Replies

1. 
   Piffin | Feb 27, 2010 04:34pm | #1

   No, not right at all.

   That 7.5" will give you about 6" of coverage when you figure lap and waste, so you need 720 LF at least for the 360 SF of wall

2. 
   Davo304 | Feb 28, 2010 02:09am | #2

   This is "new math" to

   This is "new math" to me...converting square feet into linear ft.  Linear feet is simply the length of a board.  Your problem involving how many "sticks" of wood siding to use is easy to figure.

   You said your walls were 10 ft high....which equals 120 inches.  If you are using 7-1/2 inch wide siding, figure out how much you lose due to face overlap. One poster said you will wind up with approx 6 inch face  exposure width....if so, 120 inches divided by 6 inches equals 20 pieces. Hence you need 20 pieces of siding to vertically cover this wall from bottom to top.

   Now you say your wall is 32 feet long?  Well, how long are your siding pieces? If they are 12 feet long, then you need 3 pieces to cover the length of the wall. 3 X 20 rows = 60 pieces of 12 foot long siding....60 X 12 = 720 LF of siding for one wall.

   Now, of course that above example allowed for waste...you really only need 2.66 boards , each 12 ft long to cover the 32ft length of the wall. Hence, 2.67X20 = 54 pieces....

   54pcs X 12 ft =  648 LF Total

   Of course this last set of calculations doesn't allow for waste...always allow for waste.

   Davo

   Davo

3. 
   Gene_Davis | Feb 28, 2010 08:33am | #3

   It's neat that we can discuss math on this forum, one provided us by the publishers of Fine Homebuilding magazine.

   And there is nothing more important to fine homebuilding than having the right amount of materials at hand to do the job.

   Area is easier than volume because there are only two factors, x and y, or length by width, or height by run, or whatever you want to call it.

   So let's get started.

   Today's challenge is to figure how many boards we need to slap up on walls.  We have the measurements of our walls, and we know how wide our boards are, so let's get out our pencils, sharpen them, and begin.

   The way I prefer to look at this is to imagine a small area or our wall, one square foot, 12 x 12 inches, and see it as finished with the boards we will apply.  Finished with the cladding, I then compute the quantity it took to do that square foot, and that gives me my factor for figuring my total for the job.  I'll want to put a factor on top of that for cutting and waste and knots and more, but that is another topic.

   We have boards of 7.5 inch width up there, and I'll run through this two ways.  One way will figure it with the boards showing their full 7.5 inch width, and the other will figure it with the boards lapped so that only 5.5 inches will show.

   If we are seeing 7.5 inches of width when finished, then each 12 inches of height (if boards are laid up horizontally) will have 12 / 7.5 = 1.6 board widths showing.  And that is our factor.  If we have a total gross area of 1000 square feet to cover and finish, we will need a net lineal footage of 1000 x 1.6 = 1600 lineal feet of 7.5" boards.

   It follows that if our exposure is less than the 7.5 inches because we are lapping, and only showing 5.5 inches of width, our factor then becomes 12 / 5.5 = 2.182, and our footage requirement then computes to 2182 lineal feet.

   So it helps, this method of "slicing out" that one square foot of finished wall, and then figuring out the number of units it took to get that finish on, and using that as a factor for extending out the total.  If necessary, and it can be helpful at times, take pencil to paper and draw your square foot, and then draw on it the finish, with some dimensions.  The method for going forward will be looking right at you from your piece of paper.

1. 
   DanH | Feb 28, 2010 09:50am | #4

   Or it might work better (for some) to figure a 10x10 foot area (100 square feet), since then you have less trouble with the fractional board at the top or bottom.  Eg, 5.5" inches divided into 120 inches (10 feet) is 21.8 pieces (or simply call it 22, if you find 21.81818181818181 irrational).  So 22 times 10 is 220 linear feat in 100 square feet.  And of course divide linear feet by length of a stick to get the number of sticks.

   As to allowing for waste, I found it to be about right on our house to simply figure total square feet and then only subtract off the door areas, as if the house had no windows.  Not a hard-and-fast rule, certainly, but when I went back and did a more accurate accounting I came up with nearly the same number (and we had about as many left-over sticks as we expected).

1. 
   Scott | Mar 01, 2010 12:39am | #5

   >>>As to allowing for waste,

   >>>As to allowing for waste, I found it to be about right on our house to simply figure total square feet and then only subtract off the door areas

   Yes, and don't forget that if you have the luxury of a CAD program, the problem is greatly simplified. Any decent piece of software will calculate the cumulative area of a class of objects.

1. 
   DanH | Mar 01, 2010 08:11am | #6

   The problem is accounting for cutoffs and other waste.  If you're lucky windows will improve your use of cutoffs since where two windows are close together you can use short pieces between them.  But if the unbroken areas of the walls are the wrong length -- eg, such that you end up cutting off 17" every other board because some dimension is just longer than an even multiple of 18 -- you can end up with a lot of waste.