Partly Blocked Drain

I have an old property and I am rennovating one of its outbuildings. The drainage from this part of the outbuildings is 4 in diameter fireclay pipe, but until I set about it it did not have any access for rodding and so cannot have been cleared since it was laid ( I think shortly after the War). There is a 30 m length which I can get my rods down with a traveller wheel on the end or with one of those corkscrew like devices. But the rods stop dead if I put anything larger down. Water flows down the pipe, but without the rush which I would expect, as the pipe is at a reasonable grade.
Does anyone have any ideas about how I can get this properly cleared?

only a thought.

shove your rods down with plunger thingy (tehnical term that is) measure how far down it goes, then dig pipe up at that point

Does this length of pipe take soiled water or rain water. If rain water could just be an old soakaway which is why rod stops dead. If it runs to a main drain for soil water you could be digging.
Lee

Could be a cesspit and not on the main drain

one of the joints has dropped on the 4inch saltglazed pipes that are 2 foot long .......more chance of it being done properly when yours was ...than you will find on any new estate today My psychic eye never lies

There also the possibility that there is a trap ( or u bend ) or a rapid change of direction.

If there really is a soft blockage which sounds unlikely ther pressure jetting would go around most bends but I dont think that is the case.

At the distance where it "just stops" whats on the surface ??? Could there be an inspection chamber which has got covered over.

It could also be a "T" connection onto a larger sewer.

Many possibilities and digging at exactly the stop point might be the low tech solution.

I am surprised that DIA did not mention the high tech CCTV option. The small cameras are so small and cheap now that you could put one in a bottle and seal the top and tape it onto your rods and watch as you go !!!


Tony