Hub Elevations

FWIW, putting hub els on the back of lath is common in this neck of the woods.

Doesn't seem much different than setting cut and fill lines, except they assume the liability in making the elevation conversions.

We have done it both ways, giving them the cut or the elevation, but let them know that is just for the road, not the building elevations or for manholes, its not going to stop them from using it as a benchmark for other parts of the project.

I'm not so sure about the liability issues. It would seem to me the contractor would have a way to check that the point was staked to the plan grade and if he is making that check it's a good thing. Put the contractor on notice in writing that in exchange for providing the requested elevation, he must notify you of any "bust" immediately upon discovery. That should keep him from holding secret mistakes over your head later.

I have an aversion to writing hub elevations on stakes and generally will not do so, though I have made exceptions before. It's a liability thing.

We've never put elevations on stuff. Just cut/fill info and our shot #.

We do hub elevations ONLY.

> It seems that contractors seem to want the hub elevation for our layout points recorded on the back of our lath. ... Is this a common practice now days?
The other day I told a story from 1993 about a PC named Tom. Tom had me writing hub elevations on the back side of curb stake lath back then.

I generally don't write elevations on the back of the lath. Usually I write the point number, and then they can reference the plan for the elevation of that point.

I don't think I'd have an issue writing assumed elevations on there if requested, along with the cut and fill on the front side; is your main concern that there could be an error made when writing the values on the lath that would cause them to build something at the wrong elevation?

I've been doing it for years, and promote it. It typically will save phone calls, and potentially return trips - hubs get knocked out,and we even sometimes do make mistakes. Kind of a good test of how smart the contractor is too. I've even had guys want not only the hub, but to place the design grade there too (circled for clarity)

Is it really any different than providing a cut sheet for everything, that lists the point, hub, design grade and C/F. Plus any notes that may or may not fit on the lath. I prefer that, because then there is a paper trail. But sometimes they don't want to 1) wait until I get back in office to prepare it, and 2) pay for the extra office time.

I've seen contractors run design grades off a nail or hub without looking at the cut/fill on the stake. Be very clear that the elevations are not design elevations.

We put "Hub El = " on all our stakes for a construction staking project that deal with Finite layout, such as Curb, Gravity flow utilities etc. We set these features with an instrument. If its for rough grading or features that we may utilize GPS I try to avoid it or make sure the contractor is aware of the accuracy.

The old time surveyor I worked for told us never write down elevations for anything except TBMs because of liability. That was 15 years ago and since then I have been pressured by contractors to list elevations on back of slope stake RP lath. I only list elevation to nearest tenth and I tell contractors in writing that the hub elevations although correct are not subject to the double checks that typical TBM will have so there could possibly be a mistake – mathematically or transposed number etc.
I tell them that if they don’t check it against another hub to verify elevation than they are stupid and not to call me when they have problems.

Hub El =

:good: :good:

Maybe I've become one of the old time surveyors, my wife does keeps pointing out that my hare is getting grey. Hell, we used to tell them that we were not liable for one bad stake. What always makes me a little nervous is what they use these things for. If I'm laying out sub ballast with RTK my vertical is good to only 2cm per the manufacture's specs. For all I know they are using this grade stake as a TMB to run in curb. If they want a TBM they should ask for one

Besides the liablity thing, plain a simple it takes a little longer for each stake. Not much on a per stake basis but that adds up on a big project. And all of this so the contractor does not have to look at my cut sheet or plans. Yesterday a contractor actually had me give him stakes on 50' intervals at random offsets and mark the design grade only just so the could reference them without having to look a the plans.

Rant over

Gentlemen,

I appreciate the thoughtfulness in the responses to this thread.

The basic premise, as I understand it, is that if I set a stake and do record the elevation on the back of the witness lath, I am somehow responsible for any issue that may arise as a result of the use of that elevation? DUH!?

AND that if I leave the elevation off of the lath, I have no such responsibility? Not in the world I live in.

If I screw up the stake, it is my responsibility. I provided professional land surveying services that require a minimum level of care, as well as responsibility for those services. The client is paying me for that.

I have always thought it best to have a good working relationship with the contractors using my stakes. The more they know about the information I have provided, the better the chance of a successful outcome. I've been bailed out by sharp contractors, on those most rare of occasions that I have made blunders in 40 plus years.

JA, PLS SoCal

I've never NOT put the elevations of the hubs on the laths AND the elevations of the offsets and the cut/fill. If they have to run all the levels, what the hell do they need us for?

> If I'm laying out sub ballast with RTK my vertical is good to only 2cm per the manufacture's specs. For all I know they are using this grade stake as a TMB to run in curb. If they want a TBM they should ask for one
>
>

That may be the hang up. We NEVER use RTK for layout. We either get the chain out and run the buildings or bring the robot. With the robot, we lay out everything cut/fill/elevation radially, checking with a tape as we go, then move to another spot and check them all again radially and note the differences. If it's 0.015 or less, I don't fool with it. BTW, my robot is a 1" VX and it's SWEET! 🙂 I had to prove to the "old man" that radial stakeout could be done with it. He didn't believe me so I built a procedure that would catch a mistake. He liked the speed that we got with it until he got tired on a nursing home and then he didn't like it as much. 🙂

Who are we "contracting" our professional services to?

Owner of the project, or getting "bid" staking from the contractor and acting as their grade setter and grade checker?

If working for the contractor, is it the super that wants the elevations? Pipe foreman, Paving subcontractors foreman??

What type of stakes are they? What's the relative accuracy required for the layout of that particular feature of the job?

Most owners want the work done RIGHT. Most Contractors want their stakes FAST AND CHEAP!

First things first. If "bidding" a job along with the contract for a contractor to stake any features, a well defined scope of services. This should include a relative accuracy for type of staking, along with what will be called out on the lath for each type of staking. (Standard forms once produced, and easily edited for any exceptions/job types/specific clients)If the foreman then asks for something different, or more staking, that would be a change order on them, for extra time and expense over contracted conditions. This usually exposes the surveying crew and company to potential additional liability on the job. Usually there's a "gross error" indemnification thrown in for good measure for that occasional "blown" hub.

What the contractors/owners "project manager", and their field personnel need to be, is, on the same page. And, if they're not on the same page with something as simple as this, be wary.

Remember, these are the people who tried to beat you down on your "estimate" back in the main office when trying to get you onboard( or as others like to call it a "bid" for professional services ). What YOU need is a contracted estimate with a NTE clause (less than ideal, since changer orders are usually money makers), you want to haul butt and get the job done before your expenses out strip your profits. If not, your donating your time to the job.

The contractors reps in the field rarely have any worries about giving you extra work, it's just that you won't likely get paid for it without a change order of some sort. So, something that is considered as little as marking an elevation on the back of a lath may not "seem" like a big thing. BUT, as already been mentioned the biggest liability issue is not some form setter getting the grade wrong on ONE hub. Also mentioned should be when the contractor takes off from that one wrong hub and proceeds to put in +/-10k or so worth of work, then finds out it's wrong. Who do you think they'll point the finger out for "cost recovery"?

Cut sheets help error trap your staking, depending on what equipment and methodology you use ( again limiting your liability and giving the "opportunity" to perform due diligence). If they want elevations "on the fly", then double check them, and let them know it's adding time and money to the services your providing.

Get paid for your work, double check everything, charge accordingly, limit your liability with plenty of checks, perform your due diligence, and give them what they're asking for! Just make sure everyone is on the same page up front.

This and a dime still won't get you a cup of coffee or a phone call anymore..
Cheers! 🙂