Roof terraces are becoming increasingly popular for town and city dwellers who want to make the most of their homes. As well as providing additional outdoor living space, did you know that a roof garden can reduce your energy bills, cut noise pollution and create a haven for wildlife?
If you have outdoor space that you wish to turn into a roof terrace, a good garden designer should be able to help you visualise what it could look like, scope out what’s possible, and make your dream of a rooftop garden a reality. For straightforward projects, assured gardeners and/or DIY builders may not even need professional assistance. However, before you start getting carried away, there are a few important questions to consider.
1. Is my roof suitable for a roof garden?
Do you have an area of flat roof that you think would make a spectacular roof terrace? The existing surface may not be designed for loadbearing (so don’t step on it just yet) but this could potentially be resolved by reinforcing the floor. Especially on older buildings, there may be limitations to the weight and loading you can put on the roof timbers below, so make sure you choose materials and planting designed to minimise the stress on the roof structure. You will also need to create access from inside the house, perhaps by changing a window into a doorway, or with a bespoke solution as can be seen here.
2. What if I don’t have a flat roof?
If your roof is pitched, there’s no need to give up on your dream of a roof terrace just yet. While a flat roof is more straightforward (and cheaper!) to work with, it is possible to create a suitable flat outdoor surface by building up an external wall. You could also alter the roof design to incorporate an inverted dormer. The result looks like a chunk has been taken out of the roof to create a lovely, private outdoor terrace – see below. Be warned that this is not a job you should attempt yourself. Ask an architect and building surveyor for their professional opinion.
3. How large will my roof terrace be?
Roof gardens come in all shapes and sizes, and it’s not necessarily the case that large equals better – it all depends on the individual design and its execution. The maximum size of your outdoor terrace will be governed by the available floor space. Check if the terrace is too exposed and likely to be overlooked, or if it overlooks a neighbouring property. You may need to bring back the boundary line as much as it is necessary so as not to cause privacy issues. You can also use clever screening to maintain privacy, for example by using opaque glass panels, fencing or hedging, as is shown in the London rooftop design below.
4. What permissions do I need to obtain?
Your roof garden project may or may not require planning permission. Ask your architect or local planning officer and make an application if needed. Your surveyor should also advise if you need a Party Wall Agreement if the works affect a joint “party” wall or structure between your and a neighbouring property. No building work should start until the necessary consent has been granted. Even if no permissions are required, it is always a good idea to keep your neighbours fully informed of your plans. Take it as a goodwill gesture that will ensure they are less likely to make a complaint.
5. How do I plant my roof terrace?
Successful planting schemes can be used to achieve a green space high above ground. Bear in mind the aspect of your roof garden. Sheltered, sunny spaces can work well with Mediterranean plants including olive and orange trees. Exposed areas are better for grasses and bamboo that cope well in windy conditions. Effective irrigation and screening will help mitigate some of the environmental challenges. For container gardening, choose plastic or fiberglass plant pots, and mix regular compost with perlite or clay granules to help with water retention while minimising the weight on the roof.
6. Which furniture and accessories work best?
If you wish to transform a hard landscaped roof terrace into a tranquil oasis or an exciting place for entertaining, simply select a planting scheme of your choice and add a stylish seating or chillout area. Choose lightweight, flatpack, easy-care furniture that you can quickly assemble on the terrace. Look for outsized shade sails to protect sunny terraces during the day, and an atmospheric firepit-cum-barbecue to warm you during colder evenings and grill your dinner at the same time. A water feature adds a nice touch too.
7. How can I get the right ambiance on my roof terrace?
The key to creating the right atmosphere at dusk and after dark lies in good lighting design. Don’t make the mistake of considering lighting as an afterthought. To get the best results, this should be a central element of the whole garden terrace design process. Make sure the builders install circuit breakers and light fixtures and fittings that are suitable for outdoor use, and ask them to add some waterproof power sockets for additional lighting fixtures or appliances.