Here’s What to Know When Deciding Between Bitumen and Asphalt for Your Roof

Katy Willis
Written by Katy Willis
Reviewed by Ami Feller
Updated April 6, 2022
A house with asphalt shingles on the roof
Photo: ma-k / E+ / Getty Images


  • Bitumen rolls are best for low slope and flat roofs.

  • Asphalt shingles have a longer lifespan and are more durable.

  • Which one you choose depends on your roof type and budget.

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A leaky roof is a headache for any homeowner and it needs to be addressed, pronto. If you find yourself needing to re-roof part of your home, then you'll need to choose the right roofing material. Bitumen rolls and asphalt shingles are among the most common types, so let's take a closer look at how they differ, and which one works best in different categories.

What Are Bitumen Rolls?

Bitumen roll, or rolled roofing, is an asphalt-based fiber-reinforced roof covering most commonly sold in 33-foot rolls that are 36 inches wide. It's fairly light weight and while comparatively durable for its type, bitumen roll is generally considered a temporary roof covering apart from when used for flat roofs and outbuildings like sheds, workshops, and garages.

Pro tip: You can also buy modified bitumen as a two-ply system; it has a base and a cap sheet. Without the base sheet most manufacturers warranty the cap sheet for 12 years and with the base sheet, it’s warrantied for 15.

What Are Asphalt Shingles?

Asphalt shingles are thicker, pre-cut rectangular roof coverings that overlap when installed. The material of choice for pitched roofs, asphalt shingles are made from asphalt and, usually, fiberglass mats. They have a comparatively long lifespan and are extremely durable, but not recommended for low-slope roofs. Most manufacturers rate their shingles from 20 to 50 years.

"In general, shingles are recommended for 3:12 pitch or more," says Ami Feller, Expert Review Board member and owner of Roofer Chicks in New Braunfels, Texas. "You can install them with a pitch of 2:12, but I recommend putting ice and water shield under the shingles at that low of a pitch. Modified bitumen is recommended for 5:12 to 3:12 pitch roofs. Mod bit is not made to handle ponding water, so you have to have a slope for it to work properly, even if it's just a small slope."

Which One Should I Use?

Which one you choose depends on a number of factors including what you're roofing, the type of roof you have, and your budget. Aside from budget, the biggest deciding factor is the type of roof you're covering. If you're covering a shed or garage roof, you may not be too bothered about appearance or longevity, in which case, bitumen roll is a smart, cost-effective choice. 

If you're covering a low-slope or flat roof, with a pitch under 2:12, you'll need to use bitumen rolls. While shingles are more durable, if you install these on a low slope or no-slope roof, because the water tends to pool or run off more slowly, there's a much greater chance that water will seep in through the joins between the shingles.

If budget is less of a concern and you're covering a pitched roof, asphalt shingles are your best option. This is because shingles are longer lasting, have a more traditional and pleasing appearance, and considerably more durable. 

Factors to Consider When Choosing Between Bitumen Rolls and Asphalt Shingles

A worker laying a bitumen roll on the roof
Photo: Imagesines / iStock / Getty Images Plus / Getty Images

When you need to install new roofing, there are a number of different elements to consider. Your local roofing contractor can advise you on the best option for your specific situation, but let's take a look at which roof covering wins in these key categories. Ask your roofing contractor what they recommend to find out if asphalt shingles are right for your roof.


Bitumen rolls typically cost less per square foot up front, but asphalt shingles last longer, so are a better investment long-term. Asphalt shingles cost $30 to $60 per 33 square feet plus $1.65 to $$2.65 per 33 square feet for felt paper underlayment. Bitumen rolls cost $10 to $20 per 33 feet, plus you'll need some mastic, which costs about $40 for a large bucket. For both types, you'll also need to account for hiring a local roofer, which costs an additional $40 to $80 per hour.


Shingles generally look more pleasing and have a more traditional appearance. However, bitumen rolls look perfectly acceptable on flat roofs and as roof coverings on sheds, outbuildings, and garages. 

Lifespan and Durability

Even high quality bitumen rolls cannot outlast asphalt shingles. Bitumen rolls last around 8 to 10 years while high-end asphalt shingles can last 30 to 50 years. Shingles are also more durable as they're thicker and stronger. Plus, if one or two shingles are damaged, you can simply replace those ones. With bitumen, if a tear or similar damage occurs, you can patch it—but it’s not always easy. In some cases, you may have to replace the whole strip. 

Ease of Installation

Bitumen is the easiest to install when compared to asphalt shingles. Bitumen is installed in rolls 3 feet wide and 33 feet long, with nails placed at regular intervals along the length. Each course or strip should overlap the previous one by about 4 inches and each strip should be sealed with roofing cement. When installing shingles, each has to be nailed into place individually, which is a more time-consuming process.

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