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  1. #1
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    Default large scale layout help

    I'm working on a commercial project where i have to do some really big layout on the exterior of the building.(approx. 40' high x 75' long) Exterior composite panels from Europe (Parklex) in a grid pattern. Plans spec out 1/4" gap/reveal between panels horizontally and vertically. I plan on shooting a control line vertically and horizontally and storypole off those lines for the rest of the layout. My question is: what is the most accurate way to establish the control lines over such a large area??? (scaffolding and fencing are in place and will be an issue at some areas)

    horizontal- transit or water level or other?

    vertical- laser or plumb bob or other?

    i have a very good quality transit and laser, but i've never used them for something this big so i'm a bit concerned about using them????

    M Smith

  2. #2
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    Default Re: large scale layout help

    I think you can do both horizontal and vertical with lasers. I would probably do each line a couple of times using a couple of different tools, and compare. If there's a place near you that rents surveyor's stuff you might be able to get something from them that will nail both lines in one try. The story pole sounds tricky... how are you going to get one that's 75' long? I would mark off the panels along your horizontal line and set the bottom course, and then stack each course up from there, like tile. I would use 1/4" spacers to gap the panels but it seems likely that there will be some variation in size and your gap will have to float a little. How are these things being fastened? Are they going to hold perfectly still while the fasteners are tightened, or are they going to want to move around?
    Bailer Hill Construction, Inc. - Friday Harbor, WA
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  3. #3
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    My question is: what is the most accurate way to establish the control lines over such a large area???
    By using parallel measurements to some feature that's already in place. Your horizontal lines should be parallel to the overhangs and window heads/sills, so I would measure from them. Same basic thing for the verticals, but instead of measuring, I'd use the laser, but just shoot it up the wall, near a corner. Again, you want to be parallel to what's existing, so just shoot it up the wall somewhere near a corner, and take a measurement up high and down low and compare them. Ideally they should be the same. If not, then just adjust as needed. Say the top measurement from the corner to the line was 2.5 and the bottom was 2, then when you move the laser over, just go with the line at the bottom, and move the top one over .5, and connect the dots.

    i have a very good quality transit and laser, but i've never used them for something this big so i'm a bit concerned about using them????

    M Smith
    Tom
    Last edited by TSJHD1; 11-18-2009 at 03:01 AM.
    1) Unconsciously Incompetent: He knows not, and knows not that he knows not. He is a fool. Shun him.
    2) Consciously Incompetent: He knows not, and knows that he knows not. He is simple. Teach him.
    3) Unconsciously Competent: He knows, and knows not that he knows. He is asleep. Wake him.
    4) Consciously Competent: He knows, and knows that he knows. He is wise. Follow him.

    May we all endeavor to progress from not knowing that we know not, to knowing that we know.

  4. #4
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    Default Re: large scale layout help

    i use a waterlevel to check a lazers accuracy.

  5. #5
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    Default Re: large scale layout help

    Use either your laser or Builders level to establish a consistent grade. You have to be creative to get around obstacles, using benchmarks off the building or offsets above the obstacle on the building. You can then move your instrument and pick up your grade off the offset or benchmark. You can use a transit or theodolite to establish vertical control lines. If the building isn't too high you can use a line laser or a drywall laser for this but I've always found an optical instrument way more straightforward than trying to find a laser line in the sunshine 40' off the ground.

    Once you get your grade and vertical control spend some time with your drawings (shop and architectural) to see how the features like windows and doors relate with your panels like Tom suggested. Take care that any changes you make in the field that deviates from either the shop drawings or architecturals can result in some nasty surprises when get to the top or out to the ends. Windows and doors can be out inches from the drawings and in relation to one another so adjusting to a single element can screw up the overall job. If you finding anything that doesn't jive with what you've got or the drawings tell the super and note the details in your log book and ask how to proceed even if you know exactly how to proceed. The architect may want the door or window moved rather than you adjusting your panels. If the super makes a judgement call get it in writing or at least document it before you change anything.

    You can use a storey pole to get grade lines up the building. Once I get my first course on I use spacers and brick lay the panels using grade lines for a check. I usually start at a centerline and work out in either direction but again that's dictated by the drawings, the material and site conditions etc. Take the time to stand back and take a long critical look at your work from time to time.

  6. #6
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    Default Re: large scale layout help

    Thanx for the replies and great info guys-

    Dave K- thanx for the thorough reply esp. about any changes that deviate from the plans and how to handle that. Had to do just that today, but now i will get super to sign off on that before i actually implement the changes we discussed. Sounds like you've done similar work and i was thinking right along the same lines as far as how to go at this "thing".

    Dave M- we're installing metal "Z's" and "Hats" as their called, vertically at all screw/rivet pattern locations- and you bring up a very good point about them moving around ???? actually was toying with the idea of spot "hot gluing" at a couple of mid points and then screw or rivet so that is minimized or eliminated as the possiblility of an accumaltion of error is very likely if i don't.

    Todd E- that's really what i was asking - what is more accurate ??? probably could start a whole debate about this subject??? Do you use the resevoir method ??? It's been years since i've used a water level, but one thing i did was add some blue or red food dye to make the water line/level easier to sight. read somewhere about adding a few drops of liquid detergent to reduce surface tension for less of a "meniscus" ?? (how the water tends to dimple or swell up the sides a tiny bit) got any tricks to share???

    I think like most i've gotten caught up in the laser technology thing and feel like water levels and plumb bobs are to "simple" or "old school" to be used in this high tech age of cool tools and gadgets. One thing i do know is that the Law of Gravity is PERFECT and man made tools, even
    lasers are NOT. Looked at some high dollar lasers and most spec out at 1/16" at 50' for accuracy which is very good but what most guys don't realize is that is what the manufacturer "claims" and is done in a very controlled setting in a lab most likely. So, in the real world that accuracy "claim" is probably more realistically twice that?? esp. with lasers as the "dot" or "line" gets fatter the farther away it gets and then your "guessing" where the middle of the red blob is and other things like the angle you look at it/sight it changes things a bit and unless your using a mechanical pencil your pencil line can be a heavy 1/16th and then snapping a chalk line on a bumpy wall can give you an untrue line if your not careful.

    So, what do you do for an accurate plumb line??

    M Smith

  7. #7
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post

    So, what do you do for an accurate plumb line??

    M Smith
    silk inkline string and a heavy bob.

  8. #8
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    Thanx for the replies and great info guys-



    So, what do you do for an accurate plumb line??

    M Smith
    PLS 5 will making a plumb line easy. Try and do it in lower light. I would consider using a story pole as some one else mentioned. Would it be possible to attach a ledger at the bottom of the wall so you could set your story pole on it to do your layout? I would use the story pole to layout the locations of the Z clips.

    A water level is a good tool, years ago I used one quite a bit. Personally, I'd use a laser level but a good transit will also work. Make sure your transit or laser level is tuned. We have a company locally for this type of thing.

    If you don't have a PLS 5 I'd use a plumb bob. Plumb and level is not the tuff part it's finding a consistent method to layout your Z clips. Like I mentioned earlier use a story pole vertically and consider using one horizontally too. I realize 75' is to long but you could use a 16' story stick to lay out as many as that length will allow, install those and then butte your stick in to the last installed panel and so on.

    How do you plan on scaffold this project..JLG?
    ~Kent~

  9. #9
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    So, what do you do for an accurate plumb line??
    I'm an old concrete guy and I've plumbed many columns and walls using a plumb bob. They are accurate as long as it isn't windy. I've used BIG plumb bobs and tricks like dropping them into a bucket of water or a bucket of oil. A strong wind on the string alone will put you out 1/4" over 16'. At the best of times you have to set it up and you have to stop it from swinging which can be time consuming.

    I'm rusty right now but I'll bet I can set up a theodolite over a point in 30 seconds (it you're just setting plumb lines you don't need to be over a point). I can sight a point at the base of the wall about 20 seconds to a minute after that and I will find the top of the 40' wall and get a point accurate to the width of a sharp pencil lead in about 30 seconds to a minute depending on the sharpness of the guy on the roof.

    There is always a chance that even a well maintained theodolite is out of wack. After you establish your line you can do a quick check by doubling. You flip the telescope, turn a 180 degree angle back to the original telescope position, zero in on your bottom mark and then find the top mark. If you're right on you're 100% if you're off the mark a little (like 1/8" or so) split the difference and you should then be 100%

  10. #10
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    Default Re: large scale layout help

    Quote Originally Posted by dave_k View Post
    There is always a chance that even a well maintained theodolite is out of wack. After you establish your line you can do a quick check by doubling. You flip the telescope, turn a 180 degree angle back to the original telescope position, zero in on your bottom mark and then find the top mark. If you're right on you're 100% if you're off the mark a little (like 1/8" or so) split the difference and you should then be 100%
    I do the same thing with a laser- works to some extent in both plumb & horizontal orientations.
    http://www.lavrans.com

    "He uses statistics as a drunken man uses lamp posts; for support rather than illumination." -Andrew Lang

  11. #11
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    Default Re: large scale layout help

    I find myself in this position allot. The plans aren't definitinve, the Architect or engineer isn't readily available and you need to make a decision to keep progress moving. If there's a conflict I will answer my own question with the following qualifier. "unless directed differently , we'll proceed in this manner". Typically, I'll fax a sketch to the PM, Architect and anyone else involved. I can't remember anytime that this hasn't initiated a response or at the least, never had it come back to haunt me if you have a record of what you proposed and the reasoning behind it.


    Quote Originally Posted by dave_k View Post
    Use either your laser or Builders level to establish a consistent grade. You have to be creative to get around obstacles, using benchmarks off the building or offsets above the obstacle on the building. You can then move your instrument and pick up your grade off the offset or benchmark. You can use a transit or theodolite to establish vertical control lines. If the building isn't too high you can use a line laser or a drywall laser for this but I've always found an optical instrument way more straightforward than trying to find a laser line in the sunshine 40' off the ground.

    Once you get your grade and vertical control spend some time with your drawings (shop and architectural) to see how the features like windows and doors relate with your panels like Tom suggested. Take care that any changes you make in the field that deviates from either the shop drawings or architecturals can result in some nasty surprises when get to the top or out to the ends. Windows and doors can be out inches from the drawings and in relation to one another so adjusting to a single element can screw up the overall job. If you finding anything that doesn't jive with what you've got or the drawings tell the super and note the details in your log book and ask how to proceed even if you know exactly how to proceed. The architect may want the door or window moved rather than you adjusting your panels. If the super makes a judgement call get it in writing or at least document it before you change anything.

    You can use a storey pole to get grade lines up the building. Once I get my first course on I use spacers and brick lay the panels using grade lines for a check. I usually start at a centerline and work out in either direction but again that's dictated by the drawings, the material and site conditions etc. Take the time to stand back and take a long critical look at your work from time to time.

  12. #12
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    So, what do you do for an accurate plumb line??

    M Smith
    Square off of your accurate horizontal line.

    Tom
    1) Unconsciously Incompetent: He knows not, and knows not that he knows not. He is a fool. Shun him.
    2) Consciously Incompetent: He knows not, and knows that he knows not. He is simple. Teach him.
    3) Unconsciously Competent: He knows, and knows not that he knows. He is asleep. Wake him.
    4) Consciously Competent: He knows, and knows that he knows. He is wise. Follow him.

    May we all endeavor to progress from not knowing that we know not, to knowing that we know.

  13. #13
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    Default Re: large scale layout help

    Thanx again for great info!!-

    Tom- what method would you use ?

    Norm- like your reasoning on how to proceed when no "decision maker" is at hand

    Dave K- never heard of a "Theodolite"- seems like a step up from a transit in terms of accuracy

    Kent B- no PLS5 - typical scaffolding is already in place, so you feel the laser is more accurate than a water level??

    Todd E- where does one get a "silk inkline string" ? any tricks to sight/transfer/mark the stringline when it's an inch or so off the face of the building? keep in mind this is a typically wood framed and "vapro shield" wrapped 40' high building. Have you ever used the "bob" in the bucket of water trick??

    M Smith

    p.s.- no one has proclaimed which is more accurate and why???? so i will start by stating firmly that while lasers are very convienent i think plumb bobs and water levels are the most accurate way to establish level and plumb!!!!!

  14. #14
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    p.s.- no one has proclaimed which is more accurate and why???? so i will start by stating firmly that while lasers are very convienent i think plumb bobs and water levels are the most accurate way to establish level and plumb!!!!!
    Sure, plumb bob is most accurate if there is no wind. Then marking off the perfect plumb line would be just as accurate. But you've got to have no wind at all, and marking the base of the string line is the tricky part about that- if you move the string a hair, your horizontal line is going to be out. Water level is probably the most accurate for horizontal, then you measure off that for plumb- more accurate than a plumb bob (no wind problems, only user error).

    Optical to laser- no difference. Optical generally uses the same mechanisms to level, and that's where all the accuracy is. Rotate 180º and you can find center. Laser line spread isn't a problem- you should be able to get within 1/64 of the center of the line, which is going to be as accurate as a transit or theodolite.
    http://www.lavrans.com

    "He uses statistics as a drunken man uses lamp posts; for support rather than illumination." -Andrew Lang

  15. #15
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    Default Re: large scale layout help

    Quote Originally Posted by M Smith View Post
    Thanx again for great info!!-


    Dave K- never heard of a "Theodolite"- seems like a step up from a transit in terms of accuracy

    Kent B- no PLS5 - typical scaffolding is already in place, so you feel the laser is more accurate than a water level??



    M Smith

    p.s.- no one has proclaimed which is more accurate and why???? so i will start by stating firmly that while lasers are very convienent i think plumb bobs and water levels are the most accurate way to establish level and plumb!!!!!
    Theodolite and transit are the same thing except that is sounds better.

    I would say a laser is more accurate because it has less chance for human error. Plumb bobs are very accurate as long as the wind is calm. The wind doesn't effect a laser so again no human error.

    Set up the laser and establish your level line...done. Use the pls 5 just like you use your plumb bob. I would set the pls 5 two inches in front of the wood frame wall put some one on the roof with a speed square find the laser dot...done.

    If you use a water level...make sure there are no air bubbles in the line.
    ~Kent~

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