JOINTS IN STONE MASONRY

JOINTS IN STONE MASONRY

Introduction:

    1.      In masonry, joints are the spaces between stones that are filled with mortar or grout.

    2.      Joints can be made in a series of different fashions.

    3.      In stone masonry the joints are not of uniform thickness, shape, size.

Types of joints:

   1.      Butt joint

   2.      Reabated joint or Lapped joint

   3.      Table joint or Bed joint

   4.      Cramped joint

   5.      Plug joint

   6.      Dowel joint

   7.      Rusticated joint

   8.      Joggle joint

1. Butt joint:

    In this type of joint, the dressed edges of two stones are placed side by side.

2. Reabated joint:

    This type of joint is provided in arches, gables, copings, etc. where the stones are laid on slopes to prevent the movement of one stone over the other by sliding.

3. Table joint:

    1.      This type of joint is provided in sea wall, etc. to prevent the lateral movement of stones.

    2.      The joint is formed by making a joggle in the bed of stone.

    3.      The height of projection is kept 30 to 40 mm, and the width is kept equal to 1/3rd the width of the stone.

4. Cramped joint:

    1.      In this type of joints, the metal cramps are used to prevent the tendency of the joint to be pulled apart.

    2.      The dovetail shape holes are made in the both stones to be joined.

    3.      The cramps are usually made of non-corrosive metals, such as gunmetal, copper, etc.

    4.      After placing the cramp in position, the joint is grouted and covered with cement, lead or asphalt.

5. Plug joint:

   1.      The plug joint is an alternatively of cramp joint.

   2.      It consists of plug holes of dovetail shape in plan and cut below the top surface of stones.

   3.      The stones are joined by filling the holes with cement or lead.

6. Dowel joint:

   1.      This type of joint is used to ensure the stability of the adjacent stones against displacement or sliding.

   2.      The joint is formed by cutting the rectangular holes in both the stones and interesting the dowels made of slate, gun metal, copper or brass.

   3.      The dowels are set in cement mortar.

7. Rusticated joint:

        These types of joints are generally used in plinths or masonry in lower stories of buildings to give the structure splendid appearance.

8. Joggle joint:

The joggle-joint is made of metal or slate, which is placed between the groove provided in two adjacent stones; to prevent sliding along the side joints.