Originally posted 2017-04-11 09:01:32.

HOW TO ESTIMATE THE COST OF BUILDING A HOUSE (page 1)

It is important to how much a building could cost from the beginning before initiating the project, the reasons for some uncompleted building projects are as a result of not taking time to calculate the possible amount of money that could go into building before it could be completed to a point someone could rent it out or inhabit it.

Many people make the mistake of starting a building project without proper calculations in regard to their monthly income and the specified duration the building could be ready according to their monthly savings and the total cost for the building.

The following are the steps needed for easy calculations of an amount a building could cost in naira value:

HOW MANY WALLS

Check the design of the building check how many walls that the building would have, walls means the places blocks will be raised to make up the entire building.  The number of the walls will determine how many blocks that will be needed to erect all the walls altogether. If the total walls for a three bedroom flat are 15 walls altogether. The standard height of every building should be between 12feet to 15 feet height, and every block is made with 1 feet height and 2 feet breadth, while its widths ranges from 5inches up to 12 inches i.e. (0.42 feet to 1 feet), so with this we can obtain the total number of blocks needed to erect the entire walls; below is the procedure to take:

Take the measurement of each walls length and height and calculate it by the simple formula for AREA=length x breadth assuming the value for a particular wall is length 20feet and height 15feet then the number of blocks needed to erect such wall will be (20 X 15)/(1 X 2)= 300/2=150 blocks required for that wall, do this to all the walls in the design and sum up the total to get an accurate number of blocks you will need for your building project and then consider which size of the block thickness you may need ranging from the 5inch to 12inch and obtain the price of each from block molding industries, for example, if 5inch block is sold for N100 per block, then the price of blocks needed for the wall calculated above is N100 x 150= N15, 000.

THICKNESS OF BLOCKS NEEDED

Just as earlier mentioned the thickness of the blocks needed in a building depends on the overall height of the building. If a building is to have multiple floors over one another such as upstairs of one or two stories, the initial floor which constitutes the foundation of the building may have its walls laid by 12inch blocks, while the second floor which is referred to as the decking of the upstairs may have its wall raised with 9inch block, and so forth. So the keyword is that the taller the building the more the sequential arrangement of blocks according to the inches to attain the height, the raising of walls will always start from bigger inches blocks to the smallest in respect to the height from the floor to the roof.

A situation where the building is not an upstairs may be a bungalow or a simple duplex that the total height does not exceed 30 feet the walls of the building may be raised by 9inch or 6inch blocks depending on the money available with the builder and the quality of building the individual wants to achieve.

THE HEIGHTS OF THE WALLS

The height of the walls of the building is another thing to consider, the average height of most building wall is from 11 feet to 13 feet depending on the land topography of the building and the type of the building.

A bungalow may have the height mentioned above, but many upstairs and duplex have a lesser height in their walls for each floor, because if they are to have such height on each floor it could make the building very tall and incur more cost of building to the builder. Therefore, some of them have their height limited to 11feet or less.

Your calculation should be based on the total height of the walls the building will have after it has been completed.

CEMENT PER WALLS

A good block layer can estimate accurately the number of blocks that can be laid on the building walls per a bag of cement, this number of blocks are used to divide the total number of blocks calculated for the entire building walls to give you the total number of the bags of cement required to lay all the blocks on the building walls.

SANDS PER WALLS

Though most builders do not measure the quantity of sand required for raising the walls of the building due to the fact that it is readily available and cost less than other building materials, but for the purpose of economics management in building it becomes necessary to know the actual quantity of sand needed for the raising of the entire walls of the building. If 4 wheelbarrow of sand was mixed with a bag of cement to lay about 100 blocks it means that the total number of blocks for the building would be divided into 100 blocks and the result is multiplied by 4, to give the total number of wheelbarrow of sand needed to raise all the walls of the building. So the wheelbarrow of sand is now used to make an order on the quantity of sand needed.

STEEL RODS NEEDED PER WALL

The steel rods are used for the supports in the building, they are used for the making of pillars and lintels both for the doors and windows and for the chaining of the building.

Obtaining the total quantity of rods needed for a building may be easy if a careful approach is employed during your calculation. If the beams were to be tied in angle design it means 3 rods per pillar or wall for the lintel work, but if the beams are to be formed in rectangle design it means 4 rods for a pillar or lintel on the wall. The total length of all the walls are put together to measure it with the lengths of rods which are mostly 38 feet to 40 feet in length, the total number rods for the total lengths of the building walls will be multiplied into 3 time or four times depending on the design the building pillars and lintels would carry.

Note, that sizes of steel rods used in building vary according to the size of pillars and the height of the building, which also includes the type of the building. For a bungalow and small duplex the steel rods may be from 10mm to 14mm rods, also note that the smaller the size the number of rods needs on the beams of the pillars and lintel but larger sizes require either three or four rods per pillar or beam.

ESTIMATED NUMBER OF WOOD BOARDS

The wood boards will be needed for the making of the lintels and pillars. Before the pillars or lintels are made they are first shaped by the action of wood fixed together with nails and the inside space of the wood board is confirmed to be in accordance with the actual shape required for the pillar or lintel.

Obtaining the total number of wood boards needed for a building is simply dividing the total lengths of the walls of the building with the length of a particular wood board and then multiply it by two. let’s assume that the total length of the building walls is 5000feet, and a single wood board is 15feet, therefore the number of wood board required for such building would be, 5000/15 =334 wood boards, therefore multiply it with two because the boards will be on the either sides of the walls, so it becomes 334 x 2 = 668 wood boards.

HEIGHT OF THE ROOF AND WOOD REQUIRED FOR IT

The height of the roof determines the number of wood required as well as the sizes of the woods for the roofing of the building.

The modern buildings do have from 9feet up to 15 feet heights depending on the design of the building. The widths of the roofing sheets are what determine the space that will be created during the skeleton work of the roofing so to obtain the quantity of wood the building will need, simply calculate the lines that the wood would make on the skeleton of the roof by  assuming the width of the roofing sheet to be 4 feet, therefore at every 4feet gap there will a line of wood in it running from the up to the down of the roofing design, the same is applied to every segment of the roof, and then sum up the lengths obtains, by 16 feet which is the market length for 2 by 2 plywoods currently sold at N300 for one, also take the length of all the building walls to obtain the number of 2 by 4 plywood that will be laid on the top of the wall on the surface of the last blocks and divide it by 30 feet the usual length of 2 by 4 ply woods to obtain the total for it.

The next step is to calculate the size of 2 by 4 ply woods that will be used in lifting the heights of the house, another calculation will be the 2 by 4 ply wood that will be running across the width of the entire building at each line created by the 2 by 2 ply wood. The number will be determine by the height of the roof and the number of lines created by the 2by 2 plywood and this also will depend on the width of the entire building.

Additional woods can approximately be added in the case of joining and unforeseen designs.

Note, that the above calculation is with the exception of the roof for facial boards, and the wood for ceiling of the roof.

(THIS IS JUST THE PAGE ONE CHECK THE FOLLOWING IN THE NEXT PAGES UNDER THIS CATEGORY) 

NUMBER OF ALUMINUM FOR ROOF

NUMBER OF ALUMINUM FOR FACIAL BOARDS

NUMBER OF WOODS FOR FACIAL BOARDS

NUMBER OF WOODS FOR PVC CEILING SKELETON WORK

COST OF PVC CEILING AND FIXING COST

COST OF ONE BUNDLE OF PVC CEILINGS AND QUANTITY PER ROOM

COST OF PLASTERING SAND AND PLASTERING

COST OF PAINT AND PAINTING

COST OF ELECTRIFYING THE HOUSE

COST OF TOILET SEATERS

COST OF SAND FILLING

COST OF GERMAN FLOORING

COST OF TILING A FLOOR

COST OF TILES

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