Stone Masonry Foundation

The place where stone is in abundance or in rocky or hilly terrains, the brick may not be viable solution for foundations. Therefore brick is replaced by stone and this system of foundation works out to be cheaper, however, it is equally strong and durable and can be constructed by local mesons. A typical stone footing consist of several course of stones, the lowest course usually 2-2.5times the breadth of the wall above. A bed of lean concrete of uniform thickness is first spread over the entire length of the wall. The depth of concrete bed in normally not less than 150mm and its projection on either side of lowest course varies from 10-15mm

Random Rubble Masonry in Mud Mortar Over Sand Bed

The foundation is dug only to the required width and depth of the required spread. A sand bed of about 50mm is place over which stones of irregular size and shapes are placed and then covered with a layer of mud mortar. The succeeding layers are fitted to fill the crevices till the plinth level is reached. I case of high plinth, the surface of the random rubble masonry wall may be pointed with a cement lime mortar. In case of short stretches of bad earth, brick arches may be used to span the stretch below the ground level to give the desire strength. Local blue quartzite boulders would yield a solid foundation of about 300Kg/cm2 allowable compressive strength.

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Random Rubble Stone Foundation in Mud Mortar		RANDOM RUBBLE STONE FOUNDATION IN CEMENT MORTAR (1:8)
System Components	Initial Cost Structure	System Components	Initial Cost Structure
	Local Economy component = 30 % Foundation in cement mortar 1:8 of 450 x 450mm over 600 x 600 footing in hard stone (granite) from quarry		Local Economy component = 30 % Foundation in cement mortar 1:8 of 450 x 450mm over 600 x 600 footing in hard stone (granite) from quarry
DESIGN EXAMPLE : Foundation for a single storey Building		DESIGN EXAMPLE : Foundation for a single storey Building
Maximum width required = 2 x width of the wall + 0. 3m (Assuming 23cm thick brick wall)= 2 x 0.23 + 0.3 m. = 0.76m. Minimum depth required = Assuming P > Safe permissible pressure on base) = 125 KN/sqm W (weight of soil) = 18 KN/sqm Angle of repose of the soil = 30 = 125/18x0.111= 0.77 m. Assuming bearing capacity of soil = 200 Km/sqm Width required = 125/200 = 0.625m Thus provide a foundation width = 76 cm and depth 77 cm		Maximum width required = 2 x width of the wall + 0. 3m (Assuming 23cm thick brick wall)= 2 x 0.23 + 0.3 m. = 0.76m. Minimum depth required = Assuming P Safe permissible pressure on base = 175 KN/sqm W (weight of soil) = 18 KN/sqm Angle of repose of the soil = 30 = 175/18x0.111 = 1 m. Assuming bearing capacity of soil= 200 Km/sqm Width required = 175/200 = 0.85m Thus provide a foundation width = 85 cm and depth 100 cm
Critical Factors	Tools Used	Critical Factors	Tools Used
1. Quality of soil 2. Width and stepping of foundation 3. Providing through stones 4. Protection from water 5. Inter-locking at corners	1. Trowels 2. Plumb bob 3. Thread 4. Pans 5. Shovel 6. Pick axes 7. Baskets	1. Workability and strength of stone 2. Width and stepping of foundation 3. Providing through stones 4. Grading of sand 5. Inter-locking at corners	1. Trowels 2. Plumb bob 3. Thread 4. Pans 5. Shovel 6. Pick axes 7. Baskets 8. 8. Hammer (Big & small)
DO'S	DON'T'S	DO'S	DON'T'S
1.Soil should have medium plasticity 2. Thorough stones should be provided 3. Natural bed of stone should be always Perpendicular to the loading	1. Sand and clay should be used for mortar 2. Rounded stone should not be used for Masonary 3. Masonry should not be allowed to dry out quickly 4. Bonding of the wall should not be filled with small stone pieces	1. Curing should be done for seven days 2. Thorough stones should be provided 3. Natural bed of stone should be always perpendicular to the loading. 4. Mortar should be used within 30 minutes of adding water to the mix	1. Find sand should not be used for masonry 2. Rounded stone should not be used for masonary 3. Masonry should not be allowed to dry out quickly Bonding of the wall should not be filled with small stone pieces

Stone Masonry Foundation

Random Rubble Masonry in Mud Mortar Over Sand Bed

Random Rubble Stone Foundation in Mud Mortar

RANDOM RUBBLE STONE FOUNDATION IN CEMENT MORTAR (1:8)