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Where stones are available in abundance and nearby, they can be used in building construction to economic advantage. Stones are usually cheaper than bricks in places where they are available. The main advantages with stone are that cutting of holes for fixation of plumbing, water supply and electrical services, inserting of still clamps etc are difficult and expensive. Whatever is the type of stone masonry, certain general procedure is to be followed in all cases. Stone blocks shall be laid on their natural bed. Where stones of irregular shapes are used, they shall be laid with their broadest face downwards.
All stone blocks shall be sufficiently cleaned of all weathering surfaces and shall be wetted by sprinkling water over them before use. Stone masonry can be laid in cement mortar, lime mortar, or mud mortar. They can be laid dry if they are well dressed. If lime mortar is used, kankar lime is to be preferred. Stones shall be laid so as to bear evenly and fairly on the mortar bed prepared for them. The joints at the sides are to be carefully filled in solid.
Particles of mortar which get splashed over the exposed faces of the masonry shall be cleaned off before they are set. Exposed joints shall be raked out to a depth of 12 mm while the mortar is still green, for pointing or plastering to be subsequently done.
Stone masonry shall be laid as level as possible along the whole length of the work. The depth of courses should as far as possible be equal. Each course is to be properly bonded with the course immediately below or above it. In walls ‘bond’ or ‘through’ stones of the same length as the thickness of the wall shall be provided at regular intervals. At corners and junctions of walls, headers from one direction should go well into the body of the masonry in the other direction so as to unite the whole work thoroughly. Work in both directions must be executed simultaneously. Steel clamps for fixing door or window frames shall be embedded in cement concrete (1:3:6) as the work progresses. Holes for drainage or for ventilation, ducts and recesses for pipes and cables, and wooden plugs to take electric or other fittings needing screwing or nailing shall also be provided as the work progresses so as to avoid any cutting at a later stage. The work should be cured for at least 15 days after laying of masonry by sprinkling water and by keeping the top of wall ponded.
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