Dirt Moving Trenching beneath an overhang

[ShenandoahJoe]

I have a 2-level cottage set into a hillside. I'm getting water in the basement, so it's time to put in some drainage pipe. I have to dig a trench along the wall, but that wall is under the middle of the top floor, so I can't get in there with any normal trenching equipment. (Marked with an "X" on the end view below.) There's about 18 inches of air between the floor and the top of the dirt. I have this vague idea that I could drag a bucket on some long chains, and dig out the dirt from the ends. Kind of like a 3PH dirt scoop, but turned backwards and half as big. Would this work? Have you ever heard of anyone who makes such a thing?

 

[MossRoad]

If the bucket bites in, it will act like an anchor and just start going deeper. You'll have to figure out a way to control depth of cut.

What about trenching further out and making a French drain?

 

[Everhard]

Few thoughts:
1: Where's the water originally coming from? If you can answer that can you stop it reaching that middle foundation, then you don't need to drain along that portion of the foundation.
2: Is there drainage at the footing level of the foundation. (proper weeping tile along the perimeter in particular is there any along the high side exterior wall?)
3: If there isn't I'd put in the weeping tile around the house, that along with making sure your eves are draining away and downhill from the foundation should in my mind stop the water from coming in where it is based on that little diagram.

But bear in mind I'm basing my opinion just on just that little diagram. The bigger picture would be more helpful, there might be better solutions to your problem.

E.

 

[100 td]

Fix the cause, not the symptom.
Stop the water before it gets to where it is now.
This would probably mean putting in a larger/deeper rubble drain around the house higher up, and of course upsetting all the landscaping/decking etc.
But in the long run, a far better solution.

That said, miners used winches and digging buckets on cables for following small veins, can't think what they're called, they would be suitable but there will be a lot of work in it I expect. I think (get an engineers report, not my thoughts) you really need to go down deeper than the foundation, and ensure proper piping/geotextile and removal of water as any water that gets there will be sitting and weaken the foundation material. Far better to stop the water before it gets there.
EDIT: Everhard types faster than me!

 

[skyhook]

I have to agree with the others, installing a drain system where your "X" is will only invite more water, weakening your center foundation and soil around it. You need to figure out a way to "divert" the water from the cottage. I'm guessing that your problem is not only surface water from the hill but also veins of water beneath that are finding their way in your "space" and converging on your second foundation, if thats the case, you may have to dig deep, behind the cottage and this may not be feasible for you, I don't know, how far or big of a hill do you have behind the cottage.

 

[jenkinsph]

I am working on a similar job this coming week where the water is running under the house. As the other posters have suggested it is better to divert the water before it gets to the house. I will be working on diversions that start 150 ft up the hill with the last one being about 10 ft from the house. I will have three drainage swales to divert the water away from the last French drain. That puts less water in front of the drain next to the house to deal with. Slower water speed for less erosion damage.

 

[ShenandoahJoe]

I like that answer because it'll be easier to do part of the job. The rest is complicated by a boulder that's as wide as the middle third of the cottage. It sticks up about 8" above the ground, and goes down farther than I've cared to dig. Any suggestions about how to handle that?

The reason I think he boulder doesn't go all the way to the foundation wall, so I can put a drain at the X, is that groundhogs dig burrows along there.

 

[dieselcrawler]

Hire the ground hogs.

 

[arkydog]

bucket sound good if only choose. to keep bucket from getting hung up and flying toward is to put a chain and rope opposite way you are pulling with someone pulling chain, bucket and rope back to set up for another scoop

 

[ShenandoahJoe]

Crawler, if I could figure out a way to make groundhogs useful, I'd spend all my time enjoying the adoration of my fellow Virginians and I wouldn't worry about a little water in the basement.