Table of Contents
Low Cost Housing may be defined as a new concept that deals with effective budgeting and following techniques that help in reducing the cost of construction through the use of locally available materials.
Along with enhanced skills and technology without sacrificing the strength, performance, and life of the structure.
1. Low Cost Housing
There is a massive misunderstanding that low cost housing is appropriate for only substandard works and they are made by employing inexpensive building materials of low quality.
The truth is that Low cost housing is accomplished by appropriate management of resources. The economy is also achieved by delaying finishing works or executing them in phases.
2. Building Cost
The building construction cost can be divided into two parts namely:
a. Building material cost: 65 to 70 %
b. Labor cost: 65 to 70 %
c. Contractor Cost: 15% of Total Cost
Now in low cost housing, building material expense is less because we make use of locally available materials and also the labor cost can be decreased by appropriately making the schedule of our work.
Cost reduction is accomplished by the choice of more efficient material or by an enhanced design.
3. Ways to Reduce Cost
Regions from where costs can be reduced to achieve Low Cost housing are mentioned below:-
1. Decrease the plinth area by using a thinner wall concept. Example: 15 cm thick solid concrete block wall.
2. Use locally available material in an innovative form like soil cement blocks in place of burnt brick.
3. Use energy-efficient materials which consume less energy like a concrete block in place of burnt brick.
4. Use environmentally friendly materials which are substitutes for conventional building components like use R.C.C. Door and window frames in place of wooden frames.
5. Preplan every element of a house and rationalize the design procedure for decreasing the size of the part in the building.
6. By planning every component of a house the wastage of materials due to demolition of the unplanned component of the house can be avoided.
7. Each component of the house shall be inspected whether it’s essential, if it is not required, then that element should not be employed.
4. Cost Reduction Parts
The Low Cost housing can be achieved by reducing of cost of different parts of the building as follows:
Normally the foundation expense reaches about 10 to 15% of the total building and usually, a foundation depth of 3 to 4 ft. is adopted for single or double store buildings also a concrete bed of 6″(15 cm) is employed for the foundation could be bypassed.
It is suggested to consider a foundation depth of 2 ft (0.6m) for normal soil like gravel soil, red soils, etc., and employ uncoursed rubble masonry with bond stones and good packing.
Similarly, the foundation width is rationalized to 2 ft (0.6m). To neglect cracks that appear in the foundation the masonry shall be tacked with cement mortar of 1:8 boulders and bond stones at frequent intervals.
It is further recommended to consider an arch foundation in ordinary soil for effecting a decrease in construction expense by up to 40%. This sort of foundation will assist in bridging the loose pockets of soil that occur along the foundation.
In the case of black cotton and other soft soils, it is suggested to employ an under-ream pile foundation which holds about 20 to 25% in cost over the conventional method of construction.
It is recommended to consider a 1 ft. height above ground level for the plinth which may be made with a cement mortar of 1:6.
The plinth slab of 4 to 6″ which is usually considered can be neglected and in its place brick on edge can be employed for decreasing the cost. By taking this procedure the cost of a plinth foundation can be decreased by about 35 to 50%.
It is essential to carry precautions by delivering impervious blankets like concrete slabs or stone slabs all near the building for allowing to decrease in the erosion of soil and thereby neglect vulnerability to the foundation surface and crack formation.
A wall thickness of 6 to 9″ is suggested for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is recommended to employ burnt bricks which are submerged in water for 24 hours and then shall be employed for the walls.
d. Rat–Trap Bond Wall
It is a cavity wall construction with the added benefit of thermal comfort and a decrease in the number of bricks needed for masonry work.
By adopting this method of bonding brick masonry compared to traditional English or Flemish bond masonry, it is feasible to decrease the material cost of bricks by 25% and about 10 to 15% in the masonry cost.
By adopting the rat-trap bond method one can make aesthetically pleasing wall surfaces and plastering can be neglected.
e. Concrete Block Walling
Given the high energy consumption by burnt brick, it is recommended to employ a concrete block (block hollow and solid) which finishes about only 1/3 of the energy of the burnt bricks in its production.
By employing concrete block masonry the wall thickness can be decreased from 20 cm to 15 cm.
Concrete block masonry preserves mortar consumption, speedy construction of walls outcoming a higher output of labor, and plastering can be neglected thereby an overall saving of 10 to 25% can be reached.
f. Soil Cement Block Technology
It is an alternative method of construction of walls employing soil cement blocks in place of burnt brick masonry.
It is an energy-efficient method of construction where the soil is mixed with 5% and above cement and pressed in hand operated machine and cured well and then employed in the masonry.
This masonry doesn’t need plastering on both sides of the wall. The overall economy that could be accomplished with the soil cement technology is about 15 to 20% compared to the conventional method of construction.
g. Doors and Windows
It is recommended not to employ wood for doors and windows and in its place concrete or steel section frames shall be employed for performing preserving in cost up to 30 to 40%.
Similarly for shutters commercially available block boards, fiber or wooden practical boards, etc., shall be employed for decreasing the cost by about 25%.
By considering brick jelly work and precast elements effective ventilation could be delivered to the building and also the construction cost could be preserved up to 50% over the window elements.
h. Lintels and Chajjas
The traditional R.C.C. lintels which are expensive can be substituted by brick arches for short spans and preserve construction costs up to 30 to 40% over the traditional method of construction.
By considering arches of various forms a good architectural attractive appearance can be provided to the external wall surfaces of the brick masonry.
Normally 5″(12.5 cm) thick R.C.C. slabs are employed for roofing residential buildings. By considering rationally planned in-situ construction practices like filler slabs and precast components the construction cost of roofing can be decreased by about 20 to 25%.
j. Filler Slabs
They are regular RCC slabs where the bottom half (tension) concrete parts are substituted by filler materials such as bricks, tiles, cellular concrete blocks, etc.
These filler materials are so set as not to compromise structural strength, resulting in substituting avoided and nonfunctioning tension concrete, thus outcoming the economy. These are safe, sound and deliver aesthetically attractive pattern ceilings and also require no more plaster.
k. Jack Arch Roof / Floor
These can be made employing compressed earth blocks also as a choice to bricks for further economy.
l. Ferrocement Channel/Shell Unit
Deliver an economic solution to the RCC slab by delivering a 30 to 40% cost lowering on floor/roof units over RCC slabs without compromising the strength.
These being precast, construction is speedy, and economical due to the release of shuttering and boost quality control.
m. Finishing Work
The expense of finishing items like sanitary, electricity, painting, etc., alters relying upon the type and quality of products employed in the building, and its cost reduction is left to the particular preference and liking.
This was for the Low Cost housing.
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