Creating a Green Roof on Shed or Garage

green roof

What is a Green Roof?

Green roofs are increasingly popular features atop houses, sheds, and garages across Britain. As well as providing unconventional and unexpected slivers of beauty amongst mundane architecture, they help to improve biodiversity in urban areas, attract local wildlife, offset carbon emissions, and even provide insulation and flood protection for nearby structures. 

There are two types of green roofs. Intensive roof gardens tend to be created on a large, complex, and commercial scale (think rooftop gardens perched above city skyscrapers). Extensive green roofs, however, are much better suited to your garden shed or garage. They are low maintenance, uncomplicated, and lightweight by design.  

How to fit a Green Roof?

Structural Integrity and Specifications

You will need to check out the structural integrity of your shed or garage first, to ensure it can support the extra weight of the garden. Of course, flat roofs are preferable, but any slope of fewer than 30 degrees is suitable for a green roof. If your chosen roof is slightly sloped, you may need to build a supporting frame to prevent the garden from slipping down the roof, particularly after heavy rainfall. 

Your roof will need to receive both adequate sunlight and rainfall for plants to thrive, and you will need to access your garden once or twice a year for essential maintenance, so ensure you have a safe way of getting up on top of your shed or garage. 

Layers 

Extensive green roofs need to be constructed in layers. Firstly, they require a waterproof layer or membrane to protect the structure beneath. This could be an existing layer of bitumen or similar, or you may need to install something more hardwearing.

Next, you will need a root barrier to protect the structure from root damage. A polyurethane sheet or weed-proof fabric should do the trick. It is crucial to install a drainage layer to prevent your roof from becoming waterlogged. Drainage mats are readily available to purchase in a variety of size specifications and usually feature capillaries or perforations which allow water to flow freely.

Next, you will need a layer of lightweight, nutrient-rich, free-draining substrate as the growing medium for your plants. This should be between 50 and 100 mm deep. Finally, you can install your vegetation or sow seeds over the substrate layer. 

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Suitable Plants

The idea is to create a garden that only needs tending once or twice a year, to weed, feed, replenish any dead areas, and check on the drainage system. Occasionally, during droughts, plants may require extra watering. Low maintenance and shallow-rooted plants are the keys to success here. Try to mix your species, as this improves biodiversity, adds interest, and prevents disease or nutrient deficiency.

Sedum blankets are by far the most commonly used vegetation in roof gardens. These hardy succulents provide excellent coverage with minimal food, water, and sunlight requirements, whilst providing pretty blooms. Native wildflowers are another great choice for roof gardens, as they require almost no maintenance, will attract plenty of local wildlife and will provide a stunning, colourful display in the summer months. If your shed or garage roof is not very easily accessible, you could even consider creating a kitchen garden by growing shallow-rooted, hardy herbs such as Rosemary, Chive, or Thyme.

When the final stumps are pulled…

Sign on green grass

Most cricket squares start to look tired by the end of the season, especially if the weather has been going through extreme phases, something that seems to be happening more frequently of late.

In order to ensure that the pitch is in the best possible shape for next year’s season, preparation and renovation are essential, and as important as team training and sessions in the nets.

As anyone who visits other grounds during the season will know, many pitches are often lacking in terms of pace and bounce, and it only gets worse with weeks and weeks of play. 

This is often caused by the failure to carry out a regular thatch removal regime (or ‘organic matter’ as its called these days) but one of the main reasons is skimping on the application of top dressing, either during repairs, or at season end. 

The latter is understandable. Many clubs are struggling to survive – especially with the cancellation of the 2020 season – and let’s face it, top dressing is expensive, and applying it is hard work, so missing it for one year won’t hurt, will it?

Talk to a dozen different grounds persons, and you’ll probably get twelve different versions of how end of season renovations should be done, often depending on budgets and motivation.

The fundamentals of end of season maintenance are to try and get the pitch levels spot on, and to rejuvenate the layer in which the sward is growing – known as the rootzone. 

It may already be too late by the time you read this, but it’s worth planning ahead to try to book a hired aerator and a scarifier, along with a spreader if you don’t already have these. Decent sized machines can take a lot of the hard work out of the whole operation but remember to off hire promptly (and get an off-hire confirmation!)   

Talk to an advisor from your local cricket board – they’re usually as keen on getting good cricket grounds as the players are. Ask them to take samples using a core sampler. Consider sending samples away for analysis, this will provide all sorts of vital information, including thatch (organic matter) levels, toxicity, pH levels, soil nutrient levels and soil classification.

So we’ll all be doing something like this:

  • Close mow the table diagonally in both directions
  • Scarify the table thoroughly. Ask your advisor for their advice on which sort of tines to use and how deep to go.
  • Water the table thoroughly. 
  • Carry out an aeration programme – again, an advisor will be able to advise on hollow or solid tines, how close the tines should be etc. This will give the seed* a better chance to root properly as some of it will go down the holes. 
  • *Ah yes, the seed. A blend of dwarf perennial rye grass seeds (Lolium perenne) seems to be preferable these days to the old school bents and fescues we used for so many years; much more resilient too. You’ll need to apply this at around 30 grams per square metre. 
  • Mix autumn/winter fertiliser with some top dressing, ensure good coverage but don’t overdo it. 30-35 grams per square metre is the norm but it’s worth checking with your supplier.  
  • Water the table thoroughly. Again.
  • Aerate the table again, as above take advice on which size and type of tines to use. 
  • Once you’ve done all that, top dress the table with a good quality screened loam, you’ll need roughly 350kg per strip, call our sales team on 01342 893174 or email info@dev.solutionsfinder.co.uk to find out how we can assist with supplying this for you.
  • Lute the table thoroughly to maintain levels, followed by drag matting several times until the visible loam has mostly dispersed.
  • Put the ropes and barriers back up to keep unwanted visitors off.
  • Enjoy a suitable hot or cold beverage of your choice and congratulate yourself on a job well done.

So that, in a nutshell, is how to put your cricket table to bed for the winter. You’ll probably need to just top the grass off from time to time, but this will of course give you time to do all those jobs you’ve been putting off for the summer.

And keep in touch with your advisor, they are there to help, and will probably advise you on an ongoing maintenance regime. 

Remember – fail to prepare, prepare to fail.