Sustainable Roofing Materials: Affordability vs Sustainability Study

We asked industry experts to weigh in on what constitutes a sustainable roofing material, and compare how different materials stack up against each other in terms of sustainability and affordability.

Adam Graham
Apr 27, 2022
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11 min read

Climate change is a bigger issue facing the world than ever before. As homeowners become more aware of their own carbon footprint, they start by looking at how they can live in a more environmentally friendly home. One area of the home where there are increasing sustainable options is the roof. Roofs are a big investment, and balancing the desire to be more sustainable while keeping to a budget is not always easy. 

We asked experts to weigh in on just how sustainable various materials are. We then took the average cost of each of these materials and compared them to see the affordability of each. The aim is to uncover whether sustainable materials are an affordable option for the average homeowner. This information is presented in a graphic so that you can see the average cost and sustainability of each material.

But first, we need to understand what we mean when we refer to a ‘sustainable roof’.

What Makes a Sustainable Roof?

The term sustainability is often interpreted differently, making it difficult to group materials for comparison. For example, there is confusion between the terms eco-friendly, sustainable, and energy-efficient. Before going deeper into each roof’s characteristics, we asked experts to explain what makes a roof sustainable. 

What the Experts Say

Dr. James L. Hoff, President of TEGNOS Research, Inc., explains that some companies may use the term eco-friendly as a marketing tool to help convince buyers to purchase their product: “Eco-Friendly is really more of a marketing term rather than a quantifiable functional concept (...). Sustainability is a much more quantifiable concept with recognized definitions and measures used throughout the world. In terms of a broad definition, The Brundtland Commission of the United Nations has provided the most recognized definition for sustainability as something that ‘meets the needs of the present without compromising the ability of future generations to meet their own needs.’

Eugene Colberg from Colberg Architecture goes more in-depth into the many factors that influence how sustainable a roof is by saying, “To maximize sustainability, we must keep in mind the full picture of the material.” He adds, “When it comes to sustainable roofs, materials are important, but it is necessary to think about and analyze the entire assembly in order to determine how ‘sustainable’ they are. Three key factors that dictate this are how much energy is involved in its manufacturing, what is the life cycle of the product, and how much carbon emissions are expended in delivering the product to the building site.”

In other words, for a roof to be considered sustainable, it needs to do its job as a roof for your home, without sacrificing any elements that make it function while also helping ensure that it does not have a negative impact on the environment for the future, during its manufacturing process, and distribution. This can mean roofing materials made from natural and renewable resources, materials that can be recycled or are made from recycled content, and roofs that help lower energy costs and energy expenditure.

Determining whether a roof is sustainable is not easy and will change depending on various factors, such as where you live. Colberg explains:

For example, if you live in Arizona, where a wood shingle roof has to be shipped from Georgia, that might not be as sustainable as a clay tile that is locally manufactured. While solar panels are an emerging frontier for energy, they are often shipped from China so we must keep in mind these invisible costs and hidden properties on a product or assembly. While metal takes a lot of energy to make, it lasts a long time. Green roofs take almost no energy to make, but require a lot of maintenance.

Sustainable Roofing vs Affordable Roofing

When people think about sustainable roofing, solar, cool, or green roofs often come to mind first. Hoff says, “...I think any roof to be considered truly sustainable first must be a cool roof, a green roof, or a solar roof. All other roofing options have significant drawbacks, especially in terms of negative impacts on global warming. Choosing among these options is mostly a question of functional requirements and cost.”

However, not every homeowner can afford a green or solar roof as sustainability and affordability do not always go hand in hand. That is why we asked experts to rate on a scale from 1 to 5 for how sustainable various roofing types and materials are and then added the average cost per square foot of each. We compared them in a chart to see how affordable and sustainable each of the various roofing options is.

Scatter graph showing affordabilty and sustainability of various roofing materials

As you see in the graphic above, sustainability and affordability vary tremendously. Some materials like asphalt shingles rank low in both cost and sustainability, materials like green roofs score high in both, and materials like wood and rubber roofing score at the midpoint. Below, we outlined the different options of how they rank in sustainability.

Sustainable Roofing Options and Their Cost

Cool Roofs

Cool roofs received the highest combined ranking for sustainability and can also be more affordable with an average cost of $12.50 a square foot. Many different roofs can be considered “cool.” To meet the definition, it must reflect the sun’s rays and absorb less UV heat than a standard roof. This means you can have cool metal roofs, tile roofs, and even white and reflective asphalt and architectural roofing shingles. Cool roofs are ideal in hot climates and places with a high heat index. Keeping the roof cool can prevent superheating of the attic, helping keep your energy costs lower. While this is not a good fit in all climates, it can be the best option for very hot ones. Colberg points out that in such climates, “Cool roofs are the least expensive and check the most boxes for homeowners.”

Green Roofs

A green or living roof comprises layers of soil, membranes, and living plant material. They come in a few different types, from extensive to intensive, and can also include some solar features. Green roofs received the second-highest score for sustainability, behind cool roofs, but they are also the most expensive at an average cost of $22.50 a square foot. Depending on the roof slope, climate, and building type, this roof can be very insulating and help with rainwater management. However, they can also be very heavy and may require you to reinforce your roof deck. Green roofs are not always recommended, as Colberg points out, “To have a green roof you need a flat roof, and most houses do not have one.” He adds, “Green roofs take almost no energy to make, but require a lot of maintenance.” 

Metal

Metal roofs score 4 out of 5 on the sustainability scale and cost an average of $10.50 a square foot. There are many different metal roofs on the market, and many of them can be very sustainable. Metal roofs can be given a reflective coating to make them a cool roof. They can also be insulated, helping lower energy costs. The material they are made from is also recyclable and may be made from recycled metals as well. According to Thomas Jepsen from Passion Plans, “In terms of roofs, going with a metal option, is really one of the most sustainable options out there. A lot of people think ‘metal, that’s not sustainable,’ however as it’s as recyclable as it is, it really does end up being among my top choices for green living. These also last an impressive amount of time for something that takes as much of a beating as roofs do!”

Solar

There are many options for solar roofing today. There are solar shingles made popular by Tesla, as well as integrated solar panels and interlocking metal solar panels. This gives solar roofs a much bigger range of options than before, making them more attractive to homeowners. They score 4 out of 5 and have an average cost of $18.50 a square foot. This can make them pricey, but they help pay for themselves by lowering your dependency on the electricity grid. As Zach Reece from Colony Roofers points out, “Tesla’s foray into solar roofs really increased the visibility and popularity of it.” And as more homeowners realize that these roofs exist with the different style and installation options available, they may begin to invest more. 

Rubber

Rubber roofing, specifically ethylene propylene diene monomer (EPDM), is a newer material that is beginning to catch on in style and sustainability. This material can be shaped into shingles or tiles that mimic the look of cedar or slate shingles. It is very durable, and the key with rubber is ensuring it is made from recycled material. As Jepsen points out, “Recycled rubber roofs are often made from old tires, and in areas with a lot of hail, they’re preferred over metal, as they won’t dent nearly as easily. The shock-absorbency of the material makes it a superior choice if your region has harsher weather than materials like clay or metal, which may crack.” Because not all rubber roofing is recycled, it scores 3.5 out of 5 but has a more attractive average price of $7.50 a square foot. 

Clay Tile

Clay tile roofs are not as common as some other materials, but they offer a good mix of sustainability and durability for homeowners in some regions. Clay tile roofs are popular in hot and tropical climates because they can withstand the heat and the storms of these areas. They can also be coated in reflective materials to act as a cool roof, and they can insulate the home, offering some energy benefits. However, clay tiles are expensive at $17.50 a square foot and score just over 2.8 out of 5 in sustainability. 

Wood Shakes and Shingles

Wood shakes and shingles are typically made from cedar, although they can also be produced from other species. These roofs are biodegradable, which can be attractive, and if the trees are harvested sustainably, they also offer a greener alternative than materials that need to be factory-produced. However, they are not as long-lasting as many options, and cedar often has to be shipped from the West Coast, decreasing its sustainability for East Coast installations. Jepsen also states, “While the wood is a replenishable material, there’s a lot of upkeep compared to other products, and I feel that warrants lowering its sustainability score. That is especially the case since you’ll end up having to replace the roof if you don’t take care of it.” It scores 3 out of 5 and costs $10 a square foot on average. 

Slate

Slate roofs are one of the longest-lasting roof options available. They can last up to 200 years when installed and maintained properly, and therefore, they are often considered a good choice for historic homes. They are one of the more costly options at an average of $20 a square foot. They score just under 2.7 out of 5 for sustainability. However, slate is a very durable material and will last for a long time. Given its uniqueness, we score it lower in sustainability. Unfortunately, for unique products, you are forced to replace the entire roof if there are leaks because you cannot match the existing material. Since it can be hard to fix issues, we are forced to give it a low sustainability score.

Architectural Shingles

Architectural shingles are a very attractive option for many homeowners. They are a built-up laminated version of traditional asphalt shingles. They last longer and can be made to resist things like hail, wind, and algae, making them lower in maintenance than asphalt shingles. However, despite having cool roof options available, they are not considered a very sustainable option, scoring 2 out of 5 with a cost of $10.50 a square foot on average. 

Asphalt Shingles

Asphalt shingles are very popular among homeowners for their affordability. They cost an average of $3.50 a square foot, but they only score 2 out of 5 on the sustainability scale. They can come in light colors to fit the profile of a cool roof, but they are most often used for their low cost. The material would need to change either in production or material to raise its sustainability, but doing so would also likely raise its overall cost. 

Choosing Among Sustainable Roofing Options

These are only a small selection of the roofing materials available. Each year, manufacturers offer new roofing material types and improve the ones they already make. In addition, costs can change over time. As demand rises for newer and more sustainable materials, costs may fall at the same rate. 

In addition, it can sometimes be difficult to establish the sustainability of a material. As manufacturing changes and practices develop, sustainability can change. For that reason, keep in mind that how a material is made and what practices the manufacturer uses may influence its overall score.

Contributors:

Methodology:
We contacted industry experts in order to get their insights on roofing materials and the sustainability of each. We asked them to rate roofing materials on a five point scale in terms of sustainability. The materials we chose for them to rate were based on well-known sustainable materials as well as some of the most popular roofing materials. We combined their answers and compared them to the average costs of roofing materials according to Fixr.com cost guides.

Author: 
Adam Graham is an industry analyst at Fixr.com. He analyzes and writes about the real estate and home construction industries, covering a range of associated topics. He has been featured in publications such as Better Homes and Gardens and The Boston Globe, and written for various outlets including the National Association of Realtors, and Insurance News Net Magazine. He contacted and interviewed industry experts to rate the sustainability of various roofing materials on a 1-5 scale, and then combined their answers.