Hi, I know this has been covered and I have read a few things but just to clarify in my mind what is required by regs. We will early next year be starting a rear extension. The shared sewer for a few houses will run through the foundations approx 100mm above base of trench at 90 degrees. Am I right in saying I shutter the full depth and obviously width of trench either side of the pipe back fill with pea shingle then lintel straight on top of concrete, then build straight on top of lintel. In other words the lintel sits on the surface of the concrete. One last thing what size lintel is used please. Many thanks