Clay Dainage Pipe Blocked

[AnthonyRad]

Hi all,

Bought a doer upper which hadn’t had any maintenance for years.
Front facing wall of the house was like a marsh around the grid above a clay drainage pipe which the kitchen sink/washing machine fed into.

After I scooped about a foot’s worth of water out of the claypipe, I’ve found what appears to be a blockage which is grey and compacted (only way to describe appearance is it looks like plasterboard adhesive mixed up). I can scrape the surface of it with something sharp and and a little bit scrapes off but the rest is in solid. Any water going in has been draining into the surrounding soil through a joint in the pipe (where the green arrow is).

What is the best method of removing this blockage? Jet spraying, boiling water etc? Not sure if rods would be able to dislodge.

Thanks

Further info: Property is semi detached and the clay pipe at the blockage area turns 90 degrees towards the neighbours side and i assume joins their pipe (as they have the exact same setup) then again I assume at the party wall join it turns 90 degrees inwards to tee into the main sewer pipe running underneath the foundations of our properties.

 

[Aquarius]

Break it up into smaller pieces, empty and plenty of hot water down the gulley, looks a bit like solidified fat/grease.

 

[snowhead]

As above, don't hit it too hard but it's probably got a crust on it and softer underneath.

 

[WC1]

You'll tell by the smell if it's grease
What's the pipe wrapped in gaffer tape?