by Jamie Dobinson of Crafted Landscapes
Introduction - How to build a green roof refuse store
Green roofs can turn an average project into something exciting and environmentally positive, creating an attractive focal point that entices wildlife to your garden.
Not many people enjoy taking out the rubbish, So why not build yourself a beautiful refuse store to hide the unsightly monsters away.
CL undertook this Project during the summer of 2021, as part of a wider scope of works, we always intended to share the process in the form of a blog, so here it is.
This article focuses on a Refuse enclosure that has the added feature of a sedum roof. However, The principles could be used on many other areas around the home and garden, for example -
Garden shed
Porch
Log store
Flat roof extension
Balcony
Summer house / garden cabin
Bicycle shed
Ten reasons Why
Environmentally positive, capturing carbon
Smartens your property by creating an attractive focal point
Entice wild life to your garden, support native plants / animals
Learn and experiment with drought tolerant plants
Rain water management
You may be short of garden space so this offers a new planting bed
Noise and thermal insulation (if used on a habitable room space)
Increasing bio diversity, By creating new habitats
Potential for food production (Herb bed)
Overall, It looks aesthetically beautiful ! brining a sense of well being to the users.
Green Roof Plant types
What plants can you grow?
Put very briefly, below are some of the plants that may be suitable for your DIY project
Succulents & sedums
Flowering herbaceous and alpines
Grasses
Native wildflowers
Smaller bulbs
Annuals
Moss
Herb garden
Before Building
Consider your options regarding the location of the refuse containers, where is the most practical and accessible location to house this new enclosure? You Need to consider yourselves, in addition to the waste collection lorries, More importantly think about the plants you will grow and the conditions they require.
The Design
The store will be designed around the size of your bins, So measure each section and work out how many units require housing, Generally in the UK, you would have three bins, (standard waste / Recycling / garden waste). You may want to also consider creating a space for logs and kindling, or even a secure location for parcels to be delivered.
Make sure you add plenty of additional space between the bins and above them, this will ensure you can easily wheel them in and out without hassle.
The roof depth will be determined by the choice of plants and what soil strata they can tolerate,
Design the project, this could be done simply by a sketch on paper or more accurately using CAD. It would be useful to create a floor plan, elevations, and cross section. this will help ensure you order enough timber and not be wasteful. Saving time, money and the environment.
Using the dimensions of your plan, mark out onsite the location of the bin store, this can be done using a marker spray or string lines. You need to ensure you have plenty of working space around you, so clear any overhanging shrubs / branches.
The Foundation Base
CL constructed this bin store using a timber frame, so it was important to house the enclosure on a solid and dry foundation. Now that your location has been cleared, excavate the vegetation and topsoil to a minimum depth of 100mm or 4inches, levelling out the existing ground if required. A base can then be installed using Compacted Type 1 MOT, or concrete. This should be built 100mm on all sides, larger than the Bin bay footprint.
Timber frame
Now that you have the base and size, you can begin constructing the timber frame, CL have used treated soft wood timbers, and these are 4x2 inch in size, We have simply pre drilled and fixed the studs using timber drive screws, NOTE all the heads of the screws have been sunken to ensure the cladding will not coincide. Any cut timbers should be treated using a timber preservation oil. CL built the box frame independently as we had restricted space in the fixed location, Once the Main frame was fixed we lifted it into its final position, (pre cladding / roof and doors) to limit weight.
As mentioned earlier, this particular Bin store was part of a wider project, so the landscape around it has been designed to merge with the Unit, hence the side cladding and lower oak retaining wall actually forms part of the construction, Your project may be an independent structure which is certainly easier to construct, you would just clad each elevation the same.
The roof structure
Please be extra thoughtful when building the roof, this section will support the planting, the soil and drainage material is surprisingly heavy, so be certain to over specify the roof joists, in this example CL have used 4x2 inch timbers at 300mm centres. You also need to ensure your roof has been installed with a generous fall / gradient, To allow water run off.
Once the roof has been framed, you will need to screw a timber sheet over the top to spread the loading, this could be 18mm ply or OSB board, we then installed a waterproof liner, and on top of that, a weed membrane to ensure the plant roots do not penetrate the waterproof liner. I have included a detailed drawing above Image 3 for further information on the build up of this.
The green roof will need a minimum of 75-100mm of soil and drainage to allow for the roots to establish. You can see from the below image how we have built up the edges using 25x50mm battens and a gravel board edging. Please Note you will need to ensure there are drainage outlets to allow water run off, you can do this by simply drilling the rear timber gravel board.
The cladding
There are a few things to consider when choosing your cladding, number one is aesthetics, Always be mindful of your surrounding context, are you in the countryside or city location, what is the local architecture like, Is your home modern or rustic? Then you need to think about ventilation, Bins tend to smell foul, So ensure you keep air gaps around the cladding, it will not matter if some water enters the store. In this example we have used a 25x50mm Treated timber batten, Spaced at 10mm intervals. We think this looks rather smart and goes well with the lower Oak wall, eventually all the timber will silver down to a more natural finish. Alternative cladding could include waney edge chestnut, vertical timbers, old floor or scaffold planks, even decking or pallet wood could be upcycled.
The doors
As you can see in the above photo, the doors have been installed and we have framed them using a 3x2 inch treated timber, in addition to using galvanised metal hinges. The below photo shows the doors clad and finished using a few trims and furniture.
Planting the green roof
The fun part ! In this particular project, the client wanted a low maintenance but wild life friendly planting arrangement, You may want to use wildflower grasses, or something more creative, CL do not specialise in horticulture and soft landscaping / planting so we contacted a Local nursery whom helped us specify what would work well in this specific location and aspect. Be sure to Ask questions about the soil that would be best suited for your planting selection. As you can see from the below photo we added 10 % drainage material to the soil (2-5mm horticultural grit)
If you are on a budget you could always buy the sedum roof seeds, or plugs, below links for information.
We have planted the sedum roof and spaced out generously, below are some of the species we have used and are suitable for this type of green roof. Planting green roofs is a very specialist topic in its self, and there are many things to learn, As with all planting its best to give something a go and see what works in your particular location, just remember you require drought tolerant sedums that can cope with shallow substrate roofs.
Sempervivum tectorum, the common houseleek
Deschampsia flexuosa, commonly known as wavy hair-grass
Leucanthemum vulgare, Ox-eye daisy
Sedum Rupestre
Sedum Hispanicum
Sedum Fosterianum –
Sedum Anglicum
Sedum Acre
crocus
After planting, we added a layer of pea shingle stone, this was for decorative purposes in addition to help with weeds and drainage for the drought tolerant plants
Project complete
So now the plants are in their new home, the project is complete, Insert your bins, and look forward to taking them in and out, its a pleasure to see how this project has developed and the plants matured over time, below are a few photographs the clients have sent me showing the progress over the first few years.
In Summary
Measure what will be stored i.e. Bins / logs / bike / parcels etc
Decide what plants you would like to use and research their requirements
Determine the best location
Design & determine the overall height / width / style of finish.
Order your materials
Mark out the area that will house your new store
Install foundation
Construct timber frame
Clad the sides
Fix the doors
Build the roof
Purchase your plants
Plant the sedum roof
Enjoy taking out the rubbish !
NOTE
If you would like a full pdf list of materials and tools required for the project feel free to email me - jamie@craftedlandscapes.co.uk
Useful Links
Conclusion
Thank you for reading my HOW TO BUILD a Green roof refuse store blog! I hope you have found it useful, and perhaps inspired you to build your own! For similar HOW TO projects, feel free to come and visit my website - www.craftedlandscapes.co.uk
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I hope you have found this HOW TO guide easy to follow and informative. If any of the steps are unclear and require further clarification please feel free to contact US.
References
All of the photographs used within the blog are work of Crafted Landscapes, The clients have given permission to use the Images for this article. The drawings are copyright of CL & have been sketched by Jamie Dobinson. Please contact or credit us with a reference and link back to this source if you would like to reuse any content. Any drawings should be used for Illustrative purposes only.
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