building construction
27
Nov

Important Structural Components of a Building Construction Lahore

The most important structural components of a building construction are the columns-beams-slabs made of concrete and the walls which are made of bricks and plaster. The main ingredients in concrete, mortar and plaster are cement, sand, stone chips, water, steel reinforcement etc. As a Building Contractor, I have been dealing with these materials for the past 20 years. And in any site, I always look out for the quality of these materials as that can impact the overall construction considerably.

People constructing houses can never be sure of the quality of the materials that the contractor brings to site. To help you, I shall describe some of the features you need to look out for, that indicate good quality building materials.

CEMENT

Usage of Cement in Buildings:

Cement is the binder that holds concrete and mortars together and hence it plays the most critical role in giving strength and durability to your home. It is used to make concrete for slabs, foundations, beams, columns, lintels, chhajja (sunshades), and mortar for brickwork, plastering, flooring and other such work.

Types of Cement used in house construction:

Cements used for domestic building such as your home are basically of three types:
  • Ordinary Portland Cement (OPC): A combination of clinker and gypsum.
  • Portland Slag Cement (PSC): A combination of good quality blast furnace slag (from the iron and steel industry) with clinker (which makes OPC) and gypsum.
  • Portland Pozzolana Cement (PPC): A combination of fly-ash (from thermal power plants) with clinker and gypsum.

Ideal cement for house construction:

The best cement for house construction is blended cement like PSC and PPC. But please note that good quality blended cements like PSC and PPC will take more time to set. However the final strength after 28 days will be much more.

Features of good quality cement:

  • Reduced water requirement.
  • Improved workability .
  • Less permeable to moisture.
  • Improved resistance to acids and chlorides.
  • Reduced heat of hydration.
  • Easier to finish.
  • Reduced shrinkage.
  • Reduced leaching problems because it is low on free lime.
The colour of cement has no relation to the strength characteristics. There is a wrong impression that darker color cement gives better strength. In fact, darker color cement causes the workers to add more sand than allowed in cement-sand mortar for plastering, which can then cause problems.

Selecting the right cement for your house:

It is very important that you use only a reputed brand of cement. Good brands of cement may cost 2 to 5% more but offer quality, consistency and reliability as well as 10 to 20% greater strength characteristics. Cement accounts for a mere 12 to 18% of the total expenditure on your home. So, using cheaper cement gives you little overall savings but a greater risk to the strength of your building!

The right way of using cement in construction:

Cement must be added to the concrete and mortar in a precise, consistent manner. Too little or too much cement in concrete and improper water-cement ratios cause lower strengths, shorter design life and lower durability. Never try to save on cement use by diluting the concrete mix. Remember, that by using 30 to 40 bags less of cement, you would save no more than Rs 3000 to Rs 4000.

SAND:

Usage of sand in house construction:

Along with cement, sand is a very important ingredient in mortars and concrete. Therefore the proper selection of sand is critical in the durability and performance of  the concrete/mortar mixture.
sand is a very important ingredient in mortars and concrete

Ideal Sand for house construction:

River sand is the best for construction. However due to its scarcity and exorbitant price, filter sand and manufactured sand are also used nowadays. The price of sand includes three or four components – base cost, transportation, handling and number of intermediaries. Therefore procuring sand in bulk directly from the source will be cheaper than the neighbourhood dealer, except when you need smaller quantities.

Features of good quality sand:

  • Must be clear, angular and hard.
  • Must be free from clay, mica and soft, flaky material
  • Should be graded, which means it should be a mix of fine, medium and coarse sand
  • Must be free from contaminants like sea salt.
  • Moisture (water) content must be consistent and should not exceed 7%. When mixing concrete the moisture content must be taken into consideration.

Selecting the right sand for house construction:

Even though good sand is very difficult to procure and the price is very high, it is better to use good sand rather than filter sand. But if the cost is a big factor, filter sand is available at a cheaper rate. It is sand mixed with dust/soil. Filter sand can be made better by washing off all the dust particles with water. You could also vary the type of sand that you use based on the type of work. For example, for rcc slabs, rough sand can be used whereas fine sand can be used for plastering. A simple way of checking the quality of the sand –  It should not be sticky when you hold it in your hand.

MANUFACTURED SAND:

Manufactured sand: also called M-sand is being promoted by the government as a cheaper alternative to natural sand because of the scarcity of good quality natural sand. Experts vouch that manufactured sand is not only a viable alternative to natural sand, but superior in many ways. Mortars and concrete using M-sand as fine aggregate are superior when compared to those using natural sand. The ready-mix concrete manufacturers are already using manufactured sand.

Advantages of manufactured sand:

  • The appropriate quality of rock suitable for construction can be used for manufactured sand;
  • There is no clay content in M-sand;
  • M-sand is scientifically graded to comply BIS specifications;
  • Customizing the different grades depending upon the need of construction ensures consistent quality throughout the construction cycle.
  • M-sand is half the price of natural sand.
Manufactured sand