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What number of woods & Roofing sheets can be used for a 100X50feet Square building?

DWQA QuestionsCategory: Civil and BuildingsWhat number of woods & Roofing sheets can be used for a 100X50feet Square building?
Tolu omosebi Staff asked 2 years ago

please sir, I want to know the numbers of woods And roofing sheets that will roof a building by 100by50 feet... Thanks so much

3 Answers
Philip N. @ Staff answered 2 years ago
Thank you for seeking an answer in Please, what is the roofing height, and the type of roofing sheet you intend to use?
Tolu omosebi answered 2 years ago
Thanks for getting back to me, The height is like 10feets tall Is for church Just left and right roofing No design For roofing sheets, coloured zinc That one that looks like normal silver zinc but colour blue
Philip N. @ Staff answered 2 years ago
Good. Let us deal with your question mathematically depending on the design of your roofing and the roofing sheet you will be using. The type of roofing sheet determines the space of the nailing points. For instance, metro tiles and coated tiles have close nailing points than long-span aluminum roofing sheets. So if you are using long span roofing sheet calculate the 2X2 wood by the number of the total cross-section of the roofing skeleton. That will be where the nails will fix the roofing sheets. Assuming 100feet is the Front and back section of the roofing and 50feet is the side sections of the roofing. Calculating the Front and back-Section At the front and back, for any point, that roofing nail will pass you will need 100feet length of 2X2inch wood. The total number of nailing points will be according to the roofing height. Some roofing can have about 15 to 20 nailing points per section. In that case, the total nailing points for the front and back will be around 30 or 40 points the same will be applicable to the points by the sides but the lengths will differ. Each nailing point for the front and back will take 100feet length of 2X2inch wood, one 2X2inch wood is around 16feet in length, therefore you need 16feet X 7pieces of 2X2inch wood to get the 100feet for a nailing point = 112feet. For every nailing point, you need 7 pieces of 2X2inch wood. Assuming your roofing has 30 nailing points at the front and back, you will need 7 X 30 = 210pieces of 2X2inch wood but if it has 40 nailing points you will need 7 X 40 = 280 pieces of 2X2inch wood. Calculation of the side sections Assuming the side total length is 50 feet, you will need 4 pieces of 2X2inch wood for a nailing point (4 X 16feet = 64feet). For 30 nailing point, you will need (4 X 30 = 120 pieces of 2X2inch wood) 120 pieces of the 2X2inch wood. For 40 nailing points, you will need (4 X 40 = 160 pieces of 2X2inch wood). Total Number of 2 by 2 plywood Based on the above calculations, you will need the following number of 2X2inch wood: For the Nailing point of 30:  213 pieces for the front and back, 120 pieces for the two sides. TOTAL = (213 + 120 = 333pieces) For the Nailing points of 40: 280 pieces for the front and back,  160 pieces for the two sides. TOTAL = (280 + 160 = 440pieces) NOW LET US CALCULATE THE NUMBER OF 2x4INCH PLYWOOD The 2 by 4 is the major wood used in making the roofing skeleton. It is laid across the building on the top of the last block. It is also raised up to obtain the roofing height as well as the overall structure of the roofing. Hence, calculation of it is very important. Assuming you will be crossing the wood at every 5 feet apart. That means (100/5 = 20), which means you will cross the wood 20 times using the shortest length section of the roofing design which is the 50feet side section. At 16feet per 2X4wood. You will 4pices to make one cross on the top of the last block. So, you need (4 X20 = 80) 80 pieces to make 20 crosses on the top of the last block. At the center of the vertical section, you will need 10feet into 20 pieces for the raising of the height at the center of the 20 crosses made on top of the last blocks. Which will be  (10feet X 20 = 200feet.   200/16feet = 12.5pieces) This will take a total of 13 pieces of 2x4inch plywood. At the vertical section of the front and back, the length from the top of the roof to the edge of the outshoots will be 27feet on both sides (you can obtain this using the Pythagorean theory: A2 + B2 = C2    Which is 102 + 252 = C2 , C= 27 Therefore you will need less than 2pieces of 2X4inch wood (16 feet X 2 = 32 Feet) for every joining of the vertical wood to the outshoot. Since the crossing is 20 times. You will 27feet length of 2 X4inch wood x 20times for the front side and the same quantity for the backside. This means 27 X 20 = 540 feet. (540/16feet = 34pieces of 2X4inch for the front side and 34 pieces for the backside. Total 34 + 34 = 68 pieces). For the two sides, 5 feet apart will be 10 times. Assuming you will be joining the sides at 5feet apart, You may need the same 27feet for each join. This will mean 27feeet X 10 for one side. Which will be a total of 270feet for one side. Divide the total feet by the length of one 2 X4inch plywood which is 16feet (270/16 = 17 pieces of the wood will be needed for one side.) You will need the same 16pieces for the other side. Therefore, the two sides of the roof will that 34pieces of the 2 X 4inch wood for the vertical joining. Another 2 by 4inches will be the ones that will be used in the crossing of the erected ones to help in holding them together. This section has no specific number rather it depends on the chosen pattern of the carpenter. If 100feet of length will cross three times at the front side and three times at the back section, it means a total of 600feet which means 38 pieces of 2 by 4inches of plywood. For the vertical crossing, let us assume 20 pieces of the 2 by 4 pieces can do it. Therefore, you will need 58 pieces of the 2 by 4 plywood for crossing and reinforcement points. You can then simply add extra 10 pieces of the 2 by 4inches of plywood in the event of extra work or reinforcement work. TOTAL NUMBER OF 2 by 4INCHES PLYWOOD For the Horizontal crossing on top of the last blocks of the building (20 times): 80 pieces For the 10feet Vertical that will be fixed at the centered to raise the building height: 13 pieces For the joining of the height (10feet) to the outshoots of each side edges: Front and back = 68 pieces, the two sides = 34pieces For the crossing and reinforcement works = 38 pieces + 20pieces = 58pieces Additional wood in case of need for more reinforcement = 10 pieces The Total number will be = (80+13+68+34 + 58 + 10=263) 263 pieces CALCULATING THE NUMBER OF FACIAL BOARD The facial board usually comes 16 feet long or 12 feet in length, Based, on the 100feet by 50feet roofing measurement, the total area will be 100feet + 100 feet + 50feet + 50 feet = 300 feet. Since one facial board will be 16 feet, 300feet/16feet = 19 pieces will be required for the roofing edges. OTHER ITEMS Other items which cannot be fixed or calculated here are the total number of nails and their sizes, the workmanship of the carpenter. COST OF WOOD 2X2inch wood has soft and hard types at the cost of N300 to N500 respectively depending on your location. 2X4inch plywood usually comes in hardwood for roofing purposes. It costs between N2500 to N3500 based on the market location The facial board usually comes in soft and hard but the recommended type for roofing is the hard facial boards which cost around N4000 to N6000 per one. Summary Note that the above calculation was made based on the 100feet by 50feet square size roofing under the basic roofing design at the height of 10feet tall. If your roofing design is different from the basic design used in this calculation the total number of woods may vary widely depending on your roofing design. Also, note that the type of roofing sheet can alter the overall number of 2 X2inch wood you will be buying.   Please read the full publication here:  
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