a roofer) but the standard overlap os only 2 inches.
- If you are in a high-wind area, plastic windstrips (plastic caps) should be used instead of staples or nails to avoid having the wind tear up your material. Plastic caps help secure your material, and they also offer better leak protection through the nail holes than staples or nails can.
- Follow manufacturer instructions to lay shingles! Here is a useful resource on installing asphalt shingles from Inspectopedia if you need one.
ALSO KEEP IN MIND:
All of your roofing components need to come together to form a system that works together to:
- Be waterproof.
- Be fire proof and wind resistant
- Protect from UV rays
- Meet structural load requirements
- Be compatible with your insulation material
- Withstand temperature extremes in your area
Minimum Roof Pitch for Shingles – Final Thoughts
You also want your roof’s surface to be clean and dry before installation. In the end, hiring the help of a professional roofer is always best. After all, your home is one of the biggest assets that you have. You can call on Sellers Roofing Company any time, day or night to set up a free roof inspection and estimate. We have friendly operators on hand to take your call, and we would be happy to come out and give you our expert opinion at your convenience!
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