Green roofs for sheds: a how to guide

Shed green roofs are becoming more and more popular. They look great, transforming what can be a functional storage space into an attractive garden feature. Your shed structure also benefits along with local wildlife. So, it’s no surprise more people are looking to get one. 

A common barrier is misconceptions about the difficulty of installing one. With our sedum roof trays, setting up a green roof on your shed couldn’t be easier. Below, we take a look at the installation process.

What is a sedum shed roof?

A sedum shed roof is a layer of sedum plants that sit on top of a shed. Sedum are hardy, low-growing succulent plants that form a living ‘mat’. They require little maintenance, are drought-tolerant and are relatively lightweight, making them ideal for a shed green roof. 

You can establish a sedum roof in several different ways, but the easiest is using sedum trays. PermaSEAL Sedum Roof Trays are an innovative way to set up a sedum roof quickly and easily. Each tray contains everything needed to be completely self-sufficient, and the trays can be combined to fit a space of any size.

Can I put a green roof on my shed?

Thanks to the easy-to-install design of our sedum roof trays, they can be fitted on most flat roof sheds and some roofs with a shallow pitch to form small green roofs. We wouldn’t recommend using this product on roofs with a pitch of over 9.5° - this rules out most classic sheds with gable roofs that have a 15° pitch. Anything over 9.5° will require additional design features to hold everything in place. 

With many shed styles and pitches, it’s important you don’t take any risks with your green roof. For anything over a 5° pitch, we would also recommend installing a secure perimeter wooden upstand with a gap at the bottom. Please contact our technical team for further details.

You also need to ensure that the roof has a suitable primary waterproofing layer. This could be roofing felt or bitumen shingles. We would always recommend laying a protective fleece layer underneath the trays as a precaution to ensure you don’t cause damage to the primary waterproofing layer. If your shed roof is metal or cement corrugated sheets, it may still be possible to achieve a sedum green roof but get in touch with us to discuss the details.  

If you’re creating a sedum roof system using a roll-out drainage membrane and substrate layer, we wouldn’t recommend installing this on corrugated roofing. Contact our technical team if you have any questions about the suitability of your shed’s roof.

Can my shed support a green roof?

Sedum is lightweight. However, if the substrate level is deep, it can mean your green roof weighs a lot. In the case of sedum trays, this is limited to a set weight each time, which makes planning your green roof even easier. 
For every 1m² area of sedum tray, the fully saturated weight is approximately 59 kg. That’s 59 kg/m² or 13 kg per individual tray. This is considered lightweight when compared to traditional sedum blanket and substrate systems. If possible, check with the shed manufacturer that the shed can withstand the extra weight. If you have enough internal space, you can build a frame within the existing shed frame to further strengthen the roof structure. 

Advantages of a shed roof garden

Green roofs can benefit the structure of your shed and be beneficial to local nature. Sheds are likely to be in more exposed parts of your garden. You’re also less likely to notice damage or wear and tear, particularly in the winter months, due to spending less time in them. Anything that can help protect the structure is a good idea.
Just some of the benefits that a shed green roof provides include:

• Acting as a natural insulating layer - this keeps the interior warmer in winter and cooler in summer. This is a huge benefit if you’re spending time inside it, as it will make the space more comfortable. If you heat your shed then it will also help reduce energy costs. It will also help keep the interior in better condition in the colder months.
• Supporting wildlife - green roofs provide habitats and food for a variety of different wildlife such as insects and birds. 
  Looking attractive - a green roof looks great. Installing one on your shed will also help it blend into the natural environment.
• Soaking up rainwater - by absorbing rainwater, it will help alleviate runoff into your garden.
• Increasing the roof’s lifespan - sedum can help your roof last longer by protecting it from the elements and absorbing UV light - increasing its lifespan dramatically.
• Improving air quality - sedum plants absorb CO₂ and particulates, improving the quality of the air around you.

PermaSEAL Sedum Trays include 16 different varieties of sedum that will ensure a flourishing roof all year round, and provide all the listed benefits without interruption. Sedum is a hardy plant that doesn’t need much maintenance. Our trays automatically retain the right amount of water, so, once installed they need very little looking after. 

See our guide for more information on looking after your sedum roof.

How to make a green roof on a shed

Installing a sedum green roof on your shed using our tray system is easy. 

You’ll need:

• PemaSEAL Sedum Trays
• PermaSEAL PRO Protection Fleece
• A stable and safe ladder to help you confidently reach the roof of your shed
• A wood saw

Placing the trays can be done by one person as they are light and manoeuvrable. To get your garden shed green roof up and running:

1. Begin by rolling out the protection fleece over the roof.
2. Lay out the trays on the top of the fleece. They should be securely slotted together to ensure they’re safely held in place.
3. If necessary, use a wood saw to cut trays to fit. Place so the side you’ve cut is facing inward.

Once you’re happy with the layout, you’re done! Your green roof is ready to go and should just need watering during prolonged dry periods (of over two weeks).

For a more in-depth look read our guide to installing a sedum green roof.

Sedum roof cost per m²

NOTE: All prices are correct at the time of writing but are liable to change.

It takes 4.5 of our trays to cover a 1m² area. We deliver them on a pallet that can accommodate 45 trays with a flat £80 delivery charge. This charge is built into the price of the first tray. So, one tray will cost £96.50 and each additional tray is £16.50 (Ex VAT), up to a maximum of 45 trays. Using a 3 metre x 3 metre shed as an example, you’d need approximately 45 trays (includes a couple of spares) at a cost of £822.50 ex. VAT for the sedum trays delivered.

Permagard - sedum green roof tray suppliers

Our sedum roof trays are designed to be simple to install and easy to look after. We supply everything you need to get your new green roof flourishing:

• PermaSEAL Sedum Roof Trays - your all-in-one green roof solution.
• PermaSEAL PRO Green Roof Protection Fleece - to protect the primary waterproofing layer.
• Osmocote PrePlant Fertiliser - to keep your sedum plants healthy.

If you’re looking beyond a simple shed, we can help you create a green roof system for any structure. 

Get in touch

If you have any questions about planning and installing your shed green roof or want to know more about our green roof products, get in touch with our friendly team by calling 0117 982 3282 or email us at [email protected].