Flooding likely due to clay drainage tile broken; excavate to replace?

Question

We bought a house 2 years ago which was built in 1952 with an extension added in 1991. The basement of the extension floods with heavy rain/snow, but the original house never floods. There is a sump pit in the original house, picture below included, which constantly has water running into it from the clay pipes that lead to the original house. There is a pipe (white arrow in pic below.) with no water running out of it, in the direction of the extension.

We used a drain inspection camera and found that this pipe leads out of sump pit, out of the house, and it is broken about 1 foot outside the house, 5 feet deep. I can see the tile broken on the camera. This is presumably part of a drainage tile system that exteriorly drains the extension, ie a french drain. Given that it is occluded, the extension basement is flooding.

The best solution seems to be to excavate over the broken location, replace the broken segment, hydrojet out of the rest of it and pray that there are no other broken locations. Plumber quoted us ~$4000 for this. It would be unfortunate to pay that and discover that the entire system is unrepairable and we wasted the money. But it is a lot cheaper than to do a whole new system, especially as it would involve taking down our deck.

Unfortunately, interior french drains are not an option, as we discovered that our basement is a monolithic slab. That is, it has no footing; the wall sits on a single poured concrete floor, which is thus important for structural integrity.

Would you recommend trying to repair the existing weeping tile system? Or is it just not worth trying to repair these and should rather just bite the bullet and do a whole new exterior drain tile system.

Answer 1

Repair will be a gamble. Before throwing $4000 at a plumber it might be well worth your while to dig a hole yourself and see if you have one broken tile, or many broken tiles. You can also do some DIY jetting with a garden hose while you are at it.

Note that you will want to dig a wide enough hole that it's not able to collapse and trap you in the hole, not the tiniest hole that will reach the pipe. More effort, but not killing yourself is a good trade off. You can either rent equipment, hire someone with equipment, or do it with a shovel (depending on soil, a pick as well) the old-fashioned way.