Roof slope is an important aspect of roofing. Since the slope of a roof determines the angle of incline of the roof’s surface with the horizontal, it always makes homeowners question the importance of a roof’s slope during the installation process, as well as its necessity.
The correct measure of a roof slope also determines the longevity of the roof. In snowy regions, the steeper the roof slope is, the longer the roof is likely to last. Overall, a roof slope gives an aesthetically pleasing look to your home and reflects your living standards.
If you are a homeowner looking to replace or install your roof, or a contractor seeking to understand the nuances of roof installation, this article is for you.
What Exactly Is A Roof Slope?
In simple words, roof slope is the measure of incline to the angle it makes with the roof run.
To understand the roof slope precisely, we must know its measurement parameters.
Slope Measurement Parameters
To understand architectural measurement, we need to go back to math class for a second.
We know what a triangle looks like, and this basic understanding helps us understand the roof slope, rise, run, roof span, and pitch. So let’s get started.
A sloped roof looks like a triangle or, more accurately, a right triangle. A right triangle, as you know, is formed with a base, a hypotenuse (sloped roof surface), and a perpendicular line (a vertical distance) to the base.
The hypotenuse, or what is known on the roof as a sloped roof surface, makes an angle with the horizontal distance and is what gives a roof its sloped look.
The Roof Run
In roofing, the base (the horizontal distance) of the triangle is the run of the roof. The roof run extends from one wall of the home to the right below the center of the ridge.
The Roof Span
The roof span, different from the roof run, is the horizontal distance between the outer edges of the roof. It is a flat surface that shades the home interior. The roof run is shorter than the roof span.
The Roof Rise
The vertical distance between the middle of the roof deck and the roof ridge is the roof rise. It determines the steepness of the slope and the cost needed to install the roof.
The Slope
The slope of the roof is a measure of the roof’s steepness. The steeper the roof is, the steeper the slope becomes. Residents in the snowy regions prefer steeper slopes, while homeowners who receive little to no snow say that, flat or low-sloped roofs work well. The roof slope is measured as the change in the roof’s rise compared to the change in the horizontal run.
Roof Slope And Pitch Are Different
Homeowners often use roof slope and pitch interchangeably, but both terms are different.
Roof slope is the angle of inclination of the roof’s slope with the horizontal run. It is expressed as the ratio of the rise (vertical distance) to the run (horizontal distance) of the roof. Roof pitch, on the other hand, refers to the steepness of the roof and it is often expressed differently.
Roof slope and pitch are essential aspects of a roof. They together determine the appearance of your roof and the cost of installation.
Two Types of Slopes
Based on their roof slopes, roofs are of two types: steep-sloped and low-sloped roofs. Now that we know how to measure the slope, let us dive into more detail about the two different types.
Steep Slope Roof
A slope is a measure of how steep the roof is. Specifically, slopes define how much the roof rises vertically per 12 feet of horizontal length. If the vertical rise of the roof is 1 inch per 12 feet of its run (horizontal distance), we numerically write the slopes as 1:12.
Furthermore, if the vertical rise of the roof is 3 inches per 12 feet of horizontal length, then we write the slope of the roof to be 3:12. It’s important to note that, if the slope of the roof is greater than 4:12, we consider the roof to be a steep slope roof.
One advantage of constructing a steep slope roof on your residence is that it helps rain and snow quickly slide off your roof, and prevents the formation of ice dams.
Low-Slope Roof
A low-slope roof, also known as a flat roof, is a type of roof with a gentle slope. In contrast to traditional steep roofs, low-slope roofs tend to require more maintenance and have a lower construction cost. Additionally, they are the best choice for people living outside snowy regions.
Numerically, the slope of the low roof slopes is measured to be 3:12. A roof having a slope equal to or less than 3:12 falls into the category of a low-slope roof.
Although low-sloped roofs are also known as flat roofs, all flat roofs are not entirely flat. Instead, these roofs do have a slope to a certain degree that is feasible for water drainage, however, a common downside of these roofs is that they tend to collect ponded water. Low-slope roofs located in snowy regions of the country may also require more maintenance since the weight of falling snow can cause some low-slope roofs to collapse.
How Roof Slope Affects Roof Installation
Roofing service companies install roofs for residential, commercial, industrial properties, and more. Many of these services involve the installation of roofs and waterproofing them, but a proper roof installation will depend on several factors, including roof slope.
The roof’s slope is measured in inches or degrees between horizontal and vertical surfaces. For example, a roof that has a slope of 3:12 is a low slope roof, and roofs above 4:12 are steep sloped roofs.
At the same time, we can’t deny the fact that roof slopes affect roof installation. Do you want to know how and why? Keep reading till the end.
Affects The Installation Cost
The primary factor that slope affects during the installation process is the cost. Not only does it require more materials, but it demands more labor too. Though steeper roofs affect the installation cost, they are the best option you can have if you live in a snowy area. The requirement for different materials and the respective contractor may increase the charge of your roofing bill compared to that of a low-sloped roof.
Requires Additional Materials
Earth’s gravity plays a significant role in keeping your steep slopes sturdy and balanced. The higher the snowfall from above, the more likely the weight of the snow may weaken the structure and materials your roof slope was made of.
Since steeply sloped roofs are made using strong materials, these roofs tend to cost more. In addition, the stronger material is more likely to keep the water from seeping into your roof.
Pros And Cons Of Roof Slopes
Steep sloped roofs can be challenging to work on, but there are some pros. For example, the higher the slope of a roof, the faster it dries after rain or snowfall, but there are more pros to them that you need to know.
Pros
These are some of the advantages of having a sloped roof that you need to know.
Water Shed Off
The main factor that motivates homeowners to construct a roof with a steep slope is water drainage. People living in areas with frequent rain struggle more with their roof if it is flat. This is due to standing, or ponded water, that has collected after rain. This is a primary concern among homeowners, but luckily sloped roofs can reduce the chance of standing water from happening.
Withstand Snow
Steep-sloped roofs are preferred for snowy climates since they are built to withstand large amounts of snow. They can help reduce the risk of ice dams and also reduce the need for snow barriers.
Aesthetic Appeal
Steep-sloped roofs can offer a great deal of aesthetic appeal to a building. Roof slopes can vary greatly in size and degree, with many factors influencing their design. The size of your home and its shape also plays an important role in this aesthetic appeal. Steep slopes also free up more space in your attic and allow you to occupy that freed space accordingly.
Cons
Although there are more advantages to having a sloped roof, they also come with some cons.
Increase In Installation Cost
As discussed above, the cost of installation is quite high for steep sloped roofs compared to flat roofs. Though sloped roofs are aesthetically appealing, they are more costly and require more labor and time. Since more material is also needed to cover the lengths of a sloping roof, this increases the installation cost as well.
Looking To Install A Roof? We Can Help!
The slope of your desired roof will directly affect the roof installation process. If a roof is installed incorrectly, it can lead to water damage and require frequent repairs. If you have questions about the desired slope of your roof, call our team at Champion Exteriors.
Our team of professional roofers has been helping homeowners in New Jersey with our roofing expertise for years. We provide residential roofing services such as roof inspection, roof repair, roof replacement, and help with metal roofing systems. In case you’re not satisfied with your current roof for any reason, contact us today at (609) 845-3576 for a free roof inspection, and see how we can help!