'Standard specification and work procedure for brickwork in masonry construction' provides guidelines about quality of bricks, mortar, soaking of bricks, laying of bricks, curing, scaffolding etc. The construction of brickwork in substructure and superstructure requires quality control on various aspects of material and construction procedure.
Work Procedure of Brickwork in Masonry Construction
1. Materials for Brickwork
The quality of bricks to be used in masonry construction should be of standard specifications (good brick earth, thoroughly burnt and deep cherry red or copper in color). Bricks should be regular in shape and their edges should be sharp. Bricks should emit a clear ringing sound on being struck and should be free from cracks, chips, flaws and lumps of any kind.
Bricks should not absorb water more than one-sixth of their weight after one-hour soaking by immersing in water. Standard bricks should have a crushing strength of 105 kg/sq.cm or 1500 lbs/sq.in.
Mortar should be of the specified grade and materials used for mortar should be of standard specifications.
For cement mortar, cement should be fresh Portland cement or pozzolana Portland cement of standard specifications. Sand should be sharp, clean, and free from organic and foreign matters. Coarse or medium-sized sands should be used for rich mortar, and local fine sand may be used for weak mortar.
The proportion of cement-sand for mortar can vary from 1:3 to 1:6 or as specified. Materials of mortar should be measured to have required proportion with measuring box. Cement and sand should first be dry-mixed to have a uniform color on a clean masonry platform and then mixed by adding clean water slowly and gradually to have workable consistency and mixed thoroughly by turning at least three times.
Only freshly mixed mortar should be used for construction; old and stale mortar should not be used. Mortar for one hour’s work should only be mixed with water so that they can be used before setting starts.
2. Soaking of Bricks
Bricks should be fully soaked in clean water by submerging in a tank for a period of 12 hours immediately before use. Soaking should be continued till the air bubbles have ceased to appear.
3. Laying of Bricks
Bricks should be laid in English bond unless specified and should be well bonded. Every course should be truly horizontal, and walls should be truly in plumb. Vertical joints of consecutive course should not come directly over one another; vertical joints in the alternate course should come directly over one another.
No damaged or broken bricks should be used. Closers should be of clean-cut bricks and should be placed near the ends of walls but not at the other edge. Selected best-shaped bricks should be used for face work.
Mortar joints should not exceed 6 mm (1/4 inch) in thickness and joints should be fully filled with mortar. Bricks should be laid with frogs upward except in the top course where frogs should be placed downwards.
Brickwork should be carried out for not more than 1 metre or 3 feet in height at a time. When one part of the wall has to be delayed, stepping should be left at an angle of 45 degrees. Corbelling or projections, where made, should not be more than ¼ brick projections in one course. All joints should be raked and faces of wall are cleaned at the end of each day’s work.
4. Curing of Brickwork
The brickwork should be kept wet for a period of at least 20 days after laying. At the end of day’s work, the tops of walls should be flooded with water by making small weak mortar edging to contain at least 2.5cm or 1 inch deep water.
5. Protection for Brickwork
The brickwork should be protected from the effect of sun, rain, frost etc. during the construction since it is green and likely to get damaged.
6. Scaffolding for Brickwork
Necessary and suitable scaffolding should be provided to facilitate the construction of a brick wall. Scaffolding should be sound and strong with supports and members sufficiently strong to withstand all loads likely to come upon them.
7. Measurement of Brickwork
Brickwork should be measured in cubic meter or cubic feet. Different kinds of brickwork with different mortar should be taken under separate items. The thickness of the wall should be taken as the multiple of half brick as 10cm, one brick as 20cm, 1.5 bricks as 30 cm and so on. The rate should include the cost of complete work including scaffolding and all tools and plants.