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View Full Version : Need advice on trenching estimate


StormCat
10-23-2008, 01:06 AM
I need to make a price on a job that I haven't done before that involves digging a trench about 160' long & about 16" to 20" deep by about 8" to 12" wide. It is to install a 6" pvc drainage pipe for the building gutters. It is to be dug across a pretty level gravel parking lot. I have a backhoe attachment for my bobcat but I'm wondering if I shouldn't rent a trencher for this job. I think it wouldn't make as big of a mess and would be quicker. I haven't mastered the backhoe yet anyway. Any ideas on how much time and how much I should charge? I appreciate your advice.

S&MLL
10-23-2008, 02:50 AM
alot. For 6 inch wide pipe you figure 8 inch bucket. Plus thats alot of ground to tamp. Hope you have a tamper or something. But I wouldnt touch that for less then 25 a foot.

Junior M
10-23-2008, 11:24 AM
I would think you would get a better response in the heavy equipment forum, but I wouldnt use a trencher because you are going to have to figure fall in, using a lazer, and it is hard to dig grade with a trencher... I would recommend that hoe attachment...

Junior M
10-23-2008, 09:22 PM
I forgot to add, I would recommend using a 12in bucket, it will be a lil easier on the guy on the grade stake...

And if you are just straight burying the pipe, you dont have to tamp, just push all your dirt over the hole, pile it up a lil and drive up and down the trench with your skid/mini ex and then clean it up with the bucket, hand rake all the junk left on top out and leave...

StormCat
10-23-2008, 10:28 PM
I 've got a 12" bucket that I can use. I believe I can dig it with that bucket. Like I said, I haven't mastered using the backhoe controls yet because I haven't had it very long. But I will work on that. Thanks for the advice jlm335.
It is very helpful.

StormCat
10-23-2008, 10:33 PM
I might add that I did check on a trencher in our area and it would not work. The largest one they have is 6" wide and thats the i.d. of the pipe.

Junior M
10-23-2008, 10:44 PM
Yeah, a trencher just isnt the best thing... I hate a trencher!! Also I hope you have a transit/lazer/or whatever you like to call it, you need to make sure you have enough fall between the beginning of your downspout and the end of your pipe... if you end up not having enough fall, you can try and put fall on it or you can just run it level. I know that sounds ridiculous, but think about it, when you pour water out on a table which way does it go? the quickest way out or off, it will work the same way in the corrugated...


You will get the controls down, you will get to the point your not even thinking, its like your in a dead zone, your just watching the bucket and occasionally thinking of what your going to do next...

Mike33
10-23-2008, 11:25 PM
I do this all the time. I would use either 12 or 24" bucket. It would depend on the siuation and im speaking say blind ditch or french drain. If you have a close to flat area just laying wet 12 will do. If it is say at a bottom of hill where a lot of water is flowing i would go to 24" bucket. Make sure you have fall use laser or transit. Estimating, depends on soil you are digging. If its clay digs easy 2 hours to dig, shale or something hard could take longer. We just did one 425' took 7 hours but we used our 331 mini, had bobcat positioned beside of ditch so we loaded the dirt in bobcat bucket. Then i had to carry dier 200 yards to pile up to haulaway. This prevented me from having a mess and re-do yard. I was able to go straight in and out of yard from blacktop and we didnt spill a wheelbarrow full of dirt in yard. This was a real $ saver in the long run no patching. So you will have to figure labor for excavation, haul away of dirt, pipe, stone, fabric. I would not use a trencher like mentioned you need fall and will not get that. Good luck to you.
Mike

Junior M
10-24-2008, 06:23 PM
Why dont you just give them an hourly quote with an hourly minimum? Thats the way we do it and did it when dad was doing it in Ohio...

Mike can I ask why you say a 24in bucket? For what he is doing I would just use my 12in bucket, he isnt doing anything complicated just some drainage.. The most challenging thing he really has to do is is figure the fall....

AWJ Services
10-24-2008, 06:58 PM
Use an excavator.The smaller the bucket the faster the digging will go.
I would pull the gravel away from my digging path so as not too mix with the spoils.
When done fill it back in and pack.Remove excess dirt and replace gravel.
Should not take more than a day for 2 guys.
I would rent an excavator rather than use the Bobcat attachment.
Will you install the pipe as well?

Mike33
10-24-2008, 09:48 PM
Why dont you just give them an hourly quote with an hourly minimum? Thats the way we do it and did it when dad was doing it in Ohio...

Mike can I ask why you say a 24in bucket? For what he is doing I would just use my 12in bucket, he isnt doing anything complicated just some drainage.. The most challenging thing he really has to do is is figure the fall....

Sure Jim, because i own a 12 and 24" buckets. I think i mentioned in my post not particular his project but some of mine, say i have a slope and the bottom im installing a french drain, blind ditch and im thinking a lot of water coming down the hill i will use my 24". Keep in mind i live in the mountains and water issues is very common around here. I maybe shouldnt of mentioned it in this thread because i didn't want to confuse someone who is really needing help.
Mike

StormCat
10-24-2008, 11:33 PM
I made a bid on the job and he accepted it. He wanted to lay the pipe himself and he has already got it.

I checked on the cost of renting a trencher and excavator and both were pretty high for a day. It would really cut into my profit on this job, so I will have to use what I have. I have a transit to check the fall of the ditch & pipe. I will try to remove what gravel I can before digging the trench.

The parking lot is lower than the building and getting the gutter drains off of it is going to help, but it still will have the run off coming down on it. I recommened putting in a drainage ditch or french drain in while we were doing it but he wanted to wait to see how much difference this makes. I could do it by using a bigger bucket and put it all in the same ditch. I think he will be calling me back later on this. But, it's his business and money.