4.4 Shading
- General guidelines for all climates
- Fixed shading
- Adjustable shading
- Climate specific responses
- Using plants for shading
- Shading and daylight
- Shading for a healthier environment
ADJUSTABLE SHADING
Adjustable shading allows the user to choose the desired level of shade. This is particularly useful in spring and autumn when heating & cooling needs are variable. Note: active systems require active users.
Climate Change
Climate change does not affect sun angles,
but the desirability of shade or solar gain
may change, this affecting the overall
design strategy.
Adjustable shading (mechanical or seasonal vegetation) will facilitate adaptation to changing climatic conditions.
Northern elevations
Adjustable shading appropriate for northern elevations includes adjustable awnings or horizontal louvre systems above glazing, and removable shadecloth over pergolas or sails. Shadecloth is a particularly flexible and low cost solution.
Eastern and western elevations
Adjustable shading is particularly useful for eastern and western elevations, as the low angle of the sun makes it difficult to get adequate protection from fixed shading. Adjustable shading gives greater control while enabling daylight levels and views to be manipulated. Appropriate adjustable systems include sliding screens, louvre screens, shutters, retractable awnings and adjustable external blinds.
North-east and north-west elevations
Adjustable shading is recommended for these elevations as they receive a combination of high and low angle sun throughout the day. Typical responses for northern and eastern or western elevations need to be integrated. Select systems which allow the user to exclude all sun in summer, choose full sun in winter, and manipulate sun levels at other times.
CLIMATE SPECIFIC RESPONSES
Hot humid climates and Hot dry climates with warm winters: Shade the building and outdoor living spaces throughout the year.
All other climates: Use appropriate passive solar design principles.
[See: Australia's Climate Zones; 4.1 Passive Design; 4.5 Passive Solar Heating; 4.6 Passive Cooling]
Hot humid climates
Shade all external openings and walls including those facing south.
Use covered outdoor living areas such as verandahs and deep balconies to shade and cool incoming air.
Use shaded skylights to compensate for any resultant loss of natural daylight.
Choose and position landscape to provide adequate shade without blocking access to cooling breezes.
Use planting instead of paving, to reduce ground temperature and the amount of reflected heat.
A 'fly roof' can be used to shade the entire building. It protects the core building from radiant heat and allows cooling breezes to flow beneath it.
Hot dry climates
Shade all external openings in regions where no winter heating is required.
Provide passive solar shading to north facing openings in regions where winter heating is required.
Avoid shading any portion of the glass in winter - use upward raked eaves to allow full winter solar access, or increase the distance between the window head and the underside of the eave.
Use adjustable shade screens or deep overhangs (or a combination of both) to the east and west. Deep covered balconies or verandahs shade and cool incoming air and provide pleasant outdoor living space.
Place a shaded courtyard next to the main living areas to act as a cool air well. Tall, narrow, generously planted courtyards are the most effective when positioned so that they are shaded by the house.
Use planting instead of paving, to reduce ground temperature and the amount of reflected heat.
Warm humid and warm/mild temperate climates
Provide passive solar shading to all north facing openings, using shade structures or correctly sized eaves
Use adjustable shade screens or deep overhangs to the east and west. Adjustable shade screens are the most effective at excluding low angle sun.
Cool temperate climates
Do not place deep covered balconies to the north as they will obstruct winter sun. Balconies to the east or west can also obstruct winter sun to a lesser extent
Avoid shading any portion of the north facing glass in winter- use upward raked eaves to allow full winter solar access, or increase the distance between the window head and the underside of the eave.
Use deciduous planting to the east and west. Avoid planting to the north which obstructs solar access.
USING PLANTS FOR SHADING
Match plant characteristics (such as foliage density, canopy height and spread) to shading requirements. Choose local native species with low water requirements wherever possible.
In addition to providing shade, plants can assist cooling by transpiration. Plants also enhance the visual environment and create pleasant filtered light.
[See: 2.4 Sustainable Landscapes]
Deciduous plants allow winter sun through and exclude summer sun.
Trees with high canopies are useful for shading roofs and large portions of the building structure.
Shrubs are appropriate for more localised shading of windows.
Wall vines and ground cover insulate against summer heat and reduce reflected radiation.
SHADING AND DAYLIGHT
Choose shading methods that allow adequate amounts of daylight into the building while preventing unwanted heat gain.
Select plants that allow filtered light into the building.
[See: 2.4 Sustainable Landscapes]
Design glazing to admit maximum light for minimum heat gain. Clear sections in verandah roofs can be useful.
[See: 4.10 Glazing]
Light coloured external surfaces or shading devices reflect more light into the building. Depending on the situation this can be beneficial, or it can create unwanted glare.
SHADING FOR A HEALTHIER ENVIRONMENT
Appropriate shading practices reduce the chance of exposure to harmful UV rays. Planting is a low cost, low energy provider of shade that improves air quality by filtering pollutants.
| ADDITIONAL READING |
|---|
| Energy Efficient Building Design Resource Book Brisbane Institute of TAFE Unit 5 Windows & Shading |
| Energy Efficient Housing Manual, Energy Victoria Plant selection guidelines for shading (vic) p106-111 Calculating the size of north facing shading devices (vic) p34-36 |
| BDP Environment Design Guide, RAIA Space Cooling GEN 18-19 p4 Landscape for Shade and Cooling DES 9 p3 The Shade Audit DES 32 Retrofitting residential buildings to reduce greenhouse gas emissions, DES 38 parts 2 & 4 |
| AMCORD, Commonwealth Department of Housing & Regional Development Site planning & building design, parts 5.4, 5.7, 5.10 |
| Warm House, Cool House, Hollo, N Shading of glazing p.24-27 |
| Geoscience Australia Website http://www.ga.gov.au/geodesy/astro/smpos.jsp |
Principal author:
Caitlin McGee