Effects of Climate on the Form and Elevation of Buildings in Iran
Nazanin Salimi


Climate divisions and architectural typology
According to the native architectural forms and structures in different areas of Iran, it seems that that the variable characteristics of different climates in Iran have affected on creation of the cities and also the architectural formation of these areas. Therefore, the exact distinction of climate districts in the country, and also acquiring the climate characteristics in different areas has very important role in suitable designing. We study native architecture characteristics according to the four climate areas of Iran due to the relationship between climate and architecture of each area and also the difference of climates that has created the changes, native architecture of different areas and finally determination of architecture typology of Iran.

       Native architecture characteristics in the areas with mild and humid climate
       Natural effective parameters on building
1-Sun
Due to the high rainfall in these areas, the roofs are made with high slope. The slope level with west-east direction gets lighter in summer in comparison with winter. Surfaces with the slope toward south get more sun radiation in winter. In autumn and spring, the south slope surfaces get 20% or more than the east and west slope surfaces. Surfaces with the slope towards north receive the less sun radiation during the year.

2-Wind
The way of blowing of the wind in an area is an important parameter for determining the building’s direction. In north humid areas of Caspian Sea beaches, sea and earth breezes are blowing. Their direction during the day is from the sea towards the beach and during the night, it is from the beach to the sea while the direction and the severe of the movement of these breezes are effected by pressure differences. In summer when the

Pressure in northern beaches of Iran is more than the pressure in central plateau , the air moves from the area with high pressure i.e. from sea towards beaches; for this reason Mangil area has hard northern winds during the whole summer. Natural ventilation, with no except, is used in all the buildings of this area. In general, all the buildings have expanded and open plans and all of them have long and narrow geometric plans. For the main use of the wind blowing to create natural ventilation, rooms are located in the buildings due to the blowing of the wind. In the areas with high blow of the wind, all parts of the building towards the wind are completely closed. Because of using the best of wind blowing and because of great water sources and availability of water, the buildings are located non-concentrated and with big distances.

3- Humidity and Rain Fall
       3-1- Rain fall
Because of high rainfall in these areas, the roofs are made with slope and mostly with high slopes effecting the form of the buildings to keep the rooms safe from the rain, the extended - balconies are made around the rooms. These spaces are used for working, resting and sometimes for storing agricultural products during the most times of the year.

       3-2- Humidity
In high humidity beaches and the borders near the sea, the buildings are made on the wooden pedestals to prevent the penetration of humidity inside the building but on the slopes of the mountains, with less humidity, houses are built on the stone, soil...

Different ways of the penetration of the humidity into the buildings
Humidity in the building is maybe as a result of some parameters as the penetration of rain into the wall and the roof, or into the internal surfaces from the seams of the windows, and great humidity because of the internal systems producing the humidity and penetration of water from walls and roof.

Choosing the material of the walls to prevent the penetration of humidity into the internal spaces
Materials such as brick, and usual concrete or light concrete and cement block are penetrable against water and steam and when these materials are exposed to rain, distills will appear in them. To prevent the penetration, it’s necessary to cover the outside surface of such walls with special and good quality layers. It applies to the cement block too. Empty walls with masonry materials consist of an external layer and an internal layer and surround a space between itself, if there is no connection between these two layers, The internal air of the wall cuts the stream of humidity, therefore it prevents the direct penetration and frequent penetration of rain from the external layer of wall to the internal layer.

Filling the empty spaces between two layers with the materials strong against the heat, which are water resistant, increases thermal strength of the wall and doesn't have a negative effect on the wall-strength against rainfalls. If the conductor layers are installed inside the wall to increase the thermal strength of the wall, all layers must be uniform and with no steam to prevent the humidity penetration inside the wall.

The best and useful wall that can meet all the problems of preventing the humidity inside the buildings is a two-layer wall consists of heavy, thick and internal layer, which is penetratable having thermal strength and an external non-penetratable cover. In the empty space between this two-layers, it must be possible to create ventilation and also evacuation of the water result from humidity. Therefore this high humidity only appears in the internal surface of external layer and doesn't hurt the main wall, or in other words the internal layers.