What Is Pointing?
Pointing is the term given to the “finish” that sits between the bricks or stone used to build your home. Depending on the age of the building, the mortar used to deposit the stone or brick will be made of lime or, more recently, cement.
Pointing incorrectly causes irreparable damage to older buildings. It is essential to understand what mortar joints really do for the fabric of the home. The function of mortar on the wall is to act as a foundation between stones and varies from fine joints in the stonework to larger joints in rubble masonry walls.
The joints are effectively reduced in size by inserting small stones and ‘cut’ pieces of stone. While acting as a bed, the mortar must also perform other functions:
It must prevent water from penetrating through the joints due to its physical presence almost like a masonry ‘sponge’ but it must allow the wall to breathe and drain, porosity being a key factor when choosing a mortar to refer to.
It must be flexible to allow movement/settlement of the structure due to thermal responses and settlement within the structure. Many former large buildings are not designed with today’s modern expansion/contraction joints.
The strength of the mortar should always be less than that of the surrounding stones and should be considered as a sacrificial element of the wall and seen as a maintenance item that needs to be replaced, possibly every century.
The condition of the stone walls cannot be seen in isolation, and replacing any walls will not cure water ingress problems caused by other construction failures, such as gutters, roofs, and lead. They must be in good condition to maintain the useful life of the wall elements.
The walls need to breathe – and, if the indicator does not allow it, the wall will quickly deteriorate. Mortar joints are the lungs of a wall – they allow water inside the structure to enter and exit freely. If the water tries to come out through stone or brick, it will slowly disintegrate. Block the mortar joints, and the wall will be destroyed.
The mortar must be softer than the material with which the wall is constructed. The indication must be subservient to the material with which the wall is constructed and visually assume a secondary function.
Types of Pointing In Brick Construction
Pointing is the finishing of mortar joints in the construction of bricks. Aiming is the implementation of joints at a depth of 10 mm to 20 mm and fills it with better quality mortar in the desired shape.
It is made for cement mortar and lime mortar joints. Exposed joints are considered the weakest and most vulnerable points from which rainwater or moisture can enter.
Mortar for Pointing Works
- 1: 2 lime mortar (1 fat lime: 2 sand)
- 1: 3 cement mortar (1 cement: 3 sand)
Surface Preparation for Aiming
All masonry joints are joined to a depth of 20 mm, while the mortar is still soft. The joints and surfaces are cleaned and then completely wet.
After preparing the surface, as mentioned above, the mortar is carefully placed on the joints using a small spatula. The mortar placed must have the desired shape.
Whenever the fresh mortar is placed on the joints, it must be pressed hard to obtain a strong connection with the old internal mortar.
Care must be taken when using first-class ashlar or masonry. Otherwise, the mortar does not cover the edges of the face. The pointed surface is kept wet for at least a week or plowed after application.
Types of Pointing:
Different types of pointing are as follows.
1. Keyed Pointing
In this type of pointing, the mortar is pressed on the joints joined and finished with the face of the wall. While the pressed mortar is still green, a groove is formed, passing the folded end of a small steel bar (6 mm in diameter) straight along the centerline of the joints. Vertical joints are also finished in the same way.
2. Cut Pointing
In this type of pointing, the mortar is pressed first in joints. While the mortar is still green, the top of the horizontal joints is pressed from 3 to 6 mm with the pointing tool. Thus, the joint is finished by tilting from the top of the joint to the bottom.
3. Flush Pointing
In this type, the mortar is pressed hard on the joined joints and ends flush with the edge of the masonry units. The edges are well trimmed with a spatula and a straight edge. It doesn’t look good. However, aiming the flush is more durable because it resists the provision of space for dust, water, etc. for this reason, this method is widely used.
4. Recessed Point
In this case, the mortar is pressing 5 mm or more at the edges. During the placement of the mortar, the face of the sharpener is held vertically, using a suitable tool. This guy looks really good.
5. Beaded Pointing
It is formed by steel or ironed with a concave edge. It looks good but will damage easily when compared to other types.
6. Tuck Pointing
In this case, the mortar is pressed first at the anchored joint and finished with the face. While the pressed mortar is green, the channel or narrow channel is cut in the center of the channel, which is 5 mm wide and 3 mm deep.
This groove is then filled with white cement mass, projected beyond the face of the joint by 3 mm. If the projection is made in the mortar, it is called a pointing bastard or half a bend point.
7. V- Pointing
This is formed by forming a V-groove in the levelled finishing face. Weathered Pointing. This is done by making a V-shaped projection.