What is a Green Roof?

Green roof

In a hole in the ground, there lived a hobbit.

That’s the opening line to JRR Tolkien’s book The Hobbit, which introduces us to hobbits, the Shire, and the whole setting of the Lord of the Rings.

It’s a place that’s designed to be as cosy as possible; a delightful landscape which complements the surroundings; a wonderful, warm homestead.

Why is it relevant to us at PFR? Because for many people, reading about (or watching) hobbits is the first place we come across the idea of a green roof – a roof that’s covered in grass and plants and gives your building a truly eco-friendly natural touch.

Who doesn’t want to live in a hobbit hole?

Read on to find out everything about green roofs!

What is a Green Roof?

Also known as ‘sedum roofs’ or ‘living roofs’, green roofs are growing in popularity thanks to their environmental and aesthetic benefits. They are flat roofs that are specifically designed to be covered with plants and vegetation that can range from low-growing mosses and sedum plants to small shrubs and wildflowers – it all depends on the roof structure and weight capacity.

Green roofs are a lot more than just slapping some earth and grass on top of a standard flat roof. They are a dedicated type of roof, designed specifically with a drainage membrane and root barrier to protect the building below from the nature housed on top of it.

There are three main types of green roofs:

  • Extensive green roofs – A shallow roof environment, good for sedum plants, grass and wildflowers (and bees!). These roofs are beautiful and low maintenance, but not for walking on, other than for maintenance purposes.
  • Intensive green roofs are deeper roofs with a more substantial underlying structure that can be walked on. They are complete roof gardens that can even include water features.
  • Biodiverse green roofs – Developed more for their environmental and wildlife benefits than as gardens, biodiverse roofs are designed to fit in with the local ecosystem.

What Are The Benefits of a Green Roof?

There are a whole host of benefits of a green roof – both for the environment and your property, including:

  • Improved insulation
  • Soundproofing
  • Additional outside space
  • Increased biodiversity
  • Water management
  • Improved air quality
  • Extended roof lifespan
  • Aesthetics
  • Property value

It’s easy to see why Bilbo Baggins was such a fan!

Are There Any Drawbacks to a Green Roof?

Of course, there are some downsides, or surely everyone would have one. The following all need to be considered:

  • Cost – There’s no denying that creating a green roof is more expensive than some other flat roof options.
  • Weight – One of the most important considerations is to ensure the underlying structure can hold up the green roof, as it can be quite heavy.
  • Maintenance – Like a garden, you need to weed your roof as well as water it in dry spells. Sedum green roofs are pretty self-sufficient, but even then some degree of gardening enthusiasm is needed.

Is a Green Roof Right for You?

Do you have a hobbit-like temperament? Whether a green roof is a good idea and suitable for your home will depend on the following:


A green roof definitely has a specific look – is this something you want for your property? The chances are that if you are considering a green roof, you have already thought about this, but do consider how it will fit in with the surroundings.


A survey will be needed to ascertain whether your building can hold up the additional weight of a green roof system. This doesn’t have to mean a flat ‘no’, but you may need to cut back from an intensive or bio-diverse roof and consider an extensive green roof if the physical support just isn’t capable of holding up the heavier roof environment.


If you are looking for additional space, then a roof garden might be the perfect option for you, but remember that an extensive green roof won’t be rated to support your weight for more than maintenance needs.


Green roofs can be expensive to install. It’s important that you consider both the immediate budget requirements and long-term maintenance and upkeep.


Maintenance does mean some regular gardening and care of your green roof. Like a garden, if you leave the roof untended for an extended period of time, it can grow out of control. Unlike a garden, however, an untended green roof can have more serious consequences for your property. Though it won’t take too many hours, having a green roof is a long-term commitment.

How Much Does a Green Roof Cost?

It’s impossible to provide a true estimate of the cost without a full survey of your property, but the following are the factors that will be considered:

  • Size
  • Complexity
  • Difficulty of access
  • Type of green roof
  • Materials
  • Plant choices

Use our online calculator to generate a ballpark estimate, which will give you a good indication of what to expect.

Installing a Green Roof with PFR

We’re seeing a steady uptrend in the number of green roofs being installed in towns and cities as green space becomes limited. This is not surprising, as the ecological and wellbeing benefits of having a green roof combine with modern practicality to offer an excellent roofing solution.

If the idea of being a little bit hobbit-like appeals, then why not contact us at PFR for some expert advice?

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