Hopefully I can get some advice please, my wife and I bought a bungalow last xmas and we have been slowly working through the jobs on it, we have so far had a re wire and new heating, new bathroom and windows and doors, we are thinking this could be our last move and the house although old and needs modernizing is very nice.
Anyway we have had a wet floor void in the old kitchen which is now a dining area, we traced it to dodgy drainage at the side of the house and did a temp repair but the ground stayed damp as did the outside foundation walls fast forward to last weekend, the drain on the extension backed up so we got a jetter in and a lot of dirt came down the waste line into the manhole and out the other side, i forgot to mention all the drains go into a main drain including the soil pipe as its a 60`s build bungalow, a camera was put down and showed a collapsed pipe, so we assume all the rain water and sink waste has been going into the ground for a few months before it fully collapsed.
Now my question is as the sewer pipe is fine into the manhole, instead of digging all the old drains out at about 12m in length and a meter down can i close the old drains off and install new plastic drains and just run them into the manhole?. Ive attached a drawing and hopefully it is clear to understand, the new drains would be about 400mm below ground I believe and would only carry rain water and shower and sink water.
The soil vent stack was a soil pipe to a loft conversion upstairs that was removed, the other bungalows that have the toilet runnung under the bathroom floor like ours dont have a vent stack, the drainage pipe work is just over a meter from side of house.
I would appreciate any advice please.