One of the main objectives of architectural design is to ensure indoor comfort in buildings through natural means. This objective can be ensured by several design strategies and one of the major ones is to optimise the building orientation and form. Continue reading to understand what building orientation means, why it’s important and how to optimise the orientation of a building to get the best design.
What is Building Orientation?
Building orientation refers to the directions along which a building is positioned or faces. Although a building generally has surfaces that face four directions, its orientation is said to be along the directions that its largest surfaces face. The orientation of a building is an important factor that guides architectural design and is based on several factors like wind directions, solar pathways and climatic conditions. The best orientation is often derived by thorough site analysis processes.
Why is the Orientation of the Building Important?
A building that has optimised orientation offers several benefits, such as:
- Thermal Comfort: Optimised building orientations ensure that users are thermally comfortable inside without relying on mechanical ventilation systems. This leads to enhanced physical and mental wellbeing.
- Energy Efficiency: With optimum natural light and ventilation, such buildings have a lower reliance on HVAC systems, resulting in reduced utility bills and more energy-efficient spaces.
- Building Longevity: Issues like water seepage, energy leakage and mould development are avoided in buildings with adequate cross ventilation and natural light, thus enhancing the building’s durability.
- Certifications: Several green building certification agencies consider orientation to be a major factor for awarding points on building sustainability. Obtaining these certifications enhances property value and social prestige.
Design Considerations for Optimising Building Orientation
Environmental and Physical Considerations for Building Orientation
Solar Radiation
The amount, duration and intensity of sunlight received in every direction is different. In most parts of India, the South and West directions face the maximum amount of solar heat, while the North direction receives the most favourable quality of sunlight. Therefore, building orientations can be designed on the basis of the prevailing climatic conditions. For example, buildings in cold climates can maximise the area of South and West facing surfaces to get adequate heat into the building.
Wind Direction
The wind direction, speed and duration must all be considered for optimising building orientations. In India, the major wind directions are from Southwest to Northeast and vice-versa. Apart from these, local winds caused due to pressure differences, height variations, vegetation, neighbouring structures and land and sea breezes must also be considered for building design. Buildings oriented perpendicular to wind directions experience the highest wind speeds, while a 45 degree orientation can reduce the wind speed by half.
Climatic Conditions
India has six major climate zones- warm & humid, hot & dry, composite, cold & cloudy, cold & sunny and moderate climate. Climate responsive architecture principles must be analysed to understand the different building orientation requirements in each of these climates. For example, the goals of house orientations and forms in each of the climate zones are:
- Hot and dry climate: to reduce solar radiation and wind speeds. Good architecture for hot and dry climates can be achieved by orienting the building against the major wind directions and avoiding large building surfaces towards the West.
- Warm and humid climate: to increase cross ventilation and reduce solar heat gain. Passive design in warm and humid climates includes orienting the building towards the major wind directions and avoiding/ reducing the areas of South and West facing surfaces.
- Composite climate: to reduce the internal temperature difference between the night and day (diurnal temperature range). Here, compact built forms can reduce the heat gain and loss, ensuring enhanced internal temperatures.
- Cold and sunny climate: to introduce humidity and winds while reducing the diurnal temperature range. Compact built forms oriented towards water bodies and/or major wind directions are helpful here.
- Cold and cloudy climate: to increase solar heat gain. Building orientations towards the South and West can help maintain warm indoor conditions in this climate.
Site Conditions
Before locating and deciding the orientation of a building, the following site factors must be considered:
- Accessibility: Access to the site through both vehicular and pedestrian pathways has an impact on building orientation. For example, on small sites with a single abutting road, commercial buildings like shopping centres have to be oriented towards the road to ensure maximum visibility and ease of consumer accessibility.
- Soil strength: Several times, due to weak or varying soil strength on sites, certain types of foundations such as raft or mat foundations with specific footing locations are recommended. These make it necessary for buildings to be designed with a particular form and orientation.
- Site levels: Steep site contours can dictate the building orientation. For example, in a mountainous region, it may be possible to build only in flattened areas with narrow elongated shapes and this requires the building to have the same shape and orientation.
Internal Building Layout
It is advisable to place the main residential spaces like living rooms and kitchens towards the sides which do not gain excess heat in the morning. On the other hand, bedrooms can be placed here as the same heat gets transferred inside at night, keeping the room warm during cold nights. Therefore, while designing architectural plans that ensure indoor comfort, certain building orientations and forms are naturally derived.
Shading Devices and Materials Used
When adequate shading devices—such as roof overhangs, louvres and chajjas—passive house design can be achieved even without orienting the building as per the wind and solar directions. The materials used also have a large impact on this. For example, large glazed surfaces can gain adequate solar heat even when they are facing the North direction.
Sociological Considerations for Building Orientation
Neighbouring Structures
Orientation in building planning must be optimised to obtain the best views from openings, especially in large scenic plots. Large surfaces that are very close to other large neighbouring structures must be avoided to ensure adequate cross-ventilation and daylight in both buildings.
Vastu
The principles of Vastu Shastra are commonly followed in India. These principles guide building orientation and directions. For example, the main entrance to a building must preferably be in the Northeast, East or North, meaning that the building must be oriented to enhance entrances in these directions. Vastu also specifies directions for the best house orientation in order to promote harmony and prosperity. For instance, the North orientation encourages stability, while the East welcomes new beginnings.
Building Byelaws
Several factors of local regulations and building byelaws dictate building orientation, such as:
- FAR: Floor Area Ratio (FAR) refers to the ratio of built-up area to the plot area. FAR affects how high the building can be and the amount of setbacks that must be left.
- Road Widths: The number of floors that can be legally built on a site depend on the width of the abutting road.
- Environmental Restrictions: Sensitive zones—such as areas close to reserve forests, lakes and wetlands—have restrictions on buildable areas. Buffer zones (open spaces where construction cannot be done) must be left near such areas.
After complying with these regulations, only specific portions of the complete plot may be legally buildable. This means that the orientation of the building must also be aligned with the buildable portion.
Getting the Best Building Orientation in Home Design
To optimise building orientation and form, a thorough analysis of all physical, environmental and sociological factors is necessary. It is also important to analyse the individual customer and project needs and budgets. Brick & Bolt, an end-to-end construction services provider in India, provides customised floor plans for every project after analysing all these factors. Its team of top architects and designers collaborates with construction professionals to ensure that these designs are executed precisely and at affordable rates. To ensure the best building orientation in your residential or commercial construction projects, get in touch with Brick & Bolt today!
Apoorva H P Achar