I've got a vertical clay pipe on the corner of my house that my downspouts drain into. I had to move it over a few inches and up a few feet, so I dug out the top section of clay pipe and used a couple of 4" PVC fittings to get it in the right place. The PVC fits very snugly into bell of the clay pipe, so I just packed it in crushed stone, tamped everything down real good and continued filling in the hole. I figure that this joint is far better than clay-clay joint that was there previously, so I'm not too worried about it.
Going from PVC back to the clay tile is another story. There is about a 1/4" gap between the outside of the clay pipe and the inside of the the PVC fitting. I need to to keep dirt, roots and various other funk from finding its way into the pipe, so I was thinking of just packing the joint with oakum and topping it off with silicone.
Can anyone think of a better way to seal this joint? It will be below grade with direct contact to soil, so I don't thing a banded coupling will hold up very well (and I've been looking for an excuse to use up this bag of oakum).
Any thoughts are appreciated.