In 95 percent of the cases a tech crew will do the field work. They simply need to be employed by a professional with competency to guide them correctly and then understand the words in the Instructions before applying the official signature and stamp (and accepting the liability for any errors or misinterpretations). Architects, some varieties of engineers and land surveyors have the requisite training to guide tech crews and the comprehension skills to do the remainder. Through their licensing process they have accepted a duty to the public that the tech crews do not possess.
I'm just a Party Chief, but this is how I collect data for an EC.
- The county I work in has an extensive Floodplain Reference Mark system, so I find the nearest marker and hit that with GPS.
- Create a site TBM near the structure with GPS.
- Identify which Diagram the structure is using FEMA instructions so I know what elevations I need.
- Set up my total station using assumed elevations.
- Traverse around the structure getting LAG, HAG, FF, AC Pad, garage FF, and any other elevations I need.
- Shoot the site TBM with Total Station.
- Calculate the GPS adjustment from actual to measured, and apply that adjustment to the site TBM.
- Translate my Total Station elevations to the adjusted site TBM.
- Make pretty notes.
- Take photos of all sides of the structure, LAG, HAG, and any other elevation I shot.
- Submit to office.
Other companies I've worked for have required me to hit three benchmarks and find the average GPS adjustment.
Thanks for the detailed process. That can't be a one-man crew can it? What is the average number of hours spent in the field start to finish? I just don't see how all that field work plus office work can be done for $225-350. What am I missing??
andrewm, post: 389661, member: 10888 wrote: I just don't see how all that field work plus office work can be done for $225-350. What am I missing??
The good sense to let the necessary level of effort drive the fee, rather than "the going rate"?
andrewm, post: 389661, member: 10888 wrote: Thanks for the detailed process. That can't be a one-man crew can it? What is the average number of hours spent in the field start to finish? I just don't see how all that field work plus office work can be done for $225-350. What am I missing??
I am on a two man crew. It could be done solo if I had a robotic total station or a laser level & lenker rod.
It usually takes an hour, but typically I do an EC at the same time as a boundary/title survey.
My company charges the high end of the range you mentioned if it is just an EC, and the lower end if it is done at the same time as a title survey.
But again, I am just a field crew. I have no idea what goes on at the back end in the office.
Jim Frame, post: 389663, member: 10 wrote: The good sense to let the necessary level of effort drive the fee, rather than "the going rate"?
I want to work for you.
I am so frustrated with standard lot & block pricing because they expect me to do every job in the same amount of time.
We are way over that price, about 4 times that and we do 3 or 4 a week. We are in the northeast US. I do them all the time solo with my robot.
Depending on the GPS reading for my site benchmark, the rest only takes 20-30 minutes. Unless the dwelling is enormous and needs a lot of verification. But sometimes the LAG and HAG location can easily be seen by eye so your really only gathering an elevation at 5-6 shots. Maybe a turning point in between.
andrewm, post: 389661, member: 10888 wrote: Thanks for the detailed process. That can't be a one-man crew can it? What is the average number of hours spent in the field start to finish? I just don't see how all that field work plus office work can be done for $225-350. What am I missing??
Well, it really can't! It is being done by people who "...won't make much profit, but keep the field guys busy", and who don't care how badly they damage their profession by doing so. For $225 I can field a crew for 75 minutes - that doesn't include administrative charges, research, travel time or filling out the form. I don't think I could do one for that even if I was paying everyone minimum wage! My price starts at $1200 and goes up...
I suppose that's why I'm having such a hard time with this. With all of my other engineering and GIS work I charge much higher rates. $225 for a minimum of three hours work plus certification by a PLS or PE seems crazy to me. But I called several local firms and the prices were $225, $250, and two at $350. It's not just one place low-balling the prices hurting the profession. Apparently that's the going rate. So if I'm going to do these I have to be in that range. Another factor at play in my mind is the reason there will be a high demand for these. Tens of thousands of people flooded that were below BFE that will forced to get one for a permit and not be happy about it one bit. So now is not really the time to stand on a higher price because of principal. I'll make my margin with my industrial clients. If I can provide a good service to the community and not lose money I'll be happy. And I certainly won't be doing any harm to the profession since the profession in this area already established the price not me. If you want to get angry at someone, I can tell you who I called.
So what it boils down to is what is the most appropriate one-man field procedure that can collect the data using standard industry practice, within FEMA guidelines in about an hour. Right now I'm thinking that procedure is static observation of ~1hr for a TBM nearest the building as possible then laser level loop off that. Separate VRS observations at the beginning and end of the static session as a check. Process static via opus and attach to EC. Is this reasonable?
I almost always use RTK GPS for my certicates.
I set two control points with GPS RTK (we use a network). I occupy the control points for a minimum of three minutes (usually five) on each point. In most cases, I also occupy a known town/city BM. If there isn't a known BM, I'll set my GPS receiver on one of the two control points and collect two-four hours of data to submit to OPUS. Its a great time to read the paper, clean the truck, return emails, etc..
I then come back on another day and re-occupy the control points with my GPS RTK, again for 3-5 minutes. If everything looks good so far, I then take out the robot, set on one control point, backsight the other, check horizontal and vertical between them, and start my locations. I gather LAG, HAG, FF's, a/c pads, decks, etc. Then I take photos and make notes.
About 48-72 hours after I collect my Static data, I'll submit to OPUS, once I get the report back, I compare all my elevations and the proceed to fill out the form.
FYI, I was also always told to round down for the elevations. For example, if I got a floor elevation of 10.18' I was told to round that down to 10.1'
I dont know how anyone can do one of these that cheap. I usually charge $700- $900 depending on the complexity. I do them solo all the time. Even use a level with a bipod. Still takes a few hours in the field and the same in the office.
As a standard practice, I usually set two TBMs with network RTK on site and level between them. Shooting both when I get on site and again when I leave. This is in addition to checking into a published BM who's elevation was established by leveling.
If you're going to get into these, especially using GPS, having a firm understanding of datums and the difference in geoid models is a must. Not all elevations are created equal!
I worked for a company about 15 years ago that was doing EC's for $375. We had established control in these neighborhoods and were doing multiple certs at the same time. If I recall, this was after a major event and the clients were solicited by direct mail.
As I suspected, the demand for ECs has been very high. I have done about 50 of these in the past three weeks. The going rate is $225 - $250. I have a field tech that can do 4 a day by himself. We have refined a process that works well and has checks in place that should catch any blunders. We have run across other surveyors in the field and our process pretty much matches theirs. What I do is setup the GPS on a temporary benchmark and collect a 3-min observed control point using VRS. Then I start a static session that runs while the rest of the data is being collected with a laser level. Obviously I have my tech close the loop back to the benchmark. After the static has run for about 1 hour I end the session and collect another observed control point using VRS. To process the static I originally planned on using OPUS. But there are two CORS stations down in my area and I haven't had much luck processing with OPUS RS. So I use Trimble RTX post processing. I did a lot of testing on benchmarks in my area that were established a few years ago as part of a height modernization study. What I found was Trimble RTX processing was much better than OPUS RS, even if I could get an OPUS solution. VRS has also been inconsistent, sometimes up to 0.5' off. I average the two VRS shots and compare to the RTX static shot. As long as the RTX processed static point is within a few tenths of the VRS, I'll use the RTX static point as my benchmark. One final rough check is using the LSU Ag Center Flood Maps website. They have an interactive website that has the NFHL layer along with lidar data. You can click on a spot and get an approximate ground elevation. It's actually not too bad, usually within 0.5' or so, assuming no fill has been added since the lidar was flown. Using this website would help uncover any large GPS bust.
I feel comfortable that my process should be accurate to within a tenth or so. The only way to get any better is a much longer static session or a crazy long level loop from one of the few good benchmarks around here.
I did have one customer that had an old EC (2003) and we were 2.1' lower on her floor than the previous surveyor. I double checked all my work and didn't find any issues so then I looked closer at her old EC. The previous surveyor used a benchmark about 0.5 miles from her house. I tried to look up the benchmark and it's not listed on the NGS site. I finally was able to locate the data sheet for the benchmark and it was established in 1973 and found in 1987. Since I'm curious to know what's going on, I told my client I would try to go find that benchmark and setup my GPS on it to see what I get. If I can't find the benchmark, I'll go do another static at the TBM at her house as a check. Lidar data where the benchmark should be is in pretty good agreement with the data sheet. And lidar around her house agrees with my results. Her house doesn't have a 2ft thick slab, so I really don't know where the 2.1ft difference could be from.
Not to open a can of worms here but there have been concerns for years about the quality of lidar data for LA. Some felt that it was not properly QCed with the lack of proper ground truthing in many areas. Rough check is even questionable. But if you are getting reasonable tolerances and solutions, then all the better of course.
Because of the opus and CORS situation you have posted.
I would establish a PBM by using NGS guidelines at your home/office to use as a vector transfer. Download CORS data, I know Covg and Hammond are running and I would think BR
Stations are ok. You would need a unit to record static while you were similtaneiudlynestablidhing a TBM at sites.
Then continue to build upon your own network.
You already had 50 sessions to build /develop control.
Sad to hear that the price is being fixed somewhat by demand but it seems Azzwackards to me. For the liability and time and expense, you would think the cost would be more than double.
One of those situations if the proper cost was applied, you would make the same $$ and do a lot less work than the lowballers.
andrewm, post: 393296, member: 10888 wrote:
I did have one customer that had an old EC (2003) and we were 2.1' lower on her floor than the previous surveyor. I double checked all my work and didn't find any issues so then I looked closer at her old EC. The previous surveyor used a benchmark about 0.5 miles from her house. I tried to look up the benchmark and it's not listed on the NGS site. I finally was able to locate the data sheet for the benchmark and it was established in 1973 and found in 1987. Since I'm curious to know what's going on, I told my client I would try to go find that benchmark and setup my GPS on it to see what I get. If I can't find the benchmark, I'll go do another static at the TBM at her house as a check. Lidar data where the benchmark should be is in pretty good agreement with the data sheet. And lidar around her house agrees with my results. Her house doesn't have a 2ft thick slab, so I really don't know where the 2.1ft difference could be from.
My first guess would be NAD27 (the old EC) and yours being NAD83.
Scotland, post: 393375, member: 559 wrote: My first guess would be NAD27 (the old EC) and yours being NAD83.
I don't think the horizontal datum could account for anything here.
Perhaps you mean NGVD29 and NAVD88.
Bill93, post: 393419, member: 87 wrote: I don't think the horizontal datum could account for anything here.
Perhaps you mean NGVD29 and NAVD88.
Yeah... you are correct. I stated horizontal datum. But you got the gist.
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