Buy the basic materials carefully

Cement, steel, bricks, sand and coarse aggregate are five basic materials used in raising the skeleton of a building and imparting structural strength to it. More than 50 materials are used in the construction of a building but the cost of these five materials itself is more than 40% of the total cost of a building. Howsoever attractive finishing materials we may be using, unless the cement, steel and bricks are of good quality, a building loses its net worth and soon develops signs of distress. Utmost care should therefore be taken in selection of these basic materials. Here are some guidelines:
Cement
1. Freshness : Always choose cement as fresh as possible. Manufacturers attach tags to cement bags and these tags carry the week and year of manufacture. Don’t confuse the week with the month. A tag with a 2/07 stamp means 2nd week of year 2007. Don’t read it as February, 2007. Check the date of manufacture and don’t accept cement bags more than two months old. Remember that cement absorbs moisture from air. Cement more than two months old loses a part of its strength if not stored properly.
2. Manufacturer: Manufacturing of cement has seen a technological revolution recently and the cement being manufactured by reputed manufacturers is of extremely good quality. Always select a reputed manufacturer. ACC, Birla, Gujarat Ambuja and JK are some reputed manufacturers.
3. Grade: Choose right grade of cement. OPC has three grades i.e. 33, 43 or 53. OPC grade 33 carries IS269 mark, grade 43 carries IS 8112 mark and grade 53 carries IS 12269 mark. PPC has no grading and its bags carry IS1489 mark. PPC is considered equal to 33 grade cement. 53 grade cement is strongest among all these though its cost difference is marginal. However it requires more curing and should be chosen if adequate curing arrangements are available. Consult your engineer for the cement grade or go for 43 grade cement for RCC parts of your house. For balance work, you may choose even 33 grade or PPC.
4. Weight: Check the weight of cement bags. Each full bag should weigh 50 kg. Weight of empty bag is extra. These days, plastic bags are used and these carry negligible weight. Earlier, jute bags were used for packing of cement and 500 gm extra weight was counted for them.
5. Condition of bags: Always check the condition of cement bags. These should be intact and not torn from anywhere. Generally, a hook is used by the labourers handling the cement bags. Skilled labourers don’t pull the hook after inserting it into the bags and are expert in shifting cement from one place to other without damaging the bags. However unskilled labourers, if deployed, may harm the bags causing loss of cement and making it susceptible to moisture in the atmosphere.
Steel

1. Manufacturer: Always buy steel produced by a reputed manufacturer. Quality of reinforcement steel plays a very important role in determining the life of the building. Visually, all steel lots may look the same but quality wise, these may be a lot different. Steel Authority of India Ltd. (SAIL), Tata Iron & Steel Company (TISCO) and Rashtriya Ispat Nigam Limited (RINL) are three top manufacturers of steel in India. Inbuilt laboratory arrangements with these manufacturers ensure stringent quality control checks before passing of steel for sale. Try to buy steel produced by these firms.
2. Test certificate: When a large quantity of steel is to be purchased, ask the seller to show the test certificate of the lot being sold. These test certificates are supplied by the firms and are half printed and half embossed to avoid any tampering. Reputed manufacturers also put their trademarks on the steel bars. Look for them or ask the retailer to show them to you. Locally produced steel may not be that strong and may have been produced from scrap.
3. Type of steel: Decide the type of steel to be used. Prefer High Yield Strength Deformed (HYSD) bars to round ones, as these bars are much stronger than plain or round bars. Weight wise, both weigh equally. Popular name of HYSD bars is Tor steel. In actual, Tor is a trade name belonging to Tata steel company. As Tor or HYSD steel is stronger, it saves cost. Strength of an 8 mm diameter tor steel bar is almost equal to 10 mm diameter plain steel bar. Similarly, a 10 mm dia tor steel bar has almost same strength as 12 mm plain steel bar. Further, prefer Thermo-Mechanically-Treated (TMT) bars. These bars have a soft core but hard outer surface, have same strength as HYSD steel and take better stress before yielding because of the soft core.
4. Steel for stirrups: For the stirrups to be put in beams, use plain round bars as it may be difficult to bend tor steel of larger diameters. This quantity will however be small.
5. Diameter of steel: While finalizing the steel lot, check the diameter of the steel. Steel produced has variation in diameter. Steel categorized as of 8 mm diameter may in actual have 7 mm diameter and so on. This problem generally occurs in low diameters up to 16 mm diameter. Though lower diameter will not cause a financial loss as steel is sold by weight but it may ask for a review of the structural design.
6. Condition of the lot: Choosing a lot that is free of rust is obvious. Steel is supplied in straight as well as coiled form. Prefer straight steel bars. Coiled steel requires more labour for its straightening up.
7. Work out right quantity: Prefer to work out right quantities of steel required for different diameters. Take help of an engineer who may bring saving in steel by adopting cut length method and by deciding the lengths of steel bars to be purchased. He may workout lengths of bars for different portions of the building and combines them to check the most suitable lengths that will generate minimum scrap. The number of diameters should also be kept low for practical purposes.
Happy Building!