Roof Gardens

Roof Gardens

Actually roof garden is referred to any planned garden on the top of  roof of a building.
 History reveals that Humans have grown plants on top of building since ancient times.

ü  The ziggurats of ancient Mesopotamia (4th millennium 600 BC) had plantings of trees and shrubs on above ground terraces.

ü  In Roman times the Villa of the Mysteries in Pompeii, had an elevated terrace where plants were grown.

ü  A roof garden has also been discovered around an audience hall in Roman-Byzantine Caesarea.

ü  The medieval Egyptian city of Fustat had a number of high-rise buildings that Nasir Khusraw in the early 11th century described as rising up to 14 stories, with roof gardens on the top story complete with ox-drawn water wheels for irrigating them.

Roof garden VS Green garden

These two terms are often used interchangeably-some times making confusion.

Ø  Roof garden  means roof spaces  that provide recreation, with additional outdoor living space

Ø  Roof garden  may include planters, plants, dining , furniture, outdoor structures (pergolas and sheds) and irrigation &lighting systems.

Ø  While  green roof is not necessarily designed for to provide any recreational rather constructed to Improve  insulation or overall energy efficiency

Ø  Reducing the cooling and heating costs within a building.

Benefits of Roof gardening

Besides the decorative aspect, Roof gardening rendered following

additional benefits

•      Roof plantings may provide food- sometimes referred to as rooftop farming

•      Temperature control

•      Reduce energy consumption

•      Hydrological benefits,

•      Architectural enhancement

•      Habitats or corridors for wildlife, and

•      Recreational opportunities.

•      Increase access to private outdoor green space-at home or at work-within the urban environment

•      Promote individual, community, and cultural diversity

•      Improve air quality and reduce CO2 emissions

•      Delay storm water runoff

•      Insulate buildings

•      Increase the value of buildings for owners and tenants

•      Create job opportunities in the field of research, design, construction, Landscaping/gardening, health, and food production

Categories of Roof gardens

Three basic types of roof , and these three types relate to

ü  The amount of maintenance they require,

ü  The depth of soil and the types of plants the area will support.

The three types are:

1- Extensive living roofs

ü  They are easy to maintain and use on shallow soils

ü  They are lightweight and used on sheds, garages and small extensions.

ü  They adopted to harsh environments 

ü  They  are easy to maintain also lack visual appeal.

2- Semi-Extensive living roofs

ü  These roofs have deeper soils and support a greater number and wider variety of plants

ü  Their depth makes them heavy so require a strong structure to support them.

ü  They can combine the relatively low maintenance of Extensive roofs with a more aesthetic appearance.

3-  Intensive living roofs

ü   They are big and support full gardens

ü  They require large and strong structures

ü  They are unsuitable for domestic buildings

Roofs suitability:

Ø  Flat roofs are best for roof gardens - although other roof types such as domed roof can be green.

Structures typically used for domestic roof gardens

Garage

i- Garages with flat asphalt roofs can support a lightweight living roof such as a sedum blanket

Ii- Garages with concrete deck has been used, a deeper substrate-based, hat can be used to grow wildflowers.

Sheds

Sheds are often quite lightweight structures so it is often inadvisable

o build any greenery on them .

If still needs then

ü  checking for suitable support first,

Extensions

It should be possible to build a roof garden on an extension but the

type largely depends on the supporting structure underneath.

How to develop Roof garden?

To build a garden for flowers requires several layers to be constructed:

1- Waterproof layer

ü  It is a base layer, added to the existing surface

ü  It will give greater security and peace of mind even if the roof is already waterproof.

2- Roof membrane

ü  Waterproofing layers, such as asphalt and bitumen, are very susceptible to damage from plant roots and any root penetration may lead to leaks.

A pond liner or butyl lining or 300 micron damp-proof polythene should be laid over the waterproof layer (wherever possible, in one continuous sheet. Otherwise, the sheets should overlap by at least 20cm).

3- Filter Sheet

ü  This sheet allows moisture to drain off of the roof whilst ensuring fine materials don't escape.

4- Moisture Blanket

ü  For extensive living roofs, this blanket will ensure that the growing medium contains enough moisture to support life.

ü  Commercial ones can be bought but it is possible to use cardboard or old blankets to achieve the same effect.

5-Drainage layer

ü  Like the moisture blanket, this helps to retain moisture while allowing excess water to drain away.

ü  Commercial systems store water and are made of plastic or geo-textile materials.

6- Soils and Substrates

ü  The top layer. The growing medium should be lightweight and free draining yet of a material that retains moisture.

ü  Many people use aggregates mixed with light sub-soils such as crushed porous brick and limestone chippings.

7- Seeds and Plants

ü  Sow seeds on the substrate, or

ü  put in plug plants (small plants in individual cells) and watch them grow!

Green Roof System

Roof garden Plants

There are various plants you can grow in your roof garden, each with their own characteristics.

Mosses and Lichens

ü  The lightest living roofs – and the simplest to create

Sedum Roofs

ü  If a green carpet of sedums is the goal then it will regular weeding, however a less intensive regime will result in more mixed vegetation, as grasses and other plants invade.

Wildflower Roofs

ü  For extensive living roof types it should be possible to develop a wildflower meadow with little or no intervention

ü  Low fertility substrates will give rise to short vegetation that will not need cutting back each year.