The Influence of Roof Pitch on the Roofing Materials
Did you know that the pitch of your roof plays a crucial role in the choice of roofing materials?
Indeed, it’s important to note that certain types of roofing are not adapted to all types of sloped roofs; some materials are more effective on roofs with a low pitch, while others require a roof with a higher pitch to ensure optimal waterproofing and prevent risks of water infiltration.
By understanding the influence that roof pitch can have on the choice of materials, you’ll be able to make an informed decision as to the type of roofing you need to ensure your roof is efficient and durable.
But First, What Qualifies as a Sloped Roof?
Roof pitch is measured by the ratio of the roof’s height to its length, and it’s often indicated as a ratio or percentage. Accordingly, the pitch of a standard roof generally has a ratio of 4/12 or 33%, which means that for 12 horizontal units, the roof has 4 vertical units.
In general, a roof is considered a sloped roof when its pitch is equal or higher than 2/12 or about 16%.
The Influence of Roof Pitch on Roof Shingles
Roof shingles are particularly popular, and not without reason. In addition to offering great value for money, they can be installed on different types of roofs.
3-Tab Shingles
They’re a smart choice for roofs with a low pitch and they’re the most widespread and economical type of shingles.
Laminated Shingles
This type of shingles is adapted to standard roofs with a pitch higher than 4/12, and it has become increasingly popular in recent years, because of its distinctive design that gives more depth and dimension to your roof.
Architectural Shingles
This type of shingles, recommended for roofs that have an average to high pitch, is the most aesthetic shingle available and it offers various designs that look like wood or slate. However, it’s the most expensive type of shingles.
The Influence of Roof Pitch on TPO Roofs
Membranes made of thermoplastic polyolefin, better known as TPO, are designed for roofs with a low pitch or for flat roofs.
In contrast, TPO membranes are generally not recommended for sloped roofs, for various technical reasons :
Poor Adhesion
If they’re installed on roofs with a more significant pitch, TPO membranes can struggle to adhere properly to the structure, and they risk sliding.
Reduced Durability
If they’re installed on roofs with a more significant pitch, TPO membranes can be subject to more significant tension because of gravity, which can lead them to tear or warp over time, consequently reducing their lifespan and effectiveness.
Inadequate Drainage
TPO membranes are designed to optimize uniform drainage on flat surfaces. If they’re installed on roofs with a more significant pitch, there may be additional challenges to ensure the water drains properly without creating pockets or accumulations of water.
Consequently, TPO is better adapted for flat roofs or roofs with a low pitch, considering their design and installation process is optimized for maximum performance on this type of roof.
The Influence of Roof Pitch on Elastomeric Membrane Roofs
The elastomeric membrane is an alternative to tar and gravel roofs and it’s a waterproof roofing material that’s used mainly for flat roofs or roofs with a low pitch. For the same reasons as for TPO roofs, elastomeric membrane is generally not recommended for sloped roofs. It would have poor adherence, which might cause the material to slide and compromise the durability and waterproofing of the roof.
Consequently, to optimize the performance of elastomeric membrane roofs, it’s best to install this type of membrane on a flat roof or a roof with a low pitch.
In Conclusion, What Type of Roofing is Recommended for Which Type of Roof Pitch?
To ensure optimal performance and long-term durability, the choice of roofing materials must be adapted to the roof pitch. Here’s a summary of the types of roofing recommended according to the roof pitch :
Flat Roof
- TPO
- Elastomeric membrane
Roof with a Low Pitch
- TPO
- Elastomeric membrane
- 3-tab shingles
Roof with an Average Pitch
- Laminated shingles
- Architectural shingles
Roof with a High Pitch
- Architectural shingles
You need to replace your roof and you don’t know where to begin?
Contact our specialists at Couvreur Couv-Toit now. They’ll answer all your questions and will help you choose the best materials depending on the pitch of your roof!