Squaring a 24' x 32' building site

[jcaron2]

As you probably already know, the pythagorean theorem says the diagonal should be 40' exactly. When I do layouts, I first pick the location for one of the corners. Let's call this corner A. Then I pick the location of a second corner (let's call it B) along the long side (exactly 32' away in your case). That's the easy part. Now to find the exact location of corner C, I have my wife hold the end of the tape at corner B, and I walk out the right distance (24' in your case) to the approximate location of corner C. I stretch the tape tight and use my finger or a stick or some other pointy object and draw an arc in the dirt exactly 24' from corner B, using the tape like a compass (my wife being the point at the center of the circle and me being the pencil). You now know that corner C lies somewhere on that arc (since all points on the arc are exactly 24' from corner B) Then I have my wife walk back over to corner A and hold the end of the tape there in similar fashion. Since I know the diagonal is exactly 40', I now put my finger/stick/pointy object at the 40' mark and trace out an arc in the dirt with that radius. The point where the two arcs intersect is the exact location of corner C. Corner D is done pretty much the same way, but now you can check your work by drawing three arcs: a 24' arc from corner A, a 40' arc from corner B, and a 32' arc from corner C. If you've done everything correctly, all three arcs should intersect at the exact same point.

I used this technique to lay out my dressage arena (which is approximately 70' x 200') and all three arcs intersected within about 1/2".

Good luck!!

Josh

 

[dodge man]

I am a land surveyor and have laid out many a building, but I always have a total station (transit) to turn my angles and get them pretty much exactly 90 degrees. I then use diagonals as a check.

If using nothing but a tape, it can be done and be very accurate. JCARON2 has a very good technique and is exactly how I would do it. When you say you have a steel tape are you talking carpenters tape or a survyors 100 foot steel tape? As someone else explained, a cloth tape can have a lot of stretch. Being good at taping a measurement is harder than you think. Make sure you pull the tape tight and don't have any kink or bends in the tape. There can also be quite a bit of error in a steel tape due to the heat or the cold, but I think you can ignore that for the short distances you are using.

To refine on JCARON2 technique, I would actually layout like he described close enough to get a stake in, at least a 2" x 2" stake, bigger is O.K. Drive it in most of the way so just a few inches is sticking out of the ground. Then refine the layout on top of the stake by putting very small nails at the exact corners. Pick two of the corners and get them exact with the small nails, then do the other two, like JCAORON2 suggests and get the nails in those stakes. Our goal is to always layout a building with 0.01' which is 1/8"

 

[jcaron2]

Our goal is to always layout a building with 0.01' which is 1/8"

Great... now I feel totally inadequate for having missed by a half inch on my arena.

 

[jcaron2]

The other way I've done this in the past, by the way, which was pretty easy, was to first lay out two diagonally opposite corners (which still requires you to find the exact diagonal length using the pythagorean theorem - 40' 0" in your case). Then take a piece of string or wire (I use wire because it doesn't stretch much at all) and make a mark with a Sharpie at one end, then a second mark 32' away, then a third mark 24' beyond that one. After that it's simply a matter of putting the first mark at one corner of the diagonal, the third mark at the other corner, and pulling the second mark out away from the diagonal until the wire is taut on both sides. The second mark is then exactly at the location of the third corner. Simply walk it over to the opposide side of the diagonal, and you've got the location of the fourth corner. The only disadvantage here is that you need two helpers.

 

[nickel plate]

I think we are all giving the poster some very helpful information but some of these replys completely make my head spin. You are building a BUILDING, not a space station. Set it up and frame it using what working methods you are comfortable with. You say you have the given diagonal measurement so work with that, a framing square and the 3-4-5 (3' on one wall line, 4' on the other wall line = 5' diagonal between those two points) corner squaring method, all of which will get you four 90 degree corners with four properly dimensioned wall lengths. If you want more accuracy (as you should) kick up the 3-4-5- to 6-8-10 or even 12-16-20. When you hook your steel tape while checking the four corner diagonals, hook it as close to one of the tape's two tip edges as possible and then read the tape on that same edge plane for accuracy. You will probably wind up doing several sets of walk around adjustments until you finally get it right but that's o.k. it's your accomplishment to a complex problem using rudimentary building practices. Rember to do the exact same thing over again during the form board and stake setting phase. It's your last look before the pour.
Down the road a bit: After the slab is done, frame all of the exterior walls on the floor then invite your friends over for a wall raising and barbeque. Even the folks that have no experience in building leave with a good feeling and some new learned skills. My 32'x40' shop took about two hours to stand, brace and plumb. Good luck and keep us posted with photos.

 

[Mousefield]

This is what I did for the chicken palace a few weeks ago. It is 12ft X 28ft. I laid out the corners, managed to get them fairly close to the right dimension. In pic #1 you can see I just laid out some board to get close to what I wanted. Then the cement guy and I put a steel tape to each corner diagonally, after about 15 minutes of adjusting we were happy with the result. We did have to measure a few times to get it just right.
Square foundation makes a square building most of the time. :laughing:

 

[debo1683]

Ok, so now this really makes sense. I was mis-reading the plans provided from where I bought my building kit. The 24'x32' they calculate is with the 2x4s on the outside of the post. So my sides should all be three inches shorter. Which is why when i use the diagonal provided in the plans I am coming up short. The diagonal they give is out to out on the posts given that the post are set an inch and a half in from all corners. That makes sense in my head ... maybe not to any one else.

So, when I am measuring for framing ... I am measuring a barn that is 23' 8" x 31' 8" with a diagonal of 39' 7 3/4".

Thanks for your help guys, I would have never come to that realization without this thread:thumbsup:!

On a side note here is the thread about building my pad and cutting down trees, etc. Once the building is done, the excavator will be back for gravel and to grade everything out ...http://www.tractorbynet.com/forums/projects/166857-pole-barn-pad-long-read.html

 

[jcaron2]

Ok, so now this really makes sense. I was mis-reading the plans provided from where I bought my building kit. The 24'x32' they calculate is with the 2x4s on the outside of the post. So my sides should all be three inches shorter. Which is why when i use the diagonal provided in the plans I am coming up short. The diagonal they give is out to out on the posts given that the post are set an inch and a half in from all corners. That makes sense in my head ... maybe not to any one else.

So, when I am measuring for framing ... I am measuring a barn that is 23' 8" x 31' 8" with a diagonal of 39' 7 3/4".

Thanks for your help guys, I would have never come to that realization without this thread:thumbsup:!

On a side note here is the thread about building my pad and cutting down trees, etc. Once the building is done, the excavator will be back for gravel and to grade everything out ...http://www.tractorbynet.com/forums/projects/166857-pole-barn-pad-long-read.html

After such epiphanies I never know whether to jump for joy at having solved the problem or kick myself for having missed something so silly in the first place.

Along similar lines, I'm guessing it's a typo, but I'll take this opportunity to point out that 24' 0" - 3" = 23' 9", not 23' 8". Likewise for the long side. You'd continue to drive yourself nuts trying to get the diagonals to match if your sides are off by an inch.

 

[crazyal]

I had a problem like that once. I had my Lufkin 300' tape measuring one diag while my step brother had a Harbor Freight 300' measuring the other. The Lufkin has the white side as the 12th scale (or inches) while the yellow side is in tenths. The HF tape had one side in tenths (we didn't pay attention at the time) and the other side was metric. Every time we got the diags equal it looked 'wrong' but tapes don't lie, right. Once we figured out I was using the 12 th scale and he was using the 10 th scale things looked much better (actually we just used only my tape).

It's amazing how something so simple can get you so frustrated and how hard it is to see what's wrong once you get that way.

 

[CurlyDave]

The 24'x32' they calculate is with the 2x4s on the outside of the post. So my sides should all be three inches shorter.

In my neck of the woods a 2x4 is supposed to measure 1 1/2" by 3 1/2" . The difference in inside dimensions is 7".

Every slab I have seen is supposed to measure the same as the outside dimension of the framing. Sheathing and siding go on the outside and hang outside of the slab.