Basic Construction Staking

The Cali Ex-Pat

Hi All, Spent quite a while yesterday staking out a site where we are about to begin a new house. While we aren't excavators, I would like to have a basic idea of how to square up the stakes??? It's not as easy as you'd think! Is there somewhere on line that I can read up on the basic geometry behind staking?? Thanks!

neolitic

There you go!
Two tape, the diagonals of a rectangle
or square are equal when the corners are 90º.
Then there is ...a²+b²=c², or
"the sum of the squares of the two right sides
is equal to the square of the hypotenuse."

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Cache

I'll go ahead and explain one of the easier ways to do it that is essentially just an ellaboration of neolitics statement. Most house footprints are essentially just a rectangle with a bunch of juts and bump-outs. Ignore the bump-outs. Determine from your plans what size the core rectangle is. (In my case, once I got rid of the bump-outs, the core rectangle was 33' long on the side of the house, and 70' long on the front of the house.)

Then follow the steps below. I've provided my measurements on my last build to help you understand.

1. Get a 300' surveyors tape measure and a dozen 12" grading stakes.
2. Decide which property boundary you want to measure from. My last build was a corner lot and I wanted to be as close as possible to the road on both sides in order to maximize the size of the backyard.
3. Make sure if you are using the road to determine the setbacks that you are sure where the property line starts. Here, it is 12' from the road, and a minimum 25' setback which means I had to be 37' from the road.
4. On each side of the lot, measure in from the boundary the appropriate distance (37' from the road for me), and pound in a stake.
5. Run a tight string between the stakes. This should result in a string that is running parallel to the boundary.
6. Along the string you just ran, measure in from the side boundary according to the side setback (again 37' in my case, but you might not be on a corner lot) and drive a stake in. You don't need to take two measurements and run a string between them on this one. Just the single point is necessary.
7. From that stake, continue measuring along the string the full length of that side of the core rectangle and drive another stake. In my case this was the 70' front of the house.
8. Using the dimensions of your core rectangle, determine what the hypotenuese is. IOW determine what the diagonal of the rectangle is. If you aren't at all good at math then use an online hypoteneuse calculator. If I were using the calculator linked below, LEG A=70 and LEG B=33; and the resulting hypotenuse was 77.39'. http://www.algebra.com/calculators/g...ythagorean.mpl
9. Remember that the calculator can't determine inches, so you will need to convert inches into fractions of a foot. IOW, 25'4" is equal to 25.33'. Surveyors tapes usually have feet/inches on one side and decimals in the other side.
10. Add the resulting hypotenuse to the length of the side of the core rectangle that is perpendicular to the string (in my case 77.39+33=110.39'). Have someone hold this measurment on one of the front corner building stakes, and another helper hold the beginning of the tape on the other front corner building stake.
11. From the beginning of the tape, locate the appropriate measurement for the side of the rectangle. In my case this was 33'. Put a crease in the tape right there, dividing the previous summation into two sections. Pull away from the people holding their marks on the front corner stakes until both sections of the tape are tight, but don't pull the helpers off their stakes.
12. Once both sections of the tape are tight, the crease indicates where one of the back corners of the core rectangle will be. Pound a stake in there.
13. Repeat this for the other back corner by simply having your helpers trade corners so that each of them is now on the opposite front corner building stake.
14. Now you should have the core rectangle staked off completely. Double check your accuracy by measuring the diagonals of the rectangle. They should be the same, or at least very close.
15. Now that the core rectangle is staked off you can simply locate the necessary bump-outs from that.

Cache

The method I explained above would tell you how to locate and square up a building on the lot. If all you are trying to do is determine the lot boundaries on a square lot, the same method applies, but you just have to substitute the lot dimensions in for the building dimensions.

house bldr

I do it similiar to the above description but extend my stakes out past the corners several feet on each side so they don't get dug out, the you can stretch stings and plumb down and reset them in the basement after it has been dug

john1066

For us we use our total station or GPS and layout where the building is going then set off sets somewhere around 30-50 feet away depending on what is out of the work area. then we use the off sets as we are digging in order to put the corners back into the hole.

tgeb

One of the KEY things that have been left out of these responses is that when you pull measurements with a tape you also MUST be level with the other point you are checking from.

If not you will never get your building square.

You also need to work with people that understand what it is you are doing and why.

I once arrived at a site and the lead carpenter was laying out with a guy that was typically doing design and drawings. I noticed that the guy was measuring to a level held plumb and marking the layout onto the footing.

But when I spoke up and asked why he, (the new guy), was holding the tape on one side of the level and marking the footing on the opposite side, you should have seen the lead carpenter's face, they had to go back through the whole layout and correct the mistakes. Had I not dropped in when I did, the building would have been out of square a couple inches.


John1066, has probably the best method, but you probably need $75K -$150K to get his setup, then you have to learn how to use it.....

You can layout a simple foundation pretty quickly with tapes and stakes if you do the math first. It's not that hard, but you must remember to hold the tapes level.

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john1066

No your right the Gps works great but for simple stuff its easy to scale of the plans and pull tapes in to where you have to go. but i still think your better to offset everything you do so that you don't have to redo everything you did. if you put your building corner in offset it 30' to the side
to offset right tho it takes two stakes 10 feet apart in a straight line with the original point. this gives you that same location again just by pulling a tape. it works great for all applications. and the other trick with that is if you pulling 50 and 60 feet always pull from the 60 then run the tape right by 50 and you will be all set.

KHouse75

I pay my surveyor to do it.

He has a handheld HP device that interfaces with his survey equipment. We give him the foundation plan in autocad format, he loads up the plot plan on the HP handheld, loads the foundation plan and the app he uses lines the house up. He then tweaks it and starts placing stakes.

The old way we did it was a²+b²=c².

The Cali Ex-Pat

Don't know what I'd do without this forum! My employer has actually said "if I have to show you, I might as well do it myself" -- NOT super helpful!

Thanks for all your quick posts!

TMatt142

Of course you should always lay it out on it's exact point...Then offset it however much you need to. Marker paint works great!!!

tgeb

Maybe he doesn't know how to do it either.

An appropriate response from a good employer would have been, "Come on we'll do this one together, ask as many questions as you need to, you will do the next one, and it better be right."

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dlcj

first off get yourself a construction calculator. I have one by calculated industries called Construction Master IV. It is one of my favorite tools, it does everything in 5 seconds it took me a year of geometry to learn. Itll do stairs, area of circles, metric, feet AND or inches, and a bunch of other stuff. Pick it up at home depot for $50. comes in a rubber protective case too.

As far as laying out we do it like others said using a 100' tape and flags. First pull the tape to show where the front wall and front door will be and make sure everybody is happy with that. Then do your squaring from that line like everybody else said. One thing we do differnt than alot do is we do not build the batter boards till after the concrete pour. There just in the way. We square it up with flags, lay a string on the ground from flag to flag and mark it with lime and pick up the sting. We have our excavator with a 24" bucket dig with 3/4 of bucket to inside of line and 1/4 out side. Gives plenty of room to square up using a tape and level like someone said.

cexcavation

Here is an easier method that I use. Determine what you are squaring off to. i.e neighboring building, road, property line, etc. and set your initial side off of that with the appropriate setback. Once your first side is set and staked, pick a stake to pivot off of. Figure out your diaganol dimension using the Pythagorean as mentioned earlier(convert decimal to inches by multiply decimal portion by 12). Pull the tape to the eyeballed corner, set your paint can at the determined diagonal and spray as you make a reasonable arc. Go to the opposite stake, pull whatever dimension is on the plans(I typically do a 6' overdig per dimension since it never fails that someone will want to move something "just a smidge"), and wherever that intersects your arc is where you pound your stake. Repeat for the other corner using the other stake and whalla!!! Easy as pie, accurate, and very old school.......I'll have it squared before the GPS gets booted up GPS is very nice and I would love to have one, but there isn't enough money in plunking houses in the ground.

P.S. this is of course assuming a level area. In the case of hillsides, then there are a whole lot of other tricks that you often make up as you go.

dlcj

P.S. this is of course assuming a level area. In the case of hillsides, then there are a whole lot of other tricks that you often make up as you go.[/QUOTE]

You got that right. We once built a house on a hillside that droped about 8' from front to back in about 30' run (not too bad but a first for us at the time). Without fancy gps equipment we had to go ahead and build batter boards 10' tall to hold the strings. We first measured holding the tape up best we could to get a whereabouts for the batters. When we strung the strings and pulled the tape low and behold it was square right of the batt We spent the next hour measuring an remeasuring in disbelief but it was still right.

Cache

That's how my most recent one was. 11' batter boards in the front and the back ones needed to be dug down a bit.

cexcavation

If you want to save a little time and expense of using batter boards on hillsides (although this is quite effective, I've never used them), the Pythagorean theorem pulls through again. Since you know how far out you are in height, and your hillside is usually fairly even, your hillside measurement becomes "c" your height difference "b" and your actual dimension "a". Example, your house needs to be 30' and the hillside is out by 8', then your tape measurement following the ground would be just over 31' and 1/2". Your diagonals will use the same idea while your laterals will stay normal. I typically do an 8' overdig on hillsides since banks will tend to slope a little, and margin of error goes up. Once you get it down to level, recheck and make sure you nailed it. Less time, less effort, and quite effective. On smaller hillsides, a level and a plumb bob work great. Every job is different, so who knows exactly what to do until you try a few things........My advice is stick to what works best for you.

mikesewell

I usually just do it by eye. Never had a problem yet.

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dlcj

I think i've seen some of your work

mikesewell

Actually, that's quite possible if you've traveled much at all.

I would love to see some images of the 11' batter boards.

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