Room at the top? Plan a roof garden

Press, 6 May 1980, Page 14

Room at the top? Plan a roof garden

LANDSCAPING AT HOME

By <

Gilbert Brakey

Rdof gardens could be used in a number of different ' situations. Examples are a reasonable area of balcony; an extensive terrace on a hillside home or in an apartment-style building; a two-storey house; or, the roof top of some office and shopping buildings. The roof garden can therefore range in size from a very small area of a few square metres to an extensive area of many square metres. The garden may be fully open to the natural elements, partly enclosed, or fully enclosed. With adequate shelter otherwise wasted areas could, 'be used as an outdoor cafe, restaurant or simply as a sunny and warm place for weary shoppers to recuperate before continuing on their way. At home, particularly if vou should be in the process of planning a new building with an upper storey, it may well be possible to incorporate one or more spaces for a roof garden. What, then, are some of the basic requirements for any roof garden space? The area selected must be structurally strong enough, to withstand the additional weight you propose to place upon it. If using raised planters, for example, filled with earth, it would be advisable to consult an engineer. Normally, however, there should be no real problems as far as the weights imposed are concerned. The next and most important aspect is to ensure that the area is completely' impervious to water as you hardly want to have moisture finding its way through to the rooms below. Satisfy self about this detail very carefully as it can be a most expensive problem at a later stage. Provision should be made for the run-off and collection of both storm water and ’ artifically applied water. Ensure that the water has more than one way to be removed in case a blockage occurs. • The floor area can be paved over a water-tight base by using such materials as tiles, brick, small concrete modules, timber decking or wood bricks. The size of paving module chosen should be in keeping with the space it is to occupy. This really also applies to the paving colour and texture. Enclosure of a roof garden may be necessary if winds are likely to be a problem. If outward

views are important toughened glass panels can be used. Where outward views are unattractive or nonexistent use attractive screens or enclose the area within the house walls. An overhead structure may or may not be required. If it is, does it need to be glazed or can it be left as open beams with perhaps a light vine cover? It should be remembered the enclosure may well be required for privacy as well as wind protection. A house on the hillside may encounter this peculiar problem. Planting will in most instances play an important role in the design of the roof-scape. The type of plants chosen will be dependent on the degree of exposure and general micro-climatic influences within the space to be used. The other factor requiring careful attention is the growing medium and its container. Plants may be grown in individual pots or tubs and placed within the area as a specimen or in massed groupings. Alternatively, planting beds are provided by the use of raised planter units or larger containers specially built into the floor structure. The planting itself can range from exotic, wellprotected, indoor plants to the hardier outdoor

; species. The choice ranges ; over shrubs, climbers, vines, flowers, and small ; trees. The root system is a : prime consideration, . and ; should naturally be i fibrous in order to be able to grow within a limited space. Do not rule out the possibility of using grass lawns, as they can be an i effective part of the floorscape. Id fact, turf is an ex* cellent insulator and in certain countries overseas has been used on. suitably designed roofs of buildings to control the extremes of winter and summer temperatures. The growing medium for plants needs to be well, drained and nutritious. The U.C. (University of California) mixture is ideal as a growing mej dium. But there are alternatives to actual soil for the growing medium — for example, hydroponics may be one system worthy of consideration. - A watering system — of which there are many types available — should be an integral part of the project and not left to be an afterthought. Consideration should also be given to the use of lighting for night use and visual effects. Outdoor furniture could be used to provide a place to relax or dine out under the heavens. Sculptural or water features may well complement the decor of a roof garden.