Minimum Roof Pitch for Shingles – Expert Advice

Minimum Roof Pitch for Shingles Man Applying Tar to a Roof

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

  1. 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.
  2. 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.
  3. 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:

  1. Be waterproof.
  2. Be fire proof and wind resistant
  3. Protect from UV rays
  4. Meet structural load requirements
  5. Be compatible with your insulation material
  6. 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!

FAQs

What is the guide you need for your roof replacement?

The guide that is highly recommended for your roof replacement is The Complete Guide to Purchasing a Roof. This comprehensive guide provides you with all the necessary information and insights to ensure that you make informed buying decisions for your roof replacement project. It equips you with the knowledge and understanding needed to avoid going into the roof replacement process blindly. By accessing this valuable resource, you can gain access to a free buyer’s guide that will assist you in every step of the process. With The Complete Guide to Purchasing a Roof at your disposal, you can be confident in making the right choices for your roof replacement needs.

What is a standing seam metal roof?

A standing seam metal roof is a type of roofing system that consists of interlocking metal panels. These panels are secured together at the seams, either through mechanical means or by a locking mechanism. The design of this roof allows the panels to expand and contract smoothly during temperature changes, preventing damage caused by thermal expansion. One of the notable advantages of a standing seam metal roof is its suitability for flat roofs. It offers better aesthetics with a wide range of color options, giving homeowners the opportunity to choose a roof that complements their building’s overall design. Additionally, this type of roof is known for its exceptional durability and longevity compared to membrane roof systems.

When installed correctly and given adequate ventilation in the attic, a standing seam metal roof can last for at least 30 years. Under ideal conditions, it may even surpass 50 years of service life. However, it is important to note that this increased lifespan and aesthetic appeal come at a higher cost compared to the three types of roof membranes commonly used. Thus, budget considerations should be taken into account when deciding on the best roofing option for a specific building.

What is an EPDM membrane roof?

An EPDM membrane roof, also known as an ethylene propylene diene monomer roof, is a synthetic rubber material commonly used in commercial roofing and medical facilities. Although it is primarily utilized in commercial properties, EPDM can also be found in residential roofing applications. EPDM roofs are especially suited for flat roofs over non-living spaces such as garages or other similar areas. Due to its black color, it is not recommended to install EPDM over bedrooms or living spaces as it has the tendency to absorb heat.

However, this color also means that the membrane is less likely to get visibly dirty when viewed from a window, unlike white membranes. One of the notable advantages of EPDM is its exceptional durability. It can be compared to having a roof made of bulletproof rubber. With proper installation and maintenance, an EPDM roof with a thickness of 0.060 can last for an impressive 25 to 30 years. Overall, EPDM membrane roofs provide a long-lasting and reliable roofing solution, offering protection against harsh weather conditions and serving as an effective barrier against moisture.

What is a standing seam metal roof?

A TPO membrane roof is a type of roofing material that consists of a single-ply white membrane made from thermoplastic polyolefin. It is commonly used in both commercial and residential roofing applications. The main advantage of TPO roofing is its ability to reflect heat instead of absorbing it, which makes it particularly suitable for flat roofs or low-slope dormers, especially those situated above bedrooms. The white color of the TPO membrane helps in reflecting sunlight and heat, thus keeping the room below cooler. However, it’s worth considering that the visible portion of the TPO membrane may accumulate dirt over time. When installed correctly, a TPO membrane flat roof can be expected to last for approximately 25 years.

Why can’t you put shingles on a low slope or flat roof?

Shingles cannot be installed on a low slope or flat roof due to a few important reasons. Firstly, shingles are not designed to withstand the weight or constant presence of sitting water. If water accumulates on the surface of shingles, it can lead to various problems such as leaks, rot, and damage to the underlying structure.

To ensure proper installation and long-term performance, shingle manufacturers explicitly state in their installation instructions and building codes that asphalt shingles should not be installed on roofs with a pitch below a 2:12 ratio. Ignoring these instructions in an attempt to save money can result in shingles failing to fulfill their intended purpose effectively. Additionally, if the installation instructions are not followed, manufacturers may not honor their product warranty. This lack of warranty coverage can leave homeowners without recourse if issues arise with the shingles themselves.

While it may still be possible to address problems through a roofing contractor’s workmanship warranty, it is unlikely that a contractor who disregarded installation instructions would stand firmly behind their own work. In summary, it is crucial not to install asphalt shingles on a roof with a pitch below a 2:12 ratio. Doing so would not only compromise the performance of the shingles but also potentially forfeit any warranty protection, leaving homeowners vulnerable to potential issues without suitable remedies.

What is a TPO membrane roof?

A TPO membrane roof is a type of roofing material that consists of a single-ply white membrane made from thermoplastic polyolefin. It is commonly used in both commercial and residential roofing applications. The main advantage of TPO roofing is its ability to reflect heat instead of absorbing it, which makes it particularly suitable for flat roofs or low-slope dormers, especially those situated above bedrooms. The white color of the TPO membrane helps in reflecting sunlight and heat, thus keeping the room below cooler. However, it’s worth considering that the visible portion of the TPO membrane may accumulate dirt over time. When installed correctly, a TPO membrane flat roof can be expected to last for approximately 25 years.

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