Home Building Step by Step
Good planning makes like simpler when you build your home. The first step is to allocate funds for plot purchase and home construction separately from your total budget.
Important points to keep in mind while selecting plot location:
- Distance from work place, railway station, bus stand, and airport
- Availability of public amenities like road, water, electricity, drainage, etc.
- Availability of hospital, parks, recreational centres, etc.
Important points to keep in mind while purchasing plot:
- The land is not prone to frequent flooding
- There are no known earthquake faults in close proximity to your plot
- The plot should not be under any acquisition/litigation proceedings
- Check for plot survey number and ensure that land title deed is clear
- Obtain a no objection certificate for the plot from the registrar’s office
Hiring Services of Professionals
Once you have finalized the plot you can meet professionals like Architects/Engineers/Contractors, etc. for design and drawing of your home. He should be registered with the Municipal Authority. He will provide you with the plan, elevation, side and rear views of your proposed house along with steel reinforcement details.
From your hired professional you will need to get the following:
- Certificate of undertaking from Architect
- Certificate of undertaking from Structural/Civil engineer
- Certificate of undertaking from Construction Supervisor
- Structural design basis report from Structural/Civil engineer
- Certified copies of building plans
If you are engaging a contractor then specify the terms and conditions in writing to him. You must specify the construction schedule, payment terms, quality of work, quality of material like cement, sand steel, finishing & fittings, electricals, sanitary items, etc. in the contract specification.
Budgeting and Estimation
Estimates will depend on the actual design and drawing of your home and market rate of materials and labour. However, an approximate estimate can be done before that. Construction cost depends on the quality of construction and the finish you want to have. Just to illustrate – a high class finish construction can cost you as much as 50-100% higher than an economy class finish.
While you can always make a rough estimate of the cost using your judgement, it is always advisable to take professional consultation on budgeting of home construction. Generally, construction costs can be divided into material cost, labour cost and other expenses in the ratio of 60:30:10 respectively.
Cement is an important construction material and when mixed with water and other material like sand, aggregates (gitti), etc. binds them together. It is used in concrete, brick work and plaster work. Good quality cement should feel smooth when touched or rubbed between fingers. If a small quantity of cement is thrown into a bucket of water it should sink and not float. It should be free of lumps. Cement should always be kept free from moisture and water. Its storage shed should have finished floor raised atleast 150mm from ground level and should have airtight doors and windows.
Sand or Fine Aggregates :
Sand can be classified in 3 types:
- Fine sand (used for plastering)
- Coarse sand (used for masonry work)
- Gravelly sand (used for concreting)
Good sand should be well graded, clean and coarse. It should contain sharp, angular and durable grains. It should be free of any salt and organic matter. It should not have clay content more than 4 percent. Presence of moisture increases the volume of sand. For example, at moisture content of about 5 to 8 percent, the volume of sand increases by as much as 20 to 40 percent as compared to dry sand.
Stone Chips or Coarse Aggregates Stone pieces (crushed rocks) are used as coarse aggregates. Your coarse aggregate or stone chips,
- Must be clean, dense, hard, durable, and structurally sound (neither flaky nor elongated) and capable of bonding well with cement
- Should be stored properly and different fractions must not be mixed together
Steel Rods or Rebars
Rebars is the most important component of RCC structure. Concrete alone cannot take tensile loads. Steel rebars are cast into concreting to carry tensile loads. Generally rebars available in the market are manufactured through TMT route. However, the consistency in the strength of the rebar is determined by the input material. If it is manufactured via scrap route the consistency of strength along the length of the rebar is not there.
For any steel rebar weight per running metre is equal to d2/162 Kg, where d is diameter of the rebar in mm. for example, 10 mm diameter rebar will weigh 10 X 10 / 162 = 0.617 Kg/m. In India, quality and properties of steel rebars are governed by the code IS:1786 given by Bureau of Indian Standards (BIS).
Strength and elongation of rebars must comply the following standards :
You should ask for the steel supplier to verify the quality.
Water is an important as any other material mentioned above. It helps cement in hydration and distributes the cement evenly. It should be free from any salt, silt, organic compound, etc. Potable water is recommended for the purpose of construction and curing.
Foundation Work :
For designing strong and economical foundations, soil testing is very important. Bearing capacity of the soil also called soil strength has impact on the way foundation should be laid. For instance, in case of black cotton soil or soil types with low load bearing capacity, pile foundations or continuous foundations are common practice. In case if back filling is required, mooram is the best material. If it is not available then either good quality clay or sand may be used. Filling should be done in layers of maximum 6 inch thickness, sprinkling each layer with water before compaction.
Steel Reinforcement :
Plain concrete without reinforcement is like a body without bones. Reinforcement through steel rebars is one of the best forms of reinforcement to take care of all kinds of stresses generated in structure. It is advised that same type and grade of steel should be used in a structural member. Always ask your engineer to do the reinforcement detailing for earthquake resistant construction, if your house is located in seismic zone III, IV, or V. You should make sure to take the steel reinforcement detailing from your engineer. It is called Bar Bending Schedule (BBS). This schedule contains all the details of size, shape and dimension of rebars to be cut. A good BBS will help you in buying the rebars in most economical quantity and minimize steel wastage.
Checklist for steel reinforcement :
- It should be free of loose rust, oil paints, mud, etc.
- It should be cut, bent, and fixed properly
- Fixed in a position by using cover blocks, spacers, supporting bars, and laps, etc.
- It should be placed and tied such that concrete placement is possible without segregation, and compaction is possible by an immersion vibrator
Proper grade of concrete should be developed using the adequate quantities of cement, sand, stone chips, and water. For example, to prepare M 20 (1:1, 5:3 approx.) mix of concrete, you require one bag of cement, 1.5 boxes of sand, 3 boxes of stone chips and 21 litres of water. A mixer should be used to ensure uniform distribution of the material.
Concrete pouring should happen within 30-60 minutes of preparation. It should be poured in layers without breaking the continuity with maximum free fall of concrete not exceeding 1.5 metres. Lastly, compaction around steel bars and the corners of the structure should be carried out using vibrators.
Curing is the final step in completing RCC structure. It prevents moisture loss from the concrete or mortar and maintains the required humidity for reaction of cement in achieving its strength. It should be started after 12-24 hours on drying surfaces and should be continued for a minimum of 7-14 days.