Minni excavator sizing for digging foundation drains

[moparguy55]

I was looking at kubota kx91 and kx121 machines. Im doing my licence now for resedential french drain installs. Looks like around here the kx121 is pretty much same price as the kx91.
What is a good size machine for digging out 8ft basement walls?
Thanks

 

[KSSS]

Space is always an issue digging around existing foundations. While the walls are 8' you also have footings heights of 10" to 12" at least here. Also the walls can be 9' instead of 8', most anything built in the last 20 years is 9' where I am at. I don't know how you are plumbing for these in QC, but if you are gravity flowing to a French drain than you need to be lower than the height of the wall. So you could end up needing a good bit of reach. Assuming you are strictly working with 8' walls with a 12" footing a 35 -45 sized machine would be min. in my view. A zero swing machine would the way to go, even if they are a tad wider than a conv. tailed machine. If you have room I would step up to 50-60 sized machine. Personally I don't do anything with Kubota (not that they are not popular, just not my choice). I would consider the Taki TB138 (zero swing/ zero tail), Wacker Neuson excavators with the VDS option is helpful as it allows you to level the excavator to match the terrain. It is really handy digging drain fields on slopes and working along side houses where they are always on a slope (or should be), Bobcat still offers an extendahoe option on certain excavators I believe. After those machines there are none that really stand out as far as capability beyond what everyone else has. I would consider a quick coupler with multiple buckets sizes and a 40" ditch bucket they are priceless for cleaning dirt off grass without damage. I would also plan for a small hoe pac. Many times those drains run under existing concrete that owners want put back after you tear it out. So being able to compact material back is important. A thumb would be necessary to pull trees, shrubs and concrete. I would chose wisely, consider aux gpm if you are doing a hoe pac. Last thing to consider in my view is that it is always cheaper and easier to rent small mini excavators, so I would spec yourself bigger and rent smaller, rather than the other way around. Good luck.

 

[moparguy55]

Kool thanks. The wacker neuson vds is pretty wild.
Are there any brands to specifically avoid?

 

[KSSS]

Largely I think any of the machines currently available are quality coming from Japan, Korea, USA and Austria. (cant speak to the Chinese models). My experience with Taki, WN, Case/Kobelco, IHI has all been positive. Depending on what you want to do with it, some machines have features that might make it more attractive than another (I tried to highlight some of the ones that come to mind for your application. An example that we discussed on this forum awhile ago was concerning running brush mower/mulchers. CAT runs only one pump on their mini excavators. The only machines that I know that do that, they seem to dig fine, but are not the machine of choice if you need to multifunction especially with a high aux demand attachment like a brush mower. IHI for example runs 4 pumps and they are excellent multifunctioning machines. Where your primarily digging, they all will compare similarly in durability. Depending on how particular you are, you will notice they all will have a slightly or significant difference in feel, speed and ergonomics.

 

[rondig]

The narrowest that will get to depth..we use a U25 kubota...remember our biggest problem is not depth or width...it is those darn low eves...our U35 was always too tall at the knuckle to fit under eves to swing..and our u 25 is the only machine i own with no cab....no cab is great in tight spots...

 

[rondig]

Oh...and the best invention ever is our kubota track wheel barrow....saves so much time.

 

[rondig]

Avoid any brand that has no support locally.

 

[KSSS]

good point on overhead clearance, that can be a problem. I certainly get how local support is important, and while my thoughts on it will put me in the minority, a mini ex is one of the machines that I don't get overly excited about having support real close. There just does not seem to be a lot issues with them. My personal example is I had an IHI that I put 3500 hours on, and never had anything serious go wrong with it, what I did need from IHI, Compact Excavator Sales (the importer of IHI) was amazing. Next day parts, great service. For me they were the example on how to take care of customers, especially since they are in KY and I am in Idaho. It helps that the excavator is a quality machine, but generally speaking it does make life easier if you have local access to the dealer.

 

[rondig]

I had an ihi 35....it was a really good machine...bought it cheap at auction....it had kubota engine....and dakin hydraulics....it was smooth for its age ( 12 years ago)...we sold it with 5600 hrs and all good except pins were a little loose....got same money as paid and put over 3000 hrs on it...unfortunately no dealers around here

 

[KSSS]

I had the same machine. I bought it cheap and sold it for the same money. Probably one of the best mini excavators that no one really knows about. Closest dealer for me was in SLC. 4 hours away, but like I said I got great support from Compact Equipment Sales in Ky.

 

[JD8875]

I love my IHI 30NX! I've dug out several basement walls with it. Generally run a 2ft bucket that gives me enough offset to reach tight against the concrete wall without peeling off the siding with the boom. 8ft walls with 12 to 18 inches of exposure to grade aren't too bad. If they get deeper I bench the machine down which helps slope the excavation, buys me overhead clearance, and improves my cycle times greatly. When my IHI moves to retirement I'll look at another one, although I recently saw they have been acquired by the nearly obsolete KATO corporation. Not sure what that's going to mean. Hopefully they don't kill a great bargain brand.

John

 

[moparguy55]

How long is it taking you guys roughly to dig out a say 40*30 house?
In my head im thinking a drain job on a house that size without any obstacles be a good 30-40hr job by the time pressure wash wall/dry and spray on weatherproofing and new drains.

 

[KSSS]

I love my IHI 30NX! I've dug out several basement walls with it. Generally run a 2ft bucket that gives me enough offset to reach tight against the concrete wall without peeling off the siding with the boom. 8ft walls with 12 to 18 inches of exposure to grade aren't too bad. If they get deeper I bench the machine down which helps slope the excavation, buys me overhead clearance, and improves my cycle times greatly. When my IHI moves to retirement I'll look at another one, although I recently saw they have been acquired by the nearly obsolete KATO corporation. Not sure what that's going to mean. Hopefully they don't kill a great bargain brand.

John

I saw that as well. I also hope that KATO works for IHI. Really quality product.

 

[KSSS]

How long is it taking you guys roughly to dig out a say 40*30 house?
In my head im thinking a drain job on a house that size without any obstacles be a good 30-40hr job by the time pressure wash wall/dry and spray on weatherproofing and new drains.

Never seen one that was totally without obstacles, there are always water, sewer and power to contend with. On the excavation side, depending on the machine, I would dig it in a day and backfill in another. Are you putting clean gravel over the drain pipe? or wrapping the pipe and gravel in geo textile? or using the prewrapped drain pipe? That all would take time.

 

[moparguy55]

Clean gravel and wrap pipe and gravel in geo. Was figuring 4 days solo.

 

[KSSS]

Here is what I use for jobs like that, I assume you have a skid steer. Load the box with your gravel and pull it up on top of your spoil pile that you leveled off. I use it like a mobile gravel box. Pull the gravel out of the box with your excavator with a clean out bucket (40" or so with clean cutting edge no teeth). very neat, no wasting gravel and no hand labor to speak of.

https://www.quickattach.com/p-35926-big-dump.html

 

[suladas]

Yea for that size of house should dig it out easy in 8 hours, next day waterproofing and rock, last day maybe 4 hours backfill if not worried about compacting. Here generally only service to worry about is gas, most older homes power is overhead, water/sewer you can go inside first but generally well under bottom of footing. I like my 6 ton Takeuchi for them, a bit tight in some areas but digs fast. The eves can be a problem for sure but once you've got a hole you just position accordingly. The biggest issue I found with these is room for piling dirt. Only ran one rental wacker neuson once, but it was absolute garbage. Only had 2000 hours on it but controls were awful so sloppy, had no power at all. My TB153FR would dig circles around it.

 

[moparguy55]

Are you guys putting new soil ontop of the gravel? Or reusing the dug out earth?

 

[rondig]

Well i usually dig out top soil and stock pile that( usually 3 to 9 inches deep and 3 ft wide).also serves as a bench for trench safety and it lowers my height clearance for digging. Then we use gravel on top of pipe...then use existing soil to backfill...we use compaction so we dont have to come back next year...then we use topsoil for final grade.....btw dont forget to test whole system before back fill...we use a dumpster looking attachment on our skid steer to haul dirt away we also use a kc kubota wheel barrow when space to place excavated dirt is limited.

 

[suladas]

Depends on what the customers wants but generally most want it done the cheapest way. Which is removing and hauling away any concrete, but aside from that putting all the same dirt back in the hole, no compaction let it settle. Most of the time they are going to re landscape yard anyway, and just leave it for a year to let it settle. Also need to consider shape of foundation, packing can cause issues with older foundations especially if they already have cracks. Separating topsoil is easy if lots of room, but most of the time there isn't here, more cost effective to just replace with new after as it's so cheap.