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A Quick Guide To Creating a Green Roof For Your Garden Building

When it comes to choosing a roof for your home or garden buildings, why stick to the norm? By opting to make your roof a greener one you will be creating a stunning focal point as well as helping the environment. A green roof is a brilliant modern-day choice and here is our quick guide to creating one.

How Is a Green Roof More Environmentally Friendly?

A green roof can do all of the following:

  • Absorb heat from the sun
  • Absorb CO2
  • Absorb up to 70% of the rainfall that falls on them
  • Help to provide an insulating layer for your building
  • They replace some of the lost greenery that buildings/houses take away

The Three Types of Green Roofs


This green roof system consists of a thick layer of soil (50-200mm+) in which a variety of grasses, herbs, flowers and shrubs can grow. This type of roof will need to be accessible for maintenance but you must note that they can place significant weight on your building so you will need to ensure that there is substantial roof support. This system provides a wonderful habitat for wildlife as well as good water absorption.


This green roof is generally made up of a shallow layer (20-100mm) of soil and planted up with low-growing, stress-tolerant grasses, mosses and so on. This system requires little maintenance and should just tick over well all by itself.


A semi-extensive system sits in the middle of the above two. They have a slightly greater depth than extensive systems (100-200mm) but are not as heavy or require as much maintenance as the intensive.

How Do You Install a Green Roof?

In order for a green roof to grow and thrive you need to install a green roof system. The required layers are as follows:  

  • Waterproofing of the roof deck (your current roof may already have this)
  • Root barrier- to protect your roof
  • Drainage Membrane- to draw the water away and prevent excess water from causing structural problems
  • Filter layer- to prevent soil from filling drainage cavaties
  • Green Roof Substrate (you will need to look for specific blends for this project)
  • Vegetation
  • Good guttering to drain the water away

The ideal way of installing a green roof is to seek out a professional company that can carry it out for you. A green roof may look simple but it is vital that you receive the appropriate expertise depending on the roof type, building and area you have.

If you want to do it yourself, you must first do plenty of research, make sure that your roof is on no more than a 30° slant, that your building structure is sound and that your source your materials from a reputable company. You will need to follow the steps above in the order that they are listed. There are lots of great YouTube videos available for help like this one here.

Plant Options

The best planting options for a low-maintenance and simple green roof would be a variety of alpines, grasses, moss and bulbs. All of these do well in a variety of weather, can withstand a lot of rain and will return year after year.

Another option is to purchase pre-grown sedum mats that are ready to install. These provide instant greenery to any sized roof. You can find out more about planting in this article here.


The cost of installing a green roof can widely vary depending on which system you choose and whether you choose a company to carry out the work for you. With all materials, planting and installation you could be looking at costs between £600-£1400 (roof size will vary this). If you carried the work out yourself and sourced materials at low costs, this could significantly come down. The great thing is though, once this is installed, the roof should provide you with years and years of joy.

A Greener Future

Choosing a green roof is the ‘greener’ choice and will significantly help our environment now and long into the future.

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