Figure 3.1.11 Roof garden of Hysan Place
(Source: Hysan Development Company Limited)
Exterior Landscape
Overview for Office Building
Design of the outdoor green space should be integrated with the building design of the office building and the functional
needs of the office building and the office spaces. One of the key factors to be considered is the plant size and suitability
of the plant species (“Right species for right place” principle) for long term sustainable growth.
The following greenery methods are commonly adopted:
• Ground greenery
• Green roof/sky garden
• Vertical green wall
Provision of an outdoor green space brings benefits to both the building as well as to the surrounding environment.
Outdoor greenery helps reduce the heat island effect and create a more pleasant environment around the office building.
Lighting design reference: “Guidelines on industry best practices for External Lighting Installations” released in June 2015
by Environmental Bureau, Environmental Protection Department and Electrical and Mechanical Services Department
BEAM Plus NB V1.2 SA P1
Appropriate planting shall be provided on site equivalent to at least 20% of the site area.
Benefits of Green Office Building
• Protect against heat build-up and
control ambient temperatures at a
macro level
• Create a more habitable space
for people and animals thereby
promoting biodiversity
• Reduce runoff, provide natural rain
water filtration, and alleviate storm
drainage pressure
• Cool the air in summer by a process
called evapotranspiration, reducing
the need to cool the building
• Green roofs can last two or even
three times longer than conventional
roofs hence it reduces the material
waste from re-roofing and induces
lower costs over time
• Green roofs can reduce building heat
gain, and also mitigate urban heat
island effect
• Green roofs also provide insulation
and acoustic dampening
• Tree planting at pedestrian level is
very effective in moderating urban
climate and in promoting human
thermal comfort as tree canopy
not only cools the air space at
pedestrian level, but also provides
shading and thus lowers direct
radiation from the sun
z
Consider the ease of mainten-
ance, tolerance to pollution
and vandalism and public safety
when selecting plant species
z
Location to enhance natural
ventilation and reduce glare and
heat gain (create shading)
z
P a r t i c i p a t o r y f a r m i n g
z
Enhance biodiversity by in-
creasing the diversity of plants
and the structure of vegetation
provided, as well as establishing
connected habitats for wildlife
z
Vertical green wall can be
adopted to lower building
heat transmission and prevent
weathering of building façade
z
Native species should be widely
used as a priority
z
Establishment of connected
green corridors and lines of trees
to provide more shaded routes
for pedestrians
z
At grade tree-planting can be in-
troduced at suitable locations to
provide shade for the buildings
and pedestrians
z
Green roof to provide thermal
insulation
• Vertical greening not only reduces
heat transmission into the building,
especially if installed on the east and
west façades but also protects the
façade from weathering
• Outdoor greenery can provide a
quality view for another building,
creating a pleasant view for staff
working in an office building
• Landscape is believed to affect
human beings in many ways,
including aesthetic appreciation,
health and well-being
• Experience of nature can improve
working experience, mood and
happiness
Green Strategies for Office Building
Read more at:
an Trees of Hong Kong. Accessed December 13, 2016.
DESIGN STAGE
3.1.3 Exterior Landscape
Green Roof
Hong Kong has used less than 25% of land for development. 66% of land in Hong Kong carries
vegetation, ranking 3
rd
in major cities in the world for average green space per person
1
. However, as
the green area is mainly located in suburban areas, and there is only limited access to greenery in
urban areas, there is a need to explore greening opportunities beyond ground level in urban areas.
Green roof has been shown to significantly reduce surface temperatures of roof. It is also a communal
space for building occupants which enhances well-being of tenants. Green roof can be classified into
extensive green roof and intensive green roof.
Extensive green roof:
• Shallow soil bases
• Low maintenance
• Do not need built-in maintenance systems
• Mostly not accessible for public use
Intensive green roof:
• Accessible for public use
• Known as roof garden
• Deeper soil base
• Include trees, palms, shrubs and turfing
• Designed with walkway, water features, seats and irrigation system
• Require regular maintenance
Vertical Greenery
There are two main ways to install a vertical greenery system:
Support System:
• Grown directly from ground adjacent to the façade
• Plants climb on specially designed support structures
• Lower initial investment cost
• Time is needed for desirable coverage
• Easier maintenance
Carrier System (Living Wall System):
• Consist of pre-vegetated panels that are fixed vertically to
a wall structure
• Support a great diversity and density of plants
• Irrigation system needs to be built into the green wall
• Higher maintenance cost
DESIGN STAGE
3.1.3 Exterior Landscape
Read more at:
1. Ng,
2016:
Office
BUILDING
Office
BUILDING
Ground Greenery
Greenery absorbs heat and cools the area through evapotranspiration. It is an important factor in creating a
sustainable environment. Below are some common ways to incorporate greenery into the development:
• Identify trees that can be protected and conserved. Leave them intact or remove and transplant back
• Provide as many trees as possible within the development since trees provide the most protection against
solar exposure when compared with other plants
• Densely planted shrubs, palms and small trees can act as an alternative to fence, boundary walls, etc
• Open grid paving allows surface rainwater runoff to filter into the ground, and reduces heat build-up in the
hard surface
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