Hi,

We need to pass a single cable accross the width under our stone patio that butts right up to our house (concrete foundation). The propsoed solution is to simply lift the stones up and out of the way and then make a trench trhough the levelling stone and base as needed. Then refill the trench and relay the stones. The problem is that, by next summer, the stones will shift even if you tamp the stone bed/levelling sand/stones.

I’ve seen various solutions going under the patio stones without lifting them up, including: hydraulic jet (aka pressure washer nozzle), ramming a conduit under and using an electrician’s flxible auger (I’ve seen these options discussed on this website too).The hydraulic jet will likely cause its own problems when the water gets to the concrete foundation wall where it has no where good to go and likley disturb the soil as well. The other two options seem good to me.

The person proposing the trench solution says that you will not be able to know where the tip will exit against the concrete foundation wall. However, all of the youtube videos I’ve seen show very good accuracy with either ramming a metal conduit (by hand) or drilling a long flexible auger bit with a drill. Is this just video magic?

With the last two options, we can lift perhaps only one stone next to the house and dig down to meet the conduit pipe or the auger. One stone against the house lifted out of the way is not likely to be as bad as one or two rows across the entire width!

Are all the videos i’ve seen just setups or are these techniques fairly accurate? I could even see using a metal detector to confirm where the pipe/auger ends up!

Look forward to your comments!