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Masonry work indicates the construction of structures using building blocks like stones, bricks, concrete, etc. The process involves significant physical, mental, and temporal demands. High task demands increase the likelihood of errors, with implications for rework, safety, and productivity. To ensure the durability of masonry work, it is important to better understand the task demands and manage them effectively.
Natural stone may vary greatly in its characteristics even when taken from different parts of the same quarry. Similarly, bricks are a man-made product and are subject to the unpredictable variations during the manufacturing process.
Mortar too is a vital constituent of masonry construction and it may vary in strength and durability. Thus, the material selection and construction process of masonry work becomes crucial for ensuring the durability of the structure.
This article describes the practices for field supervisors to observe when monitoring stone and brick masonry work. The advantages and disadvantages of brick and stone masonry work have also been discussed.
Contents:
1. Stone Masonry
Stone masonry construction is carried out using stones and mortar. But presently, stone masonry is not very popular because of the high cost of transportation, costly dressing work, and the need of experienced labor. Further, stone-masonry walls occupy more space compared to brick-masonry walls.
1.1 Supervision of Stone Masonry Building
The following points should be remembered while monitoring stone masonry work:
- Resilient and durable stones, devoid of flaws like cracks, cavities veins, etc. should be used.
- Dressing of the stones should be according to the requirement.
- Stones should be appropriately moistened before their use so that the absorption of water by the stones could be prevented.
- The direction of laying of stones should follow their natural bed.
- Facing and backing faces should be laid neatly. Moreover, the facing and backing faces should meet the requirement of wooden template.
- Stone chips and mortar should be used to fill the heart of masonry.
- Thick mortar joints should be prevented.
- Plumb-bob should be used frequently to check the verticality of the wall.
- Mortars with a proper percentage of sand and cement should be used.
- Most importantly, continuous vertical joints should be prevented.
- Through-stones should be used within 1.5 m of vertical distance.
- The height of masonry should not be uneven. Therefore, proper planning should be done before laying the masonry.
- Big flat stones should be used under the beams, trusses, and sills.
- Before continuing work, the masonry constructed on the previous day should be clean and devoid of loose particles.
- Curing should be done continuously at least for two to three weeks to attain strong masonry.
2. Brick Masonry
Brick masonry is constructed with bricks and different types of mortars. Mortar is used as a binding material. Lime and cement mortar are generally used for the construction of a permanent structure, whereas mud mortar is used for the construction of a temporary structure.
2.1 Supervision of Brick Masonry Building
In the construction of brick masonry, the following points should be observed:
- Use bricks of good quality with uniform color, well-burnt, with specific sizes and shapes.
- Bricks should not absorb water from the mortar. Therefore, prior to utilizing the bricks in masonry work, they should be put in water for at least two hours.
- The frog should always point upwards while laying the bricks in masonry work.
- Construction of a brick wall should begin from the end or corner of the structure.
- Plumb-bob should be used frequently to check the verticality of the wall.
- Mortar utilized must be in accordance with the specifications.
- At the end of the work, brick masonry should have toothed end.
- Brickbats should not be used extensively.
- Walls of brick masonry should be raised evenly. In a single day, no wall should be raised by more than 1.5 m.
- The face joints should be raised to a depth of 12 to 20 mm to get appropriate pointing or plastering when the mortar is green. If plastering or pointing is not required, face joints should be struck flush and finished neatly.
- Holdfasts for windows and doors should be embedded in brick masonry with cement mortar or concrete during the time of wall construction.
- Curing should be done for at least two weeks for brick masonry work.
- For performing brickwork at a greater height, single scaffolding should be used.
3. Benefits and Drawbacks of Brick Masonry
Benefits and drawbacks of brick masonry over stone masonry are discussed below:
3.1 Benefits
- Given that the sizes and shapes of bricks are consistent, it does not require experienced labor for construction.
- Bricks are light in weight, thus, working with them is easy.
- The easy availability of bricks along with their lightweight properties significantly decreases the transportation cost. Whereas stones are heavy and are to be brought from quarries, which are generally found at limited locations, making their transportation comparatively expensive.
- It is possible to utilize all kinds of mortar in brick masonry.
- Thinner walls can be built with bricks. However, it is not possible with stones.
- It is easy to form openings for windows and doors in brick masonry work. Therefore, the construction process becomes easy.
- Dead load of brick masonry is comparatively less than stone masonry.
- In brick masonry, mortar joints are thin, thus, reducing the construction expenses.
- Brick masonry has better fire and weather resistance than stone masonry.
3.2 Drawbacks
- Strength of brick masonry is less than stone masonry.
- Durability of brick masonry work is less.
- Comparatively, brick masonry work requires plastering, and plastered surface area requires color cleaning. Whereas stone masonry work does not require plastering and painting. For this reason, the maintenance expenses are more in brick masonry.
- Brick masonry absorbs water and therefore, there is a possibility of moisture penetration into the structure. There is no such issue in stone masonry.
- Generally, in stone masonry, architects can have more freedom to design as compared to brick masonry.
- Monumental buildings are constructed in stone masonry as it provides aesthetic appearance.
FAQs
Masonry work indicates the construction of structures using building blocks like stones, bricks, concrete, etc.
In most of the brick masonry structures, cracks appear due to the following reasons:
1. Combining the brick work with other materials. Thus, such approach develops more deflections and strains.
2. Significantly, the effect of deflection and shrinkage of the concrete slabs resting on walls causes cracks.
3. Development of internal forces due to moisture absorption and temperature variations can cause cracks in brick walls.
The most important measures to prevent cracking in masonry walls are given below:
1. The foundation supporting masonry walls should be designed with sufficient stiffness.
2. The provision of horizontal and vertical expansion joints should be provided in the walls. It will help in reducing the occurrence of cracks.
3. Concrete with low shrinkage characteristics should be used to prevent shrinkage cracks.
4. It is preferable to have short spans for the floor slabs to reduce deflection effects on walls.
Read More
Stone Masonry Construction – Materials and Classification