Ever looked up and seen grass or plants growing on top of a building? That’s a green roof, and it’s more than just a pretty sight. But how does it compare to a traditional flat roof?
At Hoel Roofing, we’ve worked on roofing systems for over eight years and have helped many homeowners and business owners determine which option is the better choice for their property, budget, and long-term maintenance needs. Now, we’re going to help you get some clarity, too.
In this article, we’ll compare green roofs and flat roofs side by side: how they work, what they cost, pros and cons, and which might be the best fit for your home or business.
A green roof is a rooftop covered with plants instead of traditional materials like shingles or tiles. It’s built in layers, including vegetation, soil-like growing medium, drainage systems, and waterproofing.
At its simplest, a green roof works like a sponge and a blanket combined. When it rains, the soil and plants absorb water instead of letting it run straight into drains. This reduces flooding and eases the strain on stormwater systems. According to the EPA, green roofs can hold 40–80% of rainfall, depending on their design.
Green roofs also act as insulation. In summer, they help keep buildings cooler by blocking heat. In winter, they add a layer of warmth. And because plants naturally filter pollutants, green roofs can help improve air quality around your home or business.
A proper green roof isn’t just dirt piled on your shingles. It’s built in several layers, usually including:
Almost any building can have a green roof if:
If you’ve ever stood on a rooftop that felt more like a patio than a steep slope, you were probably on a flat roof. A flat roof isn’t perfectly flat; it usually has a very slight slope, allowing water to drain off. But compared to a typical shingle roof, it looks almost level.
So technically, a green roof sits on top of a flat roof. You can have a flat roof without plants, but you can’t really have a green roof without a flat or gently sloped surface underneath it.
| Feature | Flat Roof | Green Roof |
| Primary Purpose | Keep water out of the building | Manage stormwater, provide insulation, and create green space |
| Surface Material | Rubber, asphalt, plastic, or coatings | Plants, soil, and drainage layers above waterproofing |
| Weight | Light to moderate | Heavier due to soil and plants |
| Appearance | Plain, often white, gray, or black | Green, natural, and vibrant |
| Cost | Generally lower | Higher initial cost due to extra layers and plants |
| Maintenance | Inspections, cleaning drains | Needs occasional weeding, plant care |
Installing a green roof in the U.S. typically ranges from:
For a 1,500 sq. ft. roof, that’s $15,000 to $60,000+, depending on the system.
Flat roof installation typically costs $10–$15 per sq. ft..
Do green roofs attract insects?
Not significantly. Green roofs attract beneficial insects like bees and butterflies, but rarely cause pest problems if properly designed.
Are flat roofs suitable for snowy or rainy climates?
Yes, but they must be designed appropriately for drainage and snow load.
How much weight does a green roof add?
Can you walk on either roof type?
Are green roofs fire-resistant?
Yes, when properly designed and maintained. Certain plants can reduce fire risk, but dry vegetation should be managed carefully.
We recommend to our clients in East Central Indiana to choose flat roofs over green roofs.
Traditional asphalt shingle roofs and metal roofing dominate Indiana’s residential and small commercial sectors, and it is for good reason. Indiana’s humid summers, cold winters, and frequent freeze–thaw cycles require extra insulation, waterproofing, and plant care for a green roof.
The Indiana weather conditions don’t rule out green roofs, but they do make them more expensive to install and maintain compared to regions with milder and more consistent weather. Flat roofs, on the other hand, are much easier to keep over a green roof.
Choose a Green Roof if you want sustainability, better insulation, a beautiful natural space, can afford the higher upfront costs and ongoing maintenance, and live in a place with mild weather conditions.
Choose a Flat Roof if you are working with a tight budget, prefer a modern look, and need easy rooftop access for HVAC, solar, or maintenance.
The best way to decide? Talk to a roofing expert who’s installed both systems and can help you weigh real-world pros and cons for your specific property or help you determine if you’re better off getting asphalt shingles or metal roofing.
Not sure which one fits your property best? Contact Hoel Roofing today for a free consultation and personalized quote. We’ll help you make a choice that protects your investment for years to come.
Toyosi Ogunsola is the Content Manager at Hoel Roofing & Remodeling in Rushville, IN, where she oversees the creation of educational, trustworthy content about roofing, remodeling, and home improvement. With a master’s degree in Emerging Media Design and Development and a background spanning content strategy, UX research, and digital marketing, Toyosi combines data-driven insights with clear, engaging writing to help homeowners make informed decisions. Passionate about translating complex roofing topics into helpful resources, she works closely with Hoel’s team of roofing experts to ensure every piece of content is accurate, practical, and user-focused.
