I got asked to give a price on digging and backfilling for foundation for a 4000sf comercial building. I do mostly residential work so I'm looking for a bit of help on how long this job would take. I was thinking of having my 200 do the digging and having my 160 cast the ground away. All the excess ground will be staying on site. Backfilling will be done with compacted gravel and will be supplied by the customer. Am I approaching this with the right equipment? And how long do you estimate the dig and backfill would take? Soil is silty clay with and average dig depth of 8 feet. Thanks for any help.
I think you might be better off with a dozer, track loader or a wheel loader for the second machine. It looks like you will be moving much of your dirt at least 3 times by the time the foundation is dug out. After that you need to get it back in place. You're 200 will knock that hole out in no time flat but they aren't very efficient when it comes to moving the dirt any distance. After the rough work is done, that 450J in your machinery list will finish off the project nicely.
Need a bit more info. Exactly how far from the excavation is the spoil going to end up? Does it have to be in one pile, or can it be in multiple piles all around the hole? What does the backfill part consist of? Are you filling the entire hole up to an established grade, or are you filling around walls? How much gravel is estimated to be used? For me, the hole would be pretty straightforward. 1300 yds³, I'd figure the excavation to take about 2 days as long as you could keep the dirt away from the 200. Tandem dumps would be your most productive approach, you might struggle to stay ahead of a dirt-slinging 200 with a 160. But also keep in mind the more machines involved, the more the job will cost.
Twisted I don't know if my dozer would be big enough to keep up? Definitely going to need machines on tracks. As we will be going ahead in the next month and things won't be dry.
Shimmy. I am able to stock piles the ground in multiple piles on two sides of the building. No backfilling inside. Just found out. Only where the two entrances are will need to be backfilled on the outside with compacted gravel. The rest can be backfilled with native soil.
Sorry but I meant that your dozer will help to finish grade the job. It will take a good sized machine to keep up to a 200 hoe. As Shimmy said, haul it if it needs to go far or push it if it can stay close. You have done residential jobs so just figure the cubic yards plus the move distance and bid accordingly. We all have different materials and machine prices. Sorry that I can't be more help. my prices are probably much different than much of yours. Location/utilities/owners/materials mean a lot more than cubic yards on a lot of jobs.
I'm not looking for a dollar value. More or less just a estimate on how long it would take with the equipment I have. Thank you for your replies
I would feel pretty comfortable figuring 2 days for the dig. Might need 3 machines for a portion of it, depends on how much bucket you have on the excavators. The filling sounds a bit more involved, reason I say that is compacting up against a wall can be tricky business. Without support inside, you can push the wall in. Around here, we usually put about 2' of ¾" washed rock on top of the drain tile, then the rest is either gravel or soil. The fill is usually just ran in and allowed to settle naturally. I would think a day with a couple of your backhoes and the skidder would be more than enough time to get it filled in.
Two days of digging with your 200 and have the 450 and 279 on site to push/place material in stockpiles. On the backfill side, use your 450 and 279. 450 to push material back to the foundation and run the 279 spreading backfill. Rent a remote trench roller to compact the backfill. I would put two days on backfill depending on dirt testing/weather. How much cutback and sloping does the GC want? That will add material moved to the excavation.
One day to dig with 200 hoe with labor checking grade throwing the dirt to the side. 1/2 day at most with 200 hoe to move spoils enough for cement crew to get around. If you bring your 160 hoe, that guy could move the spoils and check your grade and get it done in one day.:my2c
Object here is to make a little bit of profit. If he tells them one day and it takes two, he's losing money. If he tells them two days, and he finishes it in a day and a half, he looks great and probably makes some money. I've dug dozens of basements, never finished more than a 2500 square foot in one day. This was with a 9030B, 6' bucket, loading spoil on two, sometimes three tandems. Not saying somebody can't do it, I just would never figure less than two days.
I've been operating for over 40 years, started at age 9. When you get stuff done faster (and safer) than others, the phone rings off the hook for you. I would still bid 2 days for profit. Just saying it sounds like one days work.
The other guys on this thread have probably forgotten more about this subject that I know, but I did want to share with you the single most valuable lesson I ever learned on this subject. Literally. I effectively paid $10,000 to learn it. When you're digging a hole it doesn't matter if you're using a shovel or a steam shovel. It's all about taking stuff out of the hole and getting it out of your way. Where it's going and what's going to happen to it matters in the bigger picture but it's a secondary question. The key is your working vs idle time ratio. If one guy's excavator is working 20 minutes out of every hour and another guy's is working 40 minutes out of every hour, the first guy will take twice as long. There's a big digging project here at Buckeye Lake in Ohio that I was watching the other day. There was a steady stream of dump trucks bringing bank run in, others taking mud out and yet another line of articulated dumps taking the bank run out to the berm being built. They had multiple large excavators there that never stopped moving; either filling trucks or adjusting. They were probably around a 50:10 work to idle ratio and the idle time wasn't really idle because the piles needed constant adjustment. The point I'm trying to make is this... The mistake I referred to was in that I based my numbers on how much dirt I could dig in an hour and I didn't stop to consider that I would never actually spend an entire hour digging. By the time I realized my mistake there was no catching up.
:exactly. Anybody can rough a 1300 yd hole in, digging a basement is quite a different story, IMO. If this dig is a square or a rectangle, you might be able to do it in a day. That 160 and the 450 are going to have their hands full keeping the dirt away. He hasn't said what the actual dimensions of the dig are, but if we assume 50' by 80', that means, at minimum, the inside ⅓ of the dirt is going to have to move 50-60', maybe more depending on how far away from the hole it has to be. That's at least three moves with the 160, and the 450 isn't going to push much more than a bucket's worth each push, unless he's running a 36" bucket. I'm not trying to start a fight here, just saying that digging a hole and digging a basement are two completely different animals.