Terrace Garden / Green Roof

Garden roofs explained in detail along with waterproofing and some examples.

1. Roof Garden Green roof is an environmental, social and economical use of the building roof.

2. Roof garden A roof garden is any garden on the roof of a building. Besides the decorative benefit, roof plantings may provide food, temperature control, hydrological benefits, architectural enhancement, habitats or corridors for wildlife, and recreational opportunities. The practice of cultivating food on the rooftop of buildings is sometimes referred to as rooftop farming.

3. History of roof gardens The first known historical reference to a roof garden above grade is for the stone temples in the region of Mesopotamia. Civilizations in Mesopotamia built roof gardens thousands of years ago on the landings of Ziggurats, or stepped pyramids. The plantings of trees and shrubs softened the climb, provided shade and relief from the heat

4. The next known successor to the roof gardens are the Hanging Gardens of Babylon built by the Persians around the 500 B.C ( Weiler & Barth, 2009). The roof gardens along with being a visual delight cooled the hot landscapes and provided greenery

5. The World Exhibition in Paris 1867 was one of the first demonstrations of a planted concrete roof in Western Europe In the Middle Ages and Renaissance, there were additional demands from the roof gardens and that was to meet the demands of Christian ecclesiastical architecture and wealthy families of the era (Osmundson, 1999). Palazzo Piccolomini, Pienza, Italy

6. R oof garden The first and most important step involved in making terrace garden is to identify the area of terrace where you plan to build a roof garden. the roof on which we are designing garden should be strong enough to carry the weight of garden . The roof should not have any leakage of water in roof and it should have effective drainage system . Roof garden can be made on half of terrace leaving a patio to make a sitting place.

7. Water proofing of roof Next step is water proofing the roof slab to prevent the seepage in the roof. A proper water proofing treatment should be done before building a roof garden. Chemical based water proofing treatment is more effective than covering based water proofing. D rainage pipes should also be laid over the roof slab. A water proof covering with the thermoplastic or rubberized sheeting should be installed. Filter sheet is also necessary to drain off the moisture from the roof slab.

8. Steps to be followed. STEP 1: waterproofing Cutting and laying of liner ( waterproofing membrane) Applying solvent Fixing liner Leakage test by keeping water for upto 48hrs STEP 2: Installation of drainage cells STEP 3: Laying of geotextile STEP 4: Filling planting soil Filling of sand, soil and coco pit Mixing of planting soil Leveling STEP 5: Planting plants

9. GEOTEXTILE LINER DRAINAGE CELLS

10. Soil depth is at least 0.25 meter W eight for intensive green is approximately 244.1 kg/m²

11. Gardens with surface area less than 100sq.m

12. Plants cool the air around the rooftop through evapo -transpiration and shading from the plant cover. Evapo -transpiration is the sum effect of evaporation and plant transpiration from the surface of the vegetation that results in the cooling of the surface as water evaporates from it . Reductions of up to 90% in solar gain on roof area shaded by plant cover compared to un-shaded location can be achieved and indoor temperature decrease of 3-4˚C (6-8 ˚F) may be attained (Peck, 2008).

13. 2 x 200mm thick concrete slabs, each 4 metres maximum span, on load-bearing perimeter walls of 300mm aerated concrete blockwork and two internal columns running from ground to roof (key location points for walls in the flexible internal apartment layouts). A 400mm high concrete upstand surrounds the slabs. Drainage outlets placed at 3 – 4 metre intervals were reduced in number in the final construction. Two layers of bituminous, heat-welded waterproof membrane were applied to minimise potential for leaks. 19mm of sand was spread over the bituminous layer as a bed for butt-jointed concrete pavers providing mechanical protection against garden implements . Christie’s walk garden, adelaide

14. A proprietary polyethylene mesh (rather than heavy gravel) was laid as a drainage layer. Geotextile was laid on the mesh followed by a thin layer of sand. Finally, 350mm of growing medium (lightweight soil) was blown up on to the roof through a kind of giant vacuum cleaner. Clay pavers have been used to deliniate between pathways and growing spaces. An irrigation system of microsprays keeps it watered with recycled water during summer, twice a week. There is a bottomless metal container, with lid, which holds worms that are fed once or twice a week with veggie scraps. A small pond with water plants has been added – to attract birds as well as allowing small children (under supervision) to dangle their feet.

15. Benefits Expand roof life 2x3 times Reduce air-conditioning cost Stormwater management Improve public relations Transform dead space into garden space Reduce city “heat island” effect Reduce smog and improve air quality Reduce noise Reduce energy demand Improves aesthetics

16. DISADVANTAGES Structural limitations Installation and maintenance costs are high. Susceptible to damage and leakage. The limited number of plants. An increase in weight load.

17. PLANTING http://googleweblight.com/i?u=http://www.bhg.com/gardening/design/styles/best-plants-and-trees-for-rooftop-gardens/&grqid=wYWlxNuF&hl=en-IN