Usual sizes of stones of 30 cm × 30 cm, 45 cm × 45 cm or 60 cm × 60 cm with a thickness of 2–4 cm are used. Generally square stone slabs of the above sizes are used but the slabs can be of rectangular or oblong in shape with square edges. Stone slabs are laid on concrete bedding.
Before laying the slab a base is prepared after excavating to the required depth and the earthen base is levelled, rammed and watered. A layer of lime concrete of thickness 10–45 cm is spread over which the concrete bed or sub-grade is laid.
After setting the stone floor with a slope of 1 in 40, the mortar joints are raked out to a depth of 2 cm and flush pointed with cement mortar of 1 : 3.
Following aspects are kept in mind while laying stone slabs, Fig. 23.1:
- To begin with two stone slabs from diagonally opposite corners are laid. A string is stretched touching these corner slabs so as to fix top level of the floor.
- Intermediate slabs are placed from both the sides taking care that the tops of stone slabs are touching the string which ensures the provision of proper grade.
- All stone slabs should be of uniform thickness, strength and well drained on edges for residential and public buildings.
- Width of joints between the slabs should not exceed 0.5 cm.
- Rough surface stone, may be used for godown, sheds, stores, etc.
Figure 23.1 Stone flooring
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