Estimation of Construction Materials:
1. Concrete works
• Used for foundations, columns, beams, slabs (roofs), lintels, and damp prof (D.P)
• Salt resistant cement should be used for all concrete works under damp prof work level (below normal ground level N.G.L.).
• The common mixing ratios for these works are:
- (1:1.5:3): used for highly loaded parts and those exposed to bad weather conditions or water prof parts.
- (1:2:4): used for most concrete works.
- (1:2.5:5): used for reinforced and non-reinforced concrete works with low load and floors.
- (1:3:6) : used for floors and walkways.
- (1:4:8) : for bedding.
• Low load is less than 175 kg/m^2 = 17.5 Mpa.
• Moderate load is 185 – 350 kg/m^2 = 18.4 – 34.3 Mpa.
• High load is more than 35 Mpa.
Volume of cement, sand, and gravel in 1 m^3
The mixture loses 1/3 or (0.333) of its volume when it is mixed with water.
V = 0.67 ( C + S + G ) ➔1 m^3 = 0.67 ( C + S + G )
For mixture ratio (1:2:4):
1 = 0.67 ( C + 2C + 4C ) ➔C = 0.213 m^3
➔weight of cement = 0.213 m^3 x 1400 kg/m^3= 298.2 kg ≈ 300 kg = 0.3 ton.
Therefore:
Sand = 2C = 2 x 0.213 = 0.426 m^3
Gravel = 4C = 4 x 0.213 = 0.852 m^3
2. Brick works:
• Standard dimensions of a brick are: 24 x 11.5 x 7.5 cm.
• Actual volume of a brick = 0.00207 m^3
• Width of cement mortar = 1 cm.
• Construction dimensions of a brick are: 25 x 12.5 x 8.5 cm.
Volume of a brick (with its mortar) = 0.002656 m^3
• Number of bricks in 1 m^3 (Nb) =1 𝑚^3/0.002656= 376.5 bricks ≈ 377 bricks= 380 bricks.
• Volume of mortar in 1 m^3 = 1 – ( 0.24 x 0.115 x 0.075) x 376.5 = 1 – 0.00207 = 0.221 m^3
• Volume of cement and sand in 1 m^3
- The common mixing ratio is cement to sand (1:2), (1:3), (1:4)
- Cement mortar loses 25% of its volume when it mixed with water.
- Volume of mortar material in 1 m^3
V = 0.75 ( C + S )➔1 m^3 = 0.75 ( C +S )
- For (1:3) mixing ratio:
1 m^3 = 0.75 ( C + 3C ) ➔ C = 0.333 m^3
S = 0.999 ≈ 1 m^3
- For 1 m^3 of brick works:
mortar volume = 0.221 m^3
Cement volume = 0.221 x 0.333 = 0.0736 m^3➔ weight 103 kg = 2.1 bags
(each bag = 50 Kg)
Sand volume = 3 x C = 3 x 0.0736 = 0.221 m^3
Therefore, material needed for each 1 m^3 of brick works are:
377 to 380 bricks
103 kg of cement (2.1 bags)
0.221 m^3 of sand
There are many cases of wall construction using brick:
Case 1:
In this case, wall thickness ≠ any of brick dimensions (using the English or German method).
The amount of brick and mortar are estimated by m^3 as previously mentioned.
Case 2:
In this case, wall thickness = one of the brick dimensions:
a. Wall thickness = 11.5 cm.
Area of brick = 0.25 x 0.085 = 0.02125 m^2
- Number of bricks in 1 m^2(Nb) = 1 𝑚^2/0.02125= 47.06 ≈ 48 bricks .
- Mortar volume= wall volume–brick volume= 1 m^2 x 0.115 – 47.06 (0.00207)= 0.0176 m^3 .
Cement volume= 0.0176 x 0.333 = 0.00586 m^3➔ weight = 8.2 kg = 0.164 bag.
Sand volume = 3C = 3 x 0.00586 = 0.0176 m^3
Therefore, materials needed in 1 m^2 of brick wall (11.5 cm) thickness are:
48 to 50 bricks, 8.2 Kg of cement, and 0.0176 m^3 of sand.
b. Wall thickness = 7.5 cm.
Area of brick = 0.25 x 0.125 = 0.03125 m^2
Number of bricks in 1 m^2
(Nb) = 1 𝑚^2
0.03125= 32 ≈ 32 to 35 bricks.
Mortar volume= wall volume – brick volume= 1 m^2 x 0.075 – 32 (0.00207) = 0.00876 m^3.
Cement volume = 0.00876 x 0.333 = 0.0029 m^3
➔ weight = 4.1 kg = 0.08 bag.
Sand volume = 3C = 3 x 0.0029 = 0.00876 m^3
Therefore, materials needed in 1 m^2 of brick wall (7.5 cm) thickness are:32 to 35 bricks, 4.1 Kg of cement, and 0.00876 m^3 of sand.
3. Using concrete blocks (Block):
• It is a cheap material, but its thermal isolation property is not good.
• Its standard dimensions are 40 x 20 x 15 cm.
• Its volume = 0.012 m^3
• Width of cement mortar used in this type of work is 1 cm.
• Construction dimensions are 41 x 21 x 16 cm. and its construction volume is 0.01378 m^3
• Number of blocks in 1 m^3 =1 𝑚^3/0.01378= 72.6 ≈ 73 blocks.
• Mortar volume in 1 m^3 = 1 – (0.012) x 72.6 = 0.129 m^3
Cement volume in 1 m^3 = 0.129 x 0.333= 0.043 m^3➔ weight= 60.14Kg =1.2 bags
Sand volume = 3 x C = 3 x 0.043 = 0.129 m^3
Therefore, material needed for each 1 m^3 of block works are:
73 blocks, 60.14 kg of cement (1.2 bags) and 0.129 m^3 of sand.
4. Using Stone:
• Building using stones is slow, requires large amount of mortar and skilled
workers. Supplying of stone is high in cost despite of it is a cheap material.
• Dimeter of a stone is 10 to 35 cm.
• Volume of spaces in construction with stone is 25% to 30% of total construction
volume. Therefore, the volume of cement mortar in 1 m^3
is 0.25 to 0.3 m^3
• Cement volume in 1 m3 of stone works with (1:3) mixing ratio = 0.083 to 0.1
m^3➔ weight = 116.2 Kg = 2.3 bags.
• Sand volume in 1 m^3 of stone works with (1:3) mixing ratio = 3 c = 3 x 0.083= 0.25 m^3
• for 1 m^3 of stone works:
0.083 to 0.1 m^3 ( 116.2 to 140 kg ) cement
0.25 to 0.3 m^3 sand
5.Rendering works:
a. Rendering with cement:
• Common material mix ratio is (1:3) or (1:4).
• The mixture loses 0.25 of its volume when it is mixed with water.
• Volume of cement and sand in 1 m^3 in (1:3) mix ratio:
V= 0.75 ( C + 3C ) ➔ C = 0.333 m^3
S = 0.999 ≈ 1 m^3
• Volume of cement and sand in 1 m^3 with (1:4) mix ratio:
V= 0.75 ( C + 4C ) ➔ C = 0.267 m^3
S = 1.067 m^3
• For 1 m^2 of cement render (thickness = 0.02m):
V = 1 x 0.02 = 0.02 m^3
- In (1:3) mixture: cement= 0.02 x 0.333 =0.0067m^3➔ weight = 9.32 kg
= 0.186 bag.
- Sand = 0.02 x 1 = 0.02 m^3
- In (1:4) mixture: cement = 0.02 x 0.267 = 0.0053m^3➔ weight = 7.476 kg = 0.15 bag.
- Sand = 0.02 x 1.067 = 0.021 m^3
b. Plastering with gypsum:
• Gypsum loses 10% of its weight during work.
• The amount of gypsum estimated in kg for 1 m^2 = 1 m^2 x thickness x density
- Gypsum density = 1275 kg/m^3
- Plastering thickness = 2 cm = 0.02 m.
Therefore, the amount of gypsum in 1 m^2 = 1 m^2 x 0.02 x 1275 x 1.1 = 28.05 kg.
6. Tile works:
• The number of tiles in 1 m^2= 1 𝑚^2/𝑎𝑟𝑒𝑎 𝑜𝑓 𝑜𝑛𝑒 𝑡𝑖𝑙𝑒
• Width of joint = 2 to 4 mm. it can be considered to be 3 mm (0.003 m) around all tile sides.
• Thickness of cement mortar below tiles is 2cm or 3cm
• Mixing ratio is (1:3) using salt resistance cement.
• For 1 m^2 tiles works with dimensions of (30 x 30 cm):
- Number of tiles in 1 m^2 =1 𝑚^2/0.303 𝑥 0.303= 10.892 tiles ≈ 11 tiles.
- Volume of cement mortar = 1 m^2 x 0.02 m =0.02 m^3
Cement = 0.02 x 0.333 = 0.0067 m^3➔ weight = 9.32 kg = 0.186 bags
Sand = 0.02 x 1 = 0.02 m^3
7. Scarlet Tile:
▪ Number of scarlet tiles = Perimeter length / Length of scarlet tile.
▪ Mortar volume = length of scarlet works * mortar thickness (0.02 m).
8. Painting works:
There are many types of paint, each is suitable for a particular purpose
▪ Oil paints : suitable for steel parts and walls within a wet area
▪ Water paints (emotion) : suitable for interior walls
▪ Sinosim: suitable for exterior walls
❖ The amount of paint that paints number of m^2 is different according to the paint type and surface roughness. The table below shows the surface area that can be covered by one gallon of paint.
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