When it comes to sustainable roofing, not all “eco roofs” are created equal. You’ve probably heard the terms green roof, blue roof, and brown roof — but what do they actually mean? And which one makes the most sense if you’re considering solar panels?
Let’s break it down: What is the difference between a green roof a blue roof and a brown roof?
What is a Green roof?
A green roof (also called a living roof or vegetated roof) is covered with plants — from sedum and grasses to wildflowers and shrubs. These roofs sit on top of a waterproofing layer and often include drainage and root barriers.
There are two main types:
- Extensive green roofs: lightweight, low-maintenance, shallow substrate, ideal for sedum
- Intensive green roofs: deeper substrate, more varied planting, higher load and maintenance needs
Benefits include:
- Rainwater absorption and reduced runoff
- Improved thermal performance and roof lifespan
- Urban biodiversity and pollinator support
- Cooling and air quality improvement
Green roofs pair very effectively with solar, particularly when using systems designed to preserve the vegetation (more on that below).
What is a Blue roof?
A blue roof is designed specifically to manage stormwater. It doesn’t rely on vegetation, but instead temporarily stores rainwater on the roof surface and releases it slowly via a controlled drainage system.
Blue roofs are often used in urban areas where space for ground-level attenuation is limited. They help prevent sewer overflows and reduce flood risk during heavy rainfall events.
Sometimes, blue and green roof technologies are combined — creating a blue-green roof system that offers both stormwater management and ecological benefits.
Learn more about Blue Roofs here.
What is a Brown roof?
A brown roof is also known as a biodiverse roof or wildlife roof. Unlike a typical green roof that is planted intentionally, a brown roof is designed to be left undisturbed and colonised naturally over time by local species.
It often uses recycled or bare growing mediums (like crushed concrete or sand) to encourage the establishment of native wildflowers, insects, mosses, and birds. Brown roofs are particularly popular in biodiversity net gain schemes and ecological planning strategies.
The short answer: Green roofs are the best match for solar, especially when paired with the right PV system and mounting approach.
At PV Plus, we specialise in designing and installing commercial solar PV systems for green roofs — and we tailor the solution based on your specific building, budget, and roof condition.
- For new-builds or full roof replacements, we often work with Bauder’s Biosolar system, which integrates solar modules directly into the green roof build-up. It’s fully compatible with Bauder waterproofing and drainage systems, and ideal when the roof is being constructed or upgraded from scratch.
- For retrofits on existing green roofs, we are one of the only UK-approved installers of OverEasy Solar — a lightweight, plug-and-play PV system that sits on top of the vegetation with no need for ballast or fixings. It’s fast to install and doesn’t disturb the waterproofing or biodiversity.
We don’t push one product — we help you choose the right solution based on your roof’s structure, condition, and sustainability goals.
Learn more about green roofs with solar panels
