Constructing Home In A Hilly Terrain? Here Are Some Tips For You
Construction of a home on a hilly terrain can be a huge challenge when compared to the methodologies used in plains. A completely different topography, climatic conditions and geological challenges, the architects taking up projects in the hills have to take special measures to give the building the required structural strength. Cities such as Pune, Navi Mumbai etc where land conditions in suburban areas are similar to mountainous areas due to terrain features, tall buildings here are more prone to danger if proper care is not taken during the development process. Here few tips and checks to ensure that your property in such a terrain meets all security checks:
Consider the site selection
Site selection is one of the prime challenges while constructing in hilly areas. Some of the things that you need to keep in mind include whether or not the location is landslide vulnerable or located on a slope or on a sequence of rock structures or have existing subsurface water with existing streams. Each of these situations requires special care if constructing here. According to Prof BS Kotlia, Centre of Advanced Study in Geology, “Areas that receive extremely heavy, non-stop and concentrated rains (100 mm to 120 mm in one hour) called cloudburst or are situated in the basal part of a high hill where soil is loose, hard rocks are missing and have steep hills in surroundings should be avoided as these are more vulnerable to accidents.”
Investigate past site history
It is important to know whether the site has had any history regarding slope failures causing human injuries or casualties. Also, study the construction pattern in nearby areas to know how sustainability is practised there. A buyer should know that the buildings located on cut slopes suffer more damages as the slopes may have been excavated without any consideration for stability. “No residential buildings may be constructed on steeper slopes more than 25 degrees,” adds Kotlia.
Material to be used
Though wood has been one of the prime building materials in hilly areas, usage of reinforced concrete (RC) construction with moment frame type configurations has replaced this common practice. However, the poor quality of the material has plagued the challenges while constructing several storeys on hilly slopes or near rivers. Since it is mandatory to check the nature and behaviour of soil or rock at the cuttings or test pits or by boring in soils to check the wetness of the ground on which the construction is to be done, RCC strip foundations must be provided. There has to be adequate reinforcement along the wall to take care of loose and soft pockets below strip footing. Other green materials that can be used are steel framed construction, cement-wood-boards, sandwich panels, aerated concrete panels or gypsum plasterboards.
Precautions for homeowners
- Ensure that the technical investigation is done prior to earthworks. You can also request hazard zonation maps from the municipality.
- Suggest split levels designing on hill slopes to minimise erosion and earth slip.
- Natural vegetation acts as a resistor at the time of hazard, hence should be retained during site clearing.
- Cuts and fills should be reduced to minimum depths.
- Foundation should be very strong while the building over the ground level should be light.
- Prefer usage of light steel structures or a hybrid structure (RCC + steel). In such cases, installation of a tin roof and a light wood ceiling may be preferred.
- Check if the area has been already hit by cloudbursts or any related disasters.
- Owners should always look out for emerging new cracks, abnormal bulges in the ground and pathway pavements, soil moving away from slopes and building foundations, tilting of terraces, increase in cracks on solid floors.