We went to investigate a drain that keeps blocking up.

Step1: Clean and Inspect
We start at the highest point of the blocked drain to discover that, besides for the blockage and roots growth found in the drain, the pipe actually seems to be running uphill for a few meters. This would obviously cause water to sit in the pipe and prevent solids from moving out.

We cleaned the drain and got a camera and tracker into the line to help map out the problem.

The pipe is dipping underneath the wooden floor in the bedroom, so I suspect that there is an open gap and the pipe is just hanging in the air and sagging from lack of support.

Solution:
The next step is to neatly open the wooden floor to expose the pipe. We can keep the damage relatively low. We narrowed the dip in the drain to one area under the floor, which is luckily covered by a bed.

Once we have opened up we can try modify the pipe to get a proper slope for drainage, with better support.