How to Make a Living Roof
Although the thought of creating a living roof could be daunting, especially for those who are scared of heights - the process is still straightforward however extra caution should be taken when working at a height - so ensure your ladders are fully secure before you climb them.
In this blog we will discuss the benefits of a living roof as well as a step by step guide on how to create your own at home or on a garden shed. Please keep in mind that the process of laying turf on a roof is different than laying it on the ground level. If you want to find out how to lay turf on the ground, check out our turf laying guide here:
Living roof benefits:
- Increased protection & longevity of your roof – the turf on top of your roof will protect your roof from the elements as well as wear & tear.
- Better drainage: Your gutters wont be required as much – as the living roof will retain lots of water and moisture from rainfall
- Insulation – increased insulation keeps the interior warmer and can reduce energy usage in the colder months as the building retains more heat. The interior will also be noticeably quieter during rainfall as the water is not bouncing directly off your roof anymore.
- Great for the environment – adding wildflowers to your living roof is great for local wildlife such as bees and other pollinators.
What you will need:
- Tape Measure
- Staple Gun
- Garden Hose/Watering can
- Pond liner/waterproof plastic sheet
- Root membrane
- Your choice of turf or wildflowers
- A roof
Ensure your roof is structurally sound:
The first step to creating a living roof is ensuring that the roof you wish to install your turf is structurally sound enough to take the weight. Turf is surprisingly heavy, particularly when it is very wet – as it will retain lots of the moisture from rainfall. The last thing that you want is to finish creating your living roof for it to collapse! As a guide, each meter square of turf can easily weigh 25kg, the topsoil and timber your use will obviously both add additional weight.
Constructing the frame:
The first step is creating a timber frame around your roof which we will use to staple a waterproof sheet plastic to ensure that water does not leak into the building interior. This frame will help contain the entire living roof and ensure that any soil or turf don’t simply fall off.
We will also need to install a waterproof pond liner & a root membrane to stop the roots penetrating too deeply where they may penetrate the pond liner. This is sometimes known as a moisture blanket and is available from all good garden centres, as it is most commonly used in garden borders or underneath garden decks to prevent weeds growing inside them.
Here is a diagram of how you should arrange the different layers:
Begin by measuring up the outside of your roof, measure twice and cut the timber to size. If you are building a living roof on a wooden shed, you can fix the frame to the roof with some decking screws.
Unroll your pond liner and cut to size, you will need to cut a slightly bigger area so if can be secured to the timber frame properly. Take care with this step and ensure that you don’t accidently rip or tear any holes into the pond liner – otherwise water will soak through onto the roof. With a staple gun, secure the pond liner to the inside of the wooden frame. Repeat the same process with the root membrane and secure it to the frame without stretching or tearing any holes in it.
Now it is time to add soil to the finished frame. Be very careful when lifting heavy weights on ladders, if you have individual packs of topsoil e.g. 25L bag, take up one at a time and open it on the roof. If you have a loose load of topsoil – grab a bucket and take up one load at a time to prevent any accidents. Rake the soil evenly across the frame ensuring all of the membrane is covered. You will want at least 2-3 centimetres of depth.
Laying the turf:
With the turf ready to be laid on the roof, unroll them one at a time and lay next to each other in a pattern that may resemble a brick wall. Be careful not to stretch or tear any pieces – however if you do, simply patch it up with another piece of turf.
Now the living roof is complete, give it a good watering to help it adapt to its new environment! It won't take long for the turf to knit into its new environment and it will be heavy enough to sit on top of the roof until it does.