Roofer holding a tape measure and spirit level in his hands over newly installed tiles on a new build wooden house

Although low pitch roofing’s usually found on commercial buildings, some modern-style homes also feature this type of roof. 

Low pitch roofs are often called low slope or flat roofs, but no roof is ever truly flat. That would lead to water pooling on its surface, damage to the surface, and leaks. According to OSHA, a low pitch roof’s defined as having a slope of less than 4:12

What does this mean, and more importantly, does your roof fall into this category? If so, these are the facts you need to know when considering low pitch roof materials for your home or business.

How to Calculate the Slope of Your Roof

The ratio of a roof pitch describes its slope in two parts i.e. the vertical height of the roof compared to the horizontal length of the roof. For consistency, the second number (the denominator) is always shown as 12.

So, the pitch ratio always describes how many inches your roof rises every 12 inches. So, for a roof pitch of 4:12, your roof goes up by four inches or every 12 inches of length. 

According to this website, the easiest way to measure the pitch of your roof is from the inside. Hold a level against the top of one of your rafters and mark out 12 inches from where the roof joins your building.

Then, using a tape measure, record the distance from the twelve-inch mark straight up to the underside of the roof. This figure is the pitch of your roof. If this number’s above four, you can opt for one of the conventional roofing types like asphalt tiles.

If it’s less than four, you’ve got other options to consider.  

There are a few major considerations when choosing the best roofing material. These are:

  • Your budget
  • The durability of the material
  • Weather conditions in your area
  • Your color and style preferences

Bearing these factors in mind, you’ll find a range of roofing materials to choose from. 

Low Pitch Roof Shingles

You can install asphalt shingles on low-slope roofs with a minimum gradient of 2:12, such as a low pitch gable roof. Provided your contractors seal the shingles against wind lift and follow the necessary procedures, they work well for these types of roofs.

You might need to check your local building codes before you opt for this type of roof.

Metal Roofing For Your Low Pitch Roof

Metal roofs include several attractive low pitch options. You can choose from steel, aluminum, stainless steel, and copper roof sheets. 

Standing seam metal roofs suit roofs with pitches as low as 2.5:12 and are a supremely durable type of roofing. Metal roofs resist fire and extreme weather, but some types of metal can corrode over time unless treated.

Unfortunately, metal roofs are an expensive option to install and need ongoing maintenance. 

Built-Up Roofing

This basic type of tar and gravel roof’s a popular option since it’s supremely durable and can last up to 20 years. BUR consists of layers of hot bitumen and fiberglass asphalt sheets, with a layer of gravel stuck to the top layer of bitumen. 

Installing these roofs take time, so it’s an expensive choice when it comes to labor costs.

Modified Bitumen Roofing Systems

These roofs have five layers and consist mainly of asphalt mixed with a chemical polymer to add flexibility to the roofing system.

The layers consist of insulation, modified base sheets, co-polymer sheet membranes, waterproof adhesive, and bonding agent, surfacing for UV and weather resistance.

Roofing contractors install the sheets and then melt the seams together to form a secure bond that’s impervious to fire, hail, and wind. 

Single-Ply Low Slope Roof Systems

Contractors can install these types of roofing systems quickly and easily. They’re a flexible, hardy choice and consist of a single layer of roofing material applied over a concrete roof deck. 

There are three main types of single-ply roofing systems:

Polyvinyl Chloride

PVC, or Polyvinyl Chloride, is a tough, durable material commonly used for commercial structures. It offers energy-efficient benefits thanks to its reflective qualities and is a lightweight type of roofing. 

It’s an expensive roofing choice but has several benefits.

These roofing systems can resist, UV light, wind, fire, punctures, and many chemicals. They’re a good choice for buildings with ventilation systems that may emit oil and fat fumes. 

Thermoplastic Polyolefin 

TPO roofing is 100% recyclable and similar to PVC roofing when it comes to durability. They’re installed on a layer of expanded polystyrene, extruded polystyrene, or polyisocyanurate insulation. 

These roofing systems come in 10,12, or 20-foot widths and have a single layer of synthetic material with reinforcing scrim. Once they’ve rolled the sheets in place, your contractor welds the seams together using a hot air gun.

Ethylene Propylene Diene Monomer 

EPDM’s one of the best-established types of single-ply roofing with a 60-year history and good track record of durability. It’s made of rubber, so you can easily shape it to any type of roof.

EPDM’s black color works well in cooler areas and you can easily convert it into a cool roof to increase your building’s energy efficiency.

Liquid-Applied Roofing

Liquid-applied roofing’s made from polyester and resin and it’s easy to spread over your roof in its liquid form. It flows into every nook and cranny of unusually shaped roofs creating a watertight seal.

The roof’s applied on-site in two layers using a roller or sprayer. This time-consuming process can translate into expensive installation costs. On the plus side, you can easily repair this type of roofing by adding extra coats if necessary.

Make Great Choices for Your Home and Business

A low pitch roof offers many benefits over steep slope roofing. They’re usually lighter, more durable, and easier to install. Since you can walk on these roofs safely, it’s easy to maintain them too. 

Would you like to find out more about how to make informed decisions about your home and business? Explore our website for all the best tips.