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How Roof Shape Affects Replacement Cost

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Ann Davis is an avid HubSpot-certified Content Marketer in the Technology, Health and Wellness, and Home and Lifestyle niches.

The cost of replacing your roof depends on various factors, among them being its shape. When you invest in a new roof, it protects your home from weather elements. It also potentially saves you a good amount of money on repairs and energy bills. Besides, roof replacement also enhances your home's curb appeal and resale value.

How does the shape of the roof account for the replacement costs? Keep reading to find out.

Roof Pitch or Slope: What is it, and How is it Determined?

One of the factors that contribute to the shape of the roof is the pitch or slope. The rise refers to how steep the roof is. Roofers usually calculate the roof slope by determining how much height the roof gains in a set horizontal measurement. The result is usually represented in a fraction like 3/12 or 6/12. The numerator refers to the vertical rise of the roof in inches. The denominator is the span of the roof or the horizontal distance it requires to rise.

The denominator is usually 12 because it represents one foot. This means that a roof slope of 4/12 would rise 4 inches for every horizontal foot. The horizontal distance is measured from the gutters to the peak of the roof. An unusually steep slope will cost more to replace than a relatively flatter one.

Why Does Roof Slope Differ?

Nearly every home has a different roof slope. For some homeowners, the shape is just an architectural design. However, the slope of a roof does play a specific function. The steeper the slope of the roof, the easier it is for snow and rainwater to slide off. This is why most homes in the Midwest and Northeast have steeper roofs. Roofs in Southwest are flatter, as they don't experience a lot of precipitation.

The two most common roof slopes are the high roof slope and the low roof slope. High roof slopes are common in classic home styles in New England. Excellent examples are the Victorians and Colonials. The roofs are steep and give them a dramatic look. The design makes it easy to get rid of all the snow in winter.

Low roof slopes became popular in the 50s and 60s because they are easier to put up. Most craftsman homes and traditional ranches have lower roof slopes.

Why do Steep Roofs Cost More to Replace?

Anything more than 8/12 is considered a steep roof and will cost more to replace. The reasons for the extra cost include:

  • Difficulty in walking on the roof- steep roofs are not easy to walk on, which means that the roofer is at risk of falling off.
  • They require additional safety equipment because of the risk they present to the roofer. The contractor and his team may need rigging and scaffolding for their safety when working on the roof. The equipment costs a lot to purchase or rent and takes time to set up.
  • Complex installation techniques- steeper roofs require a high level of proficiency and expertise. They need extra work to ensure they stay in place, and roofers have to use more nails per shingle. Somewhat flatter roofs are easy to install, with each shingle requiring a minimal amount of nails.
  • Competition- not all roof contractors have the right tools and an experienced team to work on steep roofs. That means less competition for roofers who can handle the work. This leaves them to set their prices a bit more freely. However, don’t just take the lowest bid; do your homework to ensure the roofer you choose can do the job.

Peaks and Valleys in the Roof

Peaks and valleys in the roof determine its shape and hence influence the costs or replacement. Anything that requires two planes to join, like a chimney and skylight, will require more time, materials, and attention. Peaks and valleys call for undivided attention, without which they are prone to leaks if not done correctly.

Type of Roof

The type of roof also determines its shape and affects the replacement cost. The cheapest roof to replace is a skillion roof because it has a straightforward process. Some common roof types are:

  • A hip roof that looks like it has ‘hips’ at the ends of gables
  • A gambrel roof, which is divided into four parts. It also has a large overhang
  • A mansard roof that closely resembles a barn roof
  • Dormer roof with extra roofing for windows
  • A gable roof that assumes an inverted ‘V” shape

Other roof types can have more complex shapes, which will increase the cost of replacement.

Final Thoughts

The shape of your roof will determine how much you pay for its replacement. When asking for quotes from roofers, ask for itemized estimates so that you know exactly what you’re paying for. A professional roof contractor will only give you an estimate after inspecting the roof for its shape, condition, size, and other vital factors.

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