I once saw a contractor take out a small calculator, punch a few buttons and come up with the diaginal measurements for a building to make it square.
Is there a formula for this ( shy of some complicated calculus problem) or is it a special calculator?
Moosehunter
A squared + B squared equals C squared . C is the diagonal
If your sides are 3' by 4' the diagonal is 5'.This will be true for multiples of 3 and 4 and that is a good base to start guessing when you need to find"C" and your right angle sides are not exactly multiples of 3 or 4.
Does that help?
Otherwise buy a $20 calculator .
It is a complicated formula, however, if you are just looking to square up your project just measure your diagonals. If the measurments are equal you are square, if not, move one leg of the triangle untill they are equal. Easy as that.
If you really want the calculation, it is the square root of the sum of the equal lenghts squared and there aint enough paper on my desk to run it out long hand. Most calculators today have a square root key.
You need to find the square root of "C" listed in the above post.
That gave me a headache :D.
Is the calculator a special one?
Maybe I need to take a six pack to my old math teachers house!
Moosehunter
Moosehunter,
Lets say you have a foundation 48" square and you want to find out the lenght of the hypotenuse ( the right triangle from corner to corner ). 48x48 plus 48x48 equals 4608. You need the square root of that sum ( 4608 ) enter that number on your calculator and hit the square root key ( its the one that looks like a check mark with a horizontal leg on top ) answer is 67.88 inchs.
You think that gave you a headache, here is the long hand method.//www.nist.gov/dads/HTML/squareRoot.html
:P :o
Make it easy on yourself. For each corner measure out 3' from the corner stake on one leg, place a mark and 4' out on the other leg, place another mark. If your corner is square you whould have 5' along the diagonal between the two marks. Do this for each corner. If you have been meticulous the diagonals from corner to corner will be exactly the same. If you are plotting a larger area use 9' and 12'. the diagonal between the marks should measure 15' if the corner is square.
This is what Sprucebunny said in the first reply - I have just reworded subbing actual measurements for a, b and c.
If your head still hurts, drink two beers and reread in the morning :D
The simplest way to do it is with nothing more than a tape measure and no calculations harder than simple addition.
As was mentioned, carpenters have something they call the "3, 4, 5 rule", basically if one side is 3' long and the one next to it is 4' long, the distance between the two far ends must be 5' for the corner to be square.
So it doesn't matter how big something you're building is, if you want to check for square just pick a corner and measure out one wall 3' and tap in a nail, then go out 4' the other direction and tap in another nail. Measure between the nails and adjust until it is 5' ...... (https://forestryforum.com/smile/smiley2.gif)
(https://forestryforum.com/smile/smiley2.gif)
That is what is so great about this Forum, we all learn from other people. I always measured corner to corner ? Nice to know there is a more simple method.
I learned something today.
Beetle, you're about to learn a second thing today... :D
The longer a measurement you use, the more accurate you will be because any error is averaged out over a longer distance.
Any multiple of 3, 4 & 5 will work.
If you are working on, for instance, a building 20' square, that is 5 times the 4' measure, so go 5 times the 3' measure or 15' out the other wall and measure across, it must be 5 times the 5' measure also, or 25' across to be square.
HTH
If I am reading your post correctly, therefore, measuring the complete corner to corner is the most accurate method. Therefore, I would assume that is why in the "books" they teach you the corner to corner method. Would it not then be quicker and more accurate on a 20' square building to measure your corner to corner, 28' 1/4". ::)
Does no one use "Batter Boards" anymore ???
QuoteWould it not then be quicker and more accurate on a 20' square building to measure your corner to corner, 28' 1/4".
If you are checking for square, yes, it would be quicker, but laying out, no. using 3-4-5 to lay out gives you square corners to begin with. Say if you are staking something out and simply using corner to corner, you have to adjust ALL corners to get them to final square.
My construction master IV says 28' 3 7/16". Batter boards have their place, but squaring is not one for me to use them on. They work great for reference after all corners are located. Once a straight line and a starting point are established, only 2 corners will ever need to be moved to square.
Bruce,
I agree, I have always used the corner to corner method. Its quick, its simple, and square.
Everyone's got their preference and thats ok, just like a Ford or a Chevy? ???
beetle:
Thanks for sharing that long hand method, cause I had forgotten ages ago how to do it. I'm not even sure it was simplified in this way. ;)
cheers
You guys are all doing this backward and the hard way besides. Just plan your building to be 30' X 40' and the diagonal will always be 50' and no calculator will be needed. ;D
If that isn't big enough you can make it 60 by 80. :o
30' X 50' would be better :D
Mine is 70x72.
Garges are never big enough.
Thats why I am currently building another, yet this one is two story. Its that auction fever 8)
AMEN !!! ;D (to the garage be'en too small) ;D
I always use the method of equal diagonal measurements to check for square after layout. Measure opposite diagonals, if they are equal, you're guaranteed square; if not, move things a bit until they are. The key is to figure out what to move and how far.
I cheat on the layout though. I use a Topcon total station to get my corners within 0.01' to begin with, and then work from that for more precision. ;D
FDH, I still use the tried and true batter boards and builders twine to lay out my buildings. I guess if I would take the time to learn how to use one I could rent a transit and get it down a few minutes quicker, but deep down I am just a simple ole fart ( that's similar to a G.P.I.T.A. only different :D )
Stupid question of the day time........
One, how do you know if the builders twine that you use for your layout is forming square corners if you don't calulate the corner to corner distances to check them?
Murf,
You don't which is why I use the calcualtions I mentioned earlier in this post to check for square.
What to move and how much is relatively simple.
One line or wall of the building or whatever your checking should never be moved ( reference line), measure your diagonal, if the measurement is equal you are square, if not, move the opposite line 1/2 the the differance. Lets say you measure one one diagonal is 100" the other is 101", move the opposite line parallel 1/2". you are square. One two step done.
You will have the post holes dug, posts in place, and dead square by the time the person next door has just set up his batter boards, however, I agree with one of the previous posts, they do have their place, one would be slinging mortar and bricks.
MooseHunter,
I bet you never thought your simple question would get this many responses :o Did you get the answer to your question ::)
The last large job I was on was a co-generation plant in Longview, Wa. We poured what we called a rat slab for every set of forms to be set. This was a rough 4" slab below the bottom grade. Engineers set all the corners in the concrete and forms were set accordingly. Took awhile to get used to not trying to set forms in mud or worse and getting your feet wet from the puddles on the rat slab. Solid footing for bracing etc was also a nice experience. Made 100 yard pours easy and common and the large pours[600 to 700 yards] go like clockwork no matter what the weather.
Beetle,
Got my answer and more! I will be laying out my mill shed this weekend ( if it ever stops raining) and the info gathered will be a great help.
Thanks to all,
Moosehunter