drains far too shallow

[104-1093880317]

I have excavated an area of crazy paving outside our front door (around 100m2). I encountered (and broke) a clay drain taking surface water from the drive. Unfortunately I also discovered that the drain then goes through the house granite wall (underground) and then lies unprotected under the lounge floor (suspended floor 2ft above bare earth). The drain then exits the other side of the house and eventually into a soakaway. All this is rather bizarre, but the real problem I have is that it is a huge amount of work to lower the level of the drain (I would have to dig up the lounge!) or re-route the drain round the house (requiring a 15ft deep trench due to levels). What would be the best way to protect a new drain that would be only 8" below the level of a new block paving area, given that this area only gets pedestrian access?

[84-1093879891]

Haunch it in concrete. At such a shallow depth, and for surface water, I'd weigh up whether it could be completely replaced with a linear drain, and so avoid all the hassle and expense of laying pipework on convcrete, haunching it all, providing flexi-joints every few metres and getting the falls right.

Would that be a possibility on your job?