Easiest among the raw materials to estimate its quantity
NUMBER of CHB per SQUARE METER
Pieces in 1sqm (13pcs)
You can fit at least a total of 12-1/2 CHB inside a 1meter x 1meter wall area as shown below. Since you can not purchase a half portion of CHB you simply round off to 13pcs.
This is applicable for CHB with a size of 8" height x 16" length regardless of thickness (4", 5", 6", 8").
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| 13pcs CHB in 1sqm wall |
Using simple mathematical computations by dividing a square meter area to one piece CHB area to arrive at the same value of 12-1/2 pcs of CHB.
Dimensions:
- 8" = 0.20m
- 16" = 0.40m
- Area = 0.20m x 0.40m is 0.08sqm
- 1sqm/0.08sqm = 12-1/2pcs
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| chb area image from commons.wikimedia.org |
Get the wall area in square meters, then multiply with the number 13, and you get your needed CHB pieces on that particular wall.
For any unseen factors that may occur, you may add up 5-10% for contingency to cover up any mishandling during construction that may result to breakage of your CHB.
You can lessen the percentage of contingency depending on how you trust your contractor or "mason" who will layout the CHB.
HOW to ESTIMATE CHB PCS for WALLS (plain wall)
Sample computation:
Given wall of 4meters length x 3meters height, using 4" thick CHB
Area = 4m x 3m is 12sqm
Multiply area with 13 = no. of pieces of CHB
12sqm x 13 = 156 pcs 4" thk CHB
Contingency will be at your own discretion.
HOW to ESTIMATE CHB PCS for WALLS with WINDOWS?
For walls having small windows such as 1.0m x 1.20m or less, you may opt not to deduct this from your total computed area and will just serve as your contingency (extra pieces).
Just make the necessary adjustments per actual and have your inventory of materials listed in logbook for monitoring purposes.
Take note that this estimate is for your CHB pcs only and estimate for the mortar to bond these CHB is not yet included.
HOW to ESTIMATE CEMENT MORTAR for CHB WALLS
Mortar is a mixture of cement+sand+water and also falls to different class mixtures just like your typical concrete for footings, columns, beams and slabs except that no gravel included unless otherwise specified or required by your designer.
Class & Mixture:
- Class A 1:2 18 bags of cement, 1cu.m sand
- Class B 1:3 12 bags of cement, 1cu.m sand
- Class C 1:4 9 bags of cement, 1cu.m sand
Use this excel calculator, check in download section
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| chb mortar plastering calculator |
To summarize:
No. of pcs CHB = Wall area (sqm) x 13
+ Contingency 5-10%
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