digging out 4 inch drain

[drew53813]

From my bathrooms to the front of the house is a good 25 ft run. I am planning on replacing all my old metal and cast iron pipe with ABS. In order to expose this 25 ft section I will need to dig down approx. 2 feet at the deepest point. I have a few questions:

1. what are the dangers of digging out sections of pipe under the house in the crawl space. I have heard (although its rare) of houses caving in from this
2. can I use an air chisel or some kind of pneumatic digging tool to speed up the process.
3. Any other comments would be appreciated.

Thanks- Andrew

 

[hj]

1. Practically zero. IF you have hear of houses collapsing they are apocryphal stories repeated by someone who heard it from his brother who heard it from a guy in the bar, who heard it from his wife after someone in the beauty parlor told her it happened to them.
2. That is how I would do it, unless I hired a couple of illegals to do it.
3.Two feet "at its deepest point" is a very shallow sewer.