M.E. Structural Engineer
Since the idea of home came to the human mind, walls and roof have been its basic components and the walls are made with masonry. Masonry is one of the oldest methods of construction to civilization. It plays a crucial role in construction. Masonry is in the trade since ancient time. Especially, brick masonry is a most used as clay for bricks is abundantly available all around the world except dessert area.
Bricks are the most popular units for the construction of masonry walls in the building. With the advancement of time, the art or technique of brick masonry has also become advanced. Brick masonry is produced by laying the bricks in layers which are constructed by putting the bricks in a flat pattern and bonding them with mortar.
Brick masonry is classified as first class or second class according to the type of bricks used (whether first class or second class) and according to the method of laying. The strength of masonry work, however, depends very much upon the type of material used in masonry, nature of workmanship and supervision. Bad workmanship assisted by lack of supervision may lead to unsound construction in spite of the materials used being of the best possible type. The general guidelines which should be followed for a sound brick masonry work are given below.
Quality of Bricks Used in Brick Masonry Wall
- The bricks used in a brick masonry wall should be sound, hard and well burnt with uniform size, shape and colour.
- Bricks should have no cracks or flaws and a fractured surface should be free from holes, grit or lumps of lime etc.
- The surface of the bricks should be such that no mark should be made when scratched by the finger nail.
- The bricks when struck together should produce metallic ringing sound and they should not break when dropped from a height of 90 to 120 cm on the ground.
- The bricks should not as a rule absorb water more than 20% of their weight when dry, when immersed in water for twenty-four hours.
- The bricks should be thoroughly soaked in clear water before use for suitable period so that the water just penetrates the full depth of bricks. This not only help in removing the dirt, dust and other soluble salts (which cause efflorescence) from the bricks, but also reduce their tendency to absorb of water from wet mortar. In case, however, masonry is to be carried out in mud or fat lime mortar, the bricks should not be soaked in water before use.
Scaffolding for Brick Masonry Wall
- In order to carry out the brick work at higher level, double scaffolding should be used. Single scaffolding results in holes being left masonry which is not recommended as it can cause subsequent leakages.
Also Read: All the Basic Guide for Scaffolding!
Quality of Water Used in Brick Masonry Wall
- Water used in brickwork for curing and mortar should be potable one and off course free from salt.
- Water which is used to make brick should also free from salt.
- Potable water should be used for mortar, curing and for the manufacture of bricks. If not done, efflorescence is going to appear.
Quality of Clay for Brick
- Clay which is used to manufacture brick should be also free from salts.
Laying of Bricks in Brick Masonry Wall
- The bricks should be laid on full bed of mortar.
- The bricks should be slightly pressed into the bed mortar while laying so as to ensure proper adhesion.
- All the courses should be laid truly horizontal and all the vertical joints should be truly vertical.
- Unless brick-on-edge is specified, the bricks must be laid on their proper beds with their frogs pointing upwards.
- The courses of bricks at the plinth, window sill, floor/roof level and the top of parapet wall should invariably be laid with brick on edge.
Also Read: Various Shapes of Brick used in Construction
- As a general practice, quoin brick should be headers and stretchers laid in alternate courses and the bond is developed by placing a quoin closer next to the queen header.
- In the brick work the brick should be laid with adequate gap between them on their bed with the frogs pointing upwards so that mortar gets mechanical bond / key between the two layers of bricks.
Also Read: Types of Masonry used in Construction
Joints in Brick Masonry Wall
- All the joints should be properly flushed and filled with mortar so that no cavity is left in between.
- In case of walls with two bricks or more in thickness, the joints should be grouted at every course in addition to bedding and flushing with mortar.
- Thickness of joints should not exceed 13 mm in any case.
- The face joints are generally raked to a minimum depth of 10 to 15 mm when the mortar in the joints is still green. This is done to provide proper key for the plastering or pointing.
Bond in Brick Masonry Wall
- No brick-bats should be used in the brick work except when it is absolutely necessary for obtaining the specified bond due to size limitations.
- Brick work is generally laid in the English bond. In all cases, it should be ensured that a proper bond is maintained throughout the work.
Quality of Mortar for Brick Masonry Wall
- Only specified mortar of a good quality should be used in the brick masonry wall, taking great care that uniform mortar joint is obtained through out the construction.
Raising of Brick Masonry Wall
- The progress of work in raising masonry should be such that all the connected brick work should be carried up in uniform layers at one level. It should be ensured that no part of the wall should preferably rise more than 100 cm than the rest of it in a day. When it is not possible, the work should be raked back according to the bond. The walls should be raised up truly vertical.
- The buttresses, counterforts etc. should be built up course by course, maintaining proper bond with the main wall and should not be added or joggled afterwards.
Use of Timber in Brick Masonry Wall
- When timber floor or roof is required to be supported on brick masonry walls, the ends of timber joists (supporting the floor or roof) should rest on corbels or brackets as far as possible. In cases where the ends of timber joists have to be built into the wall itself, it is necessary to apply suitable preservative treatment to the embedded portion of the joists and in addition some space should be left around them to minimize chances of attack by termite and to ensure free circulation of air.
Updation of Existing Brick Masonry Wall
- When an existing wall has to be strengthened by making it thicker, 20 cm × 20 cm × 10 cm. (dimensions of one brick) recesses are cut in the existing wall. The recesses are staggered taking care that one recess is made in every square meter of the wall. This enables the new brickwork to be properly bonded to the old one. This operation is termed as back-bonding.
- When it is desired to increase the length of the wall under construction at a future date, the wall is stopped with a toothed end. This is necessary to ensure continuous bonding between the old and the new brickwork.
Also Read: Your Mentor to Guide You to Buy Bricks
Expansion Joint in Brick Masonry Wall
- It is found that with an average winter-summer temperature differences of about 100 ⁰ F, a brick masonry wall expands by about 10 mm in every 30 meters length of wall. Hence it is desirable to provide minimum 18 mm wide expansion joints after every 30 to 45 meters length of wall.
Reinforcement in Brick Masonry Wall
- Half brick partition walls should be reinforced with suitable reinforcement placed at every fifth or sixth course of the brick masonry wall. The reinforcement may be in form of mild steel bars, flat bars, hoops iron, expanded mesh, or steel fabric etc.
Finishing in Brick Masonry Wall
- Plastering on brick masonry wall should be done after about 28 days of completion of brickwork. This permits adequate time for the shrinkage in masonry and concrete to take place before plastering operation is carried out.
- In works where plastering or pointing is not desired, the mortar joints should be struck flush and finished at the time of laying.
Curing of Brick Masonry Wall
- All the finished brick masonry wall should be kept wet for at least seven days.
To conclude, GharPedia recommends that the above-listed point should be followed rigorously to get the quality brick masonry work. Brick masonry wall which is constructed by following the above guidelines will definitely give you sound masonry work, which can also reduce the risk of cracks, leakages etc. in brickwork.