Construction Technology

Building Technology

COSTFORD constructions are the results of scientific and rational study of the pre-existing techniques and approaches of constructions. With each technique used, utmost priority is given to strength and then to its appropriate application based on the property of the material. We truly believe in the honesty of use of material and not masking it again with texture or color of other materials, which simply does no justice, either to itself or to the material it has engulfed.

Our first line of action still remains, saving energy, materials, and cost by using less energy-intense materials and more indigenous materials, which, apart from probably being cheaper, are environmentally more responsible.

Technical innovations also include mud stabilizers, combination mortars, bamboo reinforced surface beams, arch designs, and SUBO septic tanks.


Construction philosophy

COSTFORD believes the design and construction techniques used must be either indigenous to the local architecture or a more refined form of it. It is because these techniques, methods, and use of materials date back centuries and are most apt for that particular place. We believe the Gandhian principle "materials used for a construction of a house must be available within 5 miles radius of it" forms the major founding stone of our attitude and construction techniques.

All clients and agencies receive customised attention to their site, aesthetic, and budgetary requirements guided by COSTFORD's hallmark cost-effective, energy efficient approaches to creating the built environment. Natural factors such as building orientation, wind direction, vegetation, drainage, and contours of the land along with awareness of locally available materials are factored into project programming. In slum rehabilitation and rural development projects, COSTFORD provides detailed survey and programming assistance that encourages community participation in all phases of project development starting with evaluation of current housing, water supply, electricity, access to roads, and sanitation. There is also assessment of socio-economic factors such as population, density, community features, relationships, education, occupations, health conditions, medical facilities, and other community amenities.

  • Rat-trap Bond
  • Jali Wall
  • Filler Slab
  • Frameless Doors and Windows
  • Rubble Masonry
  • Arches
  • Lintel
  • Bamboo Construction
  • Flooring
  • Mud Construction
  • Built in Furniture
  • Half Brick Wall







  • Rat-trap Bond

    This double-wall technique uses bricks on edge with a cross brick between each and produces a 9-inch thick wall with an insulating air cavity in between. Surprisingly, this technique reduces the number of bricks required by 25%, thereby reducing material used, including mortar (1:8 mix), and overall cost. Rat-trap technique is equal to the strength of a solid 9-inch wall in either Flemish or English bond.

    Finishing of such walls is not generally required and exposed brick themselves are appealing and form beautiful patterns. This saves the cost of plastering, painting, and maintenance. But the sizes of the bricks vary, so only one surface of the wall can be even. The other face (generally inner) can be smoothed by patch pointing. By avoiding unnecessary plastering, we can save up to 10% of the brickwork cost.

    Jalli Wall

    Creative bricklaying is a defining visual characteristic of COSTFORD buildings with varied arrangements providing natural ventilation instead of costly and environmentally damaging air conditioning. Jali walls also provide privacy, security, cost reduction in windows needed, and – most dramatically -- aesthetic appeal.

    Filler Slab

    Lightweight, inexpensive materials such as lowgrade Mangalore tiles, bricks, coconut shells, glass bottles, etc. are used as filler materials in filler slabs to replace the redundant concrete in tension zones.

    These materials are laid in the grids of steel reinforcement rods (6mm or 8mm dia.), and concreting is done over them. The concrete mix used is 1:2:4. The grid size depends upon the design, span, and the material used. For Mangalore tiles (size 23cm by 40cm), the grid size is 33cm by 50cm. The slab thickness is 10 centimeters.

    This technique saves energy-consuming concrete. Roofs and intermediate floors account for 20-25% of the total cost of the house. This roofing costs 30-35% less than conventionally used concrete roofing. Thus a considerable amount is saved in terms of materials, energy, and cost.

    This technique also reduces the unwanted dead load of roofing. Compared to other roofing systems, it is thermally comfortable and has no health hazards. Galvanized iron and asbestos cement sheet roofs dissipate too much heat and are difficult to live under. Also, asbestos cement sheets are long associated with diseases such as lung cancer, hence must be avoided.

    Frameless Doors and Windows

    Door and window frames are not actually required. They are responsible for almost half the cost of timber used. Avoiding frames considerably reduces the cost of timber.

    Door planks are screwed together with strap iron hinges to form doors, and this can be carried by holdfast fittings carried into the wall. The simplest and most cost-effective door can be made of vertical planks held together with horizontal or diagonal battens.

    The simplest frameless window consists of a vertical plank (9” wide) set into two holes, one at the top and one at the bottom. This forms a simple pivotal window. Wide span windows can be partially framed and fixed to walls or can have rows of pivotal planks.

    Rubble Masonry

    Random rubble masonry is extensively used as foundation at places where stones are readily available. An 18” (45 cm) foundation base is adequate for most soils and single or double storey buildings. Depth and size may vary with the addition of number of floors. In case of weak soil, the trench can be widened (50-60cm) and the bottom can be laid with concrete (1:2:4) followed by a 30-35cm wall.

    For the foundation, a trench 50 cm wide is dug and laid with rubble. It can be dry masonry or mud mortar. For higher masonry walls, cement mortar (1:10) can be used. (It is always wise to pile the excavated soil between the plinth walls to prevent cost of future filling).

    Proper joints (dovetail) must be provided for stronger bonds as in the case of any other masonry works. Stones must be large in size and the gaps between stones must be filled with smaller stones for proper bonding and stability. Care must be taken to ensure bonding of stones along the length of the wall. Bamboo in lime concrete can be used for foundations, especially in the sandy areas along the sea coast. It is resistant to sea water. It remains intact whereas other foundations will crack with shifting sands. For places where stones and bricks are not available, foundation for mud walls can be of moist soil with layers of split bamboo reinforcement inserted.

      

      

    Arches

    One of the most effective ways of spanning an opening is by constructing arches. Arches can be a cost-effective alternative to the lintels. In addition, they look more appealing than flat and dull lintels. Arches ca be of different shapes and sizes depending upon span and availability of skilled masons. Most common arch shapes come in semi-circular, pointed, corbelled, and bell shapes.

    The easiest of the arches is the corbel arch. It can be constructed without any framework and needs less skilled labour. Each row of bricks projects 4-1/2 inches beyond the course below it, until the bricks meet together in the middle. Corbel arches can span openings up to 5 metres. Flat brick arches can span openings up to 1.2 metres.

    Skilled labour and framework are two essentials in construction of arches. Arches are provided not only in brick houses, but also widely used in mud arches.

    Lintel

    In general, lintels are not required over doors and window openings, up to four feet in width. This is because the actual load on the lintel is of the small triangle of masonry just above it. If required, two rows of bricks on edge are placed along the length of the opening, on either side. The space between the bricks is filled with R.C.C. of mix 1:2:4 and 6mm or 8mm dia. bars can be used.

    This kind of lintel saves cement and steel and costs almost half the conventionally used R.C.C. lintels.

    Bamboo Construction

    For most parts of the India, bamboo is a locally available material and has been used as building material for centuries. It can be easily grown and is one of the cheapest construction materials. A good bamboo cut into strips has the tensile strength almost equal to that of steel.

    It is used for reinforcement, shuttering, scaffolding, roofing, piles, filler material and much more.

    Bamboo in lime concrete can be used for foundations, especially in the sandy areas along the seacoast. It is resistant to seawater and remains intact whereas other foundations will crack with shifting sands. For places where stones and bricks are not available, foundation for mud walls can be of moist soil with layers of split bamboo reinforcement inserted.

    However it needs experience to know about the quality of the bamboo and it is difficult to calculate the exact strength of slabs with bamboo reinforcements.

    Flooring

    Flooring is often of terracotta tiles or colour oxides. The bed is made out of broken brickbats (this saves wastage of brick), over which a 3” mortar layer is laid and tiles are placed over it. Various patterns and designs are worked out, dependent upon shape, size of tiles, span of flooring, and clients’ personal taste.

    These tiles require little maintenance and are cheap. Also the patterns of tiles are visually attractive. Most commonly, tile shapes include square, rectangular, hexagonal, triangular or can be customized. Also, electrical cables can be run through these floors.

    Another method of handling flooring is poured cement with colour oxide finishes, usually in red, black, or ochre, and sometimes with red for most of the floor and black as a border.

           

    Mud Construction

    Very few houses are built entirely of one material. For example, only dense forest areas where wood seems plenty are piles, floors, walls and roof all made of wood. A concrete house has a concrete frame and slabs, but walls are often infillings of bricks or glass or metal sheeting, etc. A brick house usually means only walls are of brick, but floors and roofs are of other materials, and so on. So when you think of a mud house, do not expect to make the entire house of mud (though it is a possibility!). Bricks use a lot of fuel to burn them; stone needs quarrying, shaping and transporting. Concrete needs a great deal of energy to make the cement and then skilled labour to turn these materials into concrete. But in many parts of the world mud is right there on the site as an old, well-tried wall building material. All that is needed is the human-power to convert the ground on which you stand into a wall to surround and protect you.

           

    All over the country mud of some sort or other is found. Even if the surface soil is unsuitable for wall building, there may be suitable mud beneath, or by adding stabilisers your mud may be made suitable. Compare this situation with the burnt brick industry. Comparatively few areas have suitable mud for the purpose of burning mud into a burnt brick. So the ideal is to find mud on your own site. If this is not possible, bring it from as short a distance as possible, or find the nearest stabiliser available and then you only have to transport that to your site.

    One of the greatest problems to face during the next fifty years is that of energy. The pressure of this problem will be less if we can make use of energy-free materials as much as possible. One of India's major tasks is to provide homes for at least 25 million families who have no home. If we are to build with burnt bricks and concrete and steel, etc., we add to this vast energy problem, and to the overall cost of housing millions of families. If only we will apply our twenty-first century know-how and techniques to our age-old mud, we can solve this housing need without adding to this energy problem. So, don't just say, "Mud is old fashioned." You can make it the latest fashion-mode!

    Built in Furniture

    Much of the furniture used by COSTFORD is built-in. These are either of brick or rubble masonry raised above floor level. Raised rubble masonry with finished surface can act as sitting or tables or even beds. Brick furniture is generally finished with a red or black oxide layer. To make it interesting, tiles are fixed to these oxides to form an integrated design pattern. Bay windows, outdoor sittings, loft beds, study tables, etc. are common examples of built-in furniture.

    Recesses and buttresses in walls are used as shelves, almirahs and cupboards. Common thoughts behind this built-in furniture are that, after constructing houses and buildings, clients are left with very little money to buy costly furniture, so these built-ins save money and also provide strength to the walls.

    Half Brick Wall (Four & Half inch thick wall)

    A four-and-a-half inch or half brick wall is ad quate for small, single storey houses and is apt for partition walls. These walls are adequately strong up to a span of 2 meters. However, an isolated, long, half brick wall may fall, get knocked over, or get crushed by roof load. The stability of the wall can be ensured by providing buttresses or recesses. Also the junctions of these walls increase the stability. Thus the stability of these walls greatly depends upon designing and planning.

    Half brick walls, apart from being efficient, are also economic as they use almost half the number of bricks and even less mortar than used for full brick walls. They also save the labour charges, as they are less time consuming and easier to build.


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