# If i want to build a structure 30ft h x 30wx40L out of blocks that are 8x8x16 how many blocks would i need ?

I figure 4635. One needs to remember the blocks are three dimensional, for example, when one side is blocked up, 8" of the perpendicular walls are already done, so simply dividing the wall area by the area of one block is not accurate.
One important question is, is this actually an engineering question, or a math question? If a construction engineering question then one does need to allow for waste, also one need to realize that 30ft high by 40ft long is a lot for a single block thick wall, reinforced columns will probably need to be incorporated into the wall, requiring more blocks
How many windows and doors?
421.875... 30ftx30ftx40ft is 432000 square inches. Each 8inx8inx16in block is 1024 square inches. 432000 divided by 1024 is 421.875
4,312 pcs of 8x16 block

Depending on how many rough openings (doors, windows etc) the gross area would call for about 4,200 SF. deduct the rough opening to come up with a block sub-total (example X windows @240 SF total surface area & X doors @320SF surface area= 3,920 SF block sub-total)

Multiply the block sub-total by 1.10 (figure 10% waste)

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