Joints In Stone Masonry

Basics in Building Construction 4(2+2)

Lesson 09 : Stone Masonry

Joints In Stone Masonry

The common types of joints provided in stone masonry, to secure the stones firmly with each others are:

  1. Butt Joint or Square Jointh
    This is the most commonly used joint in stone masonry. The dressed edges of two adjacent stones are placed side by side.






  2. Rebated or Lapped Jointj
    This type of joint is provided in arches, gables, copings etc., to prevent the possible movement of the stones. The length of the rebates or lap depends upon the nature of the work, but it should not be less than 70mm.






  3. Tongue and Grooved Joint or Joggle Joint
    This type of joint is provided to prevent sliding along the side joints. Thea joint is made by providing projection or tongue in one stone and a corresponding groove or sinking on the adjacent stone.




  4. Tabled or Bed Joint
    This joint is used to prevent lateral movement of stones such as in sea walls where thze lateral pressure is heavy. The joint is made by forming a joggle in the bed of the stone. The height of the projection is kept about 30 to 40 mm, while the width is kept equal to above ? the breadth of the stone.




  5. Cramped Joint
    The joint uses metal cramp instead of dowels. Holes made in the adjacent stones should be of dovetail shape. The cramps are usually of non-coqrrosive metals such as gunmetal, copper etc with their ends turned down to a depth of 4 to 5 cm. The length, width and thickness of cramps vary from 20 to 30cm, 2 to 4 cm and 5 mm to 10 mm respectively. Wrought iron cramps may also be used but they must be either galvanized or dipped in oil while hot, to prevent their corrosion. After placing the cramps in position, the joint is grouted and covered with cement, lead or asphalt. Cramps prevent the tendency of the joints to open out due to slippage of the stones.




  6. Plugged Joint
    This is an alternative to cramped joints. It consists of making plug holes of dovetail shapme in the sides of adjacent stones. After placing the adjacent stones, a common space for plug is formed which is filled with molten lead. Sometimes, rich cement grout is used in the place of molten lead.








  7. Dowelled Joint
    This is a simple type of joint used to ensure stability of the adjacent stones againnst displacement or sliding. The joint is formed by cutting rectangular holes in each stone and inserting dowels of hard stone, gun metal, brass, or copper. These dowels are set in cement mortar.








  8. Rusticated Joint
    This joint is used in those stones whose edges are sunk below the general level, such ams for plinth, quoin, outer walls of lower storeys etc. Such a joint gives massive appearance to the structure.Various forms of rusticated joints are shown in figure 8.








  9. Saddled or Water Joint
    This type ofjoint is used in cornices and such others weathered surfaces, to divert the wmatermoving on the weathered surface away from the joint. The saddle is beveled backwards from the front edge as shown below.
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Last modified: Friday, 2 March 2012, 8:39 AM