The interest for urban rooftop terraces makes a dream proposition for architects and designers who can see the potential for establishing flexible and versatile outdoor environments that can be utilized for nearly anything and this can become an easier task if one takes informed decisions and keeps certain key factors in mind. Senior Project Lead, Euan Taylor, has come up with a list of few Dos and Don’ts of designing your next roof terrace system.

Do’s

• Preserve the View: The view from a rooftop living space is one of your most valuable amenities, so all design decisions must preserve and maximize it. Design choices must reflect and enhance this asset – for example, changing a solid wall to a ‘transparent’ railing or glass balustrade can greatly enhance the view, and borrow space to make your project seem larger but if there is an eyesore, using planting and screening may be the perfect solution for hiding an undesirable segment, whilst retaining the view.
• Enhance Privacy: One of the main advantages of having a rooftop or terrace is that you have a wide view from all sides but in some cases, this turns into a burden, if your rooftop is presented to the perspective on all the meddling neighbours or you have a terrible view from that point, making green walls and hedges can totally change a rooftop terrace into a mind-blowing outdoor area that can even resemble a garden. For this, make tall and thick vegetation around all the corners that will offer you absolute privacy and an ideal setting for outdoor living.
• Mitigate the Environment: When you invest a lot of money in an outdoor living space, it must be comfortable for you and your plants in as many seasons as possible. In the colder months when you live indoors, the planting and decor should make this space equally as attractive to look at through windows. A big challenge is to put into place elements that mitigate your unique set of climatic challenges with attractive components that work well with the interior style. Some of the typical problems include south and west facing units where afternoon heat and full exposure in the summer months can be overwhelming. Here you will need seasonal shade. Those units located in wind corridors where gales rip through the spaces between large buildings will need protection. Metal wind screens or selection of plants that tolerate this buffeting may be essential and can still be made very visually pleasing.
• Think Future: One of the hardest challenges when working on terraces and roof landscapes is being able look into the future – this is critical for the ongoing use and maintenance of your terrace. This is an outdoor environment, subjected to more extreme conditions than ground level – rain, wind, exposure to direct sunlight and heat, as well as a cold winter all have an impact on both the finishes used, and the planting. Select flooring that is non-porous – this means algae cannot grow and preserves your terrace from looking ‘old and damp’ (and preserves you from slips, of course). Natural timbers can look great when new but remember to continue staining and preserving the timber to keep it looking great – also try to keep away from large planks of timber, as these tend to warp and disfigure easily.
• Minimise the Impact on the Building: A roof terrace is named, believe it or not, because it sits on the roof of the building. This can come with a variety of different complications, but the two main challenges to impact the building is waterproofing and weight-loading. Waterproofing is a delicate layer which you certainly will not want to penetrate (or least possible), so make sure you choose a self-supporting system which does not need fixing down. On older buildings in particular, weight can also be a significant problem to overcome – try to keep away from solid build-ups like concrete, which has unnecessary weight. With a clever modular support structure, you can save fixing into roof with no extra weight, all without any detriment to the design.

Don’ts

• Forget about the Wind: Wind is a common problem in rooftop gardens. Numerous plants can adapt to it however you may require some haven on the off chance that you need to appreciate the space the entire year. Unless there is protection from surrounding buildings, solid windbreaks are not a good idea as they block out the view, plus the wind stress on fixings is high. Instead, choose a permeable trelliswork, which is then fixed to a pergola. Taller wind-tolerant shrubs offer some protection. Think of them as a living screen. Tough evergreens such as Olearia, Phormium, Pittosporum and Spotted laurel in planters would be a great wind barrier. Bamboo merits attempting as well, besides on windy rooftop patios as its enormous leaves influence a lot in the breeze, which implies the roots will move about and the plants will not establish in their new pots.
• Rush the Planting Design: As discussed above, plants will have to be very tough to cope with difficult conditions found on rooftops. They will probably have to be tolerant of high winds and drought as well as strong sunshine or deep shade, depending on the aspect. Thick evergreen plants are useful for all year intrigue and most have thick, reflexive leaves, which keep them from drying out rapidly. Griselinia, Garrya, Viburnum tinus, Escallonia, Euonymus, Fatsia and dwarf fan palms are ideal and give asylum to brilliant yet intense perennials, for example, globe thorns, day lilies and Heuchera tucked under them. Alpines, whose common living space are clifftops and mountains, need little water and can manage extraordinary presentation to serious daylight and strong winds.
• Forget about Acoustics and Sound: Engineers know that sound travels upward. The clamour of hefty traffic can be stronger a couple of floors up than it is on street level. This and the overall commotion of city life can ruin the feeling of serene division you are attempting to accomplish in the living space. This places a high value on the acoustics of the terrace. As above, a dense evergreen plant is a good acoustic barrier, but the best form of acoustics is to ‘mask the sound’, rather than hide it - the sound of water is a very effective masking device, with wall fountains being the most space saving style. They stand at the edge of the space against a wall or may even be hung upon the wall, asking for little to no square footage to be devoted to its base. Scientists put it best: “the sound of water can induce a flood of neurochemicals that promote wellness, increase blood flow to the brain and heart and induce relaxation.”
• Go Cheap: As with all things we buy, we should look at the value of the terrace before we look straight to the bottom line. A roof terrace can add up to 25% to the value of your building (Knight Frank Property Agents, 2018), so it will require significant costs to truly realise the return on investment. A terrace, like anything with real estate, can vary hugely in cost, from £10k to £10m, so make sure you use the correct materials, utilise the expertise of architects and engineers, and finally, do not just cut costs for the sake of it – whoever uses the terrace will know about it in 5 years’ time.
• Use Hybrid Systems: The use of multiple support systems tends to lend itself to extra unnecessary challenges, particularly when introducing different finish surfaces, such as artificial grass, tiles, and resin-bound gravel. If, for example, you are laying artificial grass on a ‘typical’ build-up of concrete slab and insulation, this does not interface well with tiles or decking, as well not working with the drainage of the roof. Invest in a system that can support these multiple finishes, whilst still doing away with the need for a solid build-up and keeping the overall weight of the terrace as low as possible.

We encourage you to keep these points in mind when designing and constructing your next roof terrace system. Kinley’s team of experts are always available to offer every bit of advice and guidelines when designing and installing our award-winning roof terrace system. Email [email protected] or give us a call at +44 (0)1580 830688. There is much to learn in our CPD presentations and you can book your seat by sending an email to [email protected].