For many, having a garden on their roof (or living roof) would be fantastic but so many unanswered questions stand between a homeowner’s dream and making it a reality. Will the roof safely take the weight? How do I plant on a roof? How will they be watered? What should I plant? What are the pitfalls?
Every roof garden is different and each conversion comes with its own challenges and considerations. In this article we hope to share some tips and explain the considerations to take into account when planning a roof garden.
Roof Garden Planning
- Make a rough sketch of what you want. This should include details of how you expect it to be used.
- Get your flat roof and substructure surveyed. A green roof can weigh in the region of 150KG per square meter and many home flat roofs would be unsafe with such a load. Making sure your project doesn’t bring the house down is essential and only a qualified inspector can give you an answer you can build on.
- Plan the garden’s requirements. To fully understand how the roof must be built you need first to work out the needs of the garden that will rest upon it. This should include drainage, watering, types of plants and how/where they will be planted. In addition to the practical considerations, there are hundreds of potential details to consider in the style and character of the garden. If you’re laying turf or planting right onto the roof surface, your roof will need a filter layer under the earth and a drainage layer below that on top of the flat roof itself. Ensuring your preparation below ground suits your ambition above ground is essential to avoid big issues developing in the long term. Taking the advice of a creative landscape gardener or roof planting expert can help the garden plan turn out just right. The garden plan should show the location of all features and make a good estimate of the weight of the plants, substrate and furnishings.
- Plan the outline of the building work. Take your survey and talk to the right flat roofing and building firm. Form a plan to build the roof surface and any structural reinforcement required plus any plumbing, drainage and safety rails required. You roofer will help you pick out the right roofing material and insulation, GRP Fibreglass is a popular choice for its strength and durability and is available at a range of thicknesses to suit garden roofing needs. GRP is great for gardens as it can be coloured to help create the right style. So once you’ve worked through your requirements with the roofer you will get an estimate and coupled with the estimate from the garden planning a picture of what it will cost to turn the dream into reality.
- Apply for planning permission. In most domestic situations in the U.K planning permission will be required to build a garden on your flat roof. This can be a daunting and troublesome process but in general if your plan is sound and your idea is good, you can obtain permission relatively easily. A roof garden is generally viewed as an enriching feature in any neighbourhood and most councils look upon them favourably.
- Put your team together and make a plan of execution. So you’ve got planing permission, a quote for the building and an estimate for the garden. Now you can bring this together and make the final plan. A good flat roofing firm will take a central role in project managing the building and roofing work and may be engaged to help deliver the ‘landscaping’ part of the job. When making your plan it’s wise to check the availability of all resources your project will need and consider what you would do if any given product did not arrive on time for your project. A well laid plan for a large project needs a few backup plans and some efforts to minimise risk if it’s to go smoothly.
- The construction, if you’ve done a good job of all previous steps the plan will come together nicely in reality and you’ll see your garden take shape as you’d hoped. It’s a good idea to talk to your contractors every day they work for you to keep in the loop about progress so if there are small delays you see them coming and can plan around them. Typically the homeowner will need to section off some space in the garden to store and then assemble garden furniture and prepare plants to be hoisted up to the roof.
- Once your project is finished it’s time to wait for a sunny day and get out to enjoy it for the first time. At JustFlatRoofing we will come back some months later to give our work an inspection to check everything is just right and to see how the plants are doing.
Image credit – Jeremy Bittermann
Thinking of having a flat roof installed?
A roof garden can be a sizeable project but if handled properly it can be a very smooth and rewarding experience in the building and deliver years of enjoyment in the future whilst adding significantly to the value of your property. At JustFlat roofing we’re delighted to work on these projects and have years of experience in delivering interesting and complex flat roofing projects, so if you’re dreaming of a roof garden, why not give us a call.
If you need some inspiration, The London Sky Garden situated in an enormous glass dome on the roof of one of London’s towers in the City, it’s FREE to book a visit and is an example of roof gardening on an incredible scale. Find out more here
(Header image source: VUW)