Once the drain pipe is laid to the right elevation and location we backfill with 12″ of clean drain crush, in this case we had to bring the drain crush higher to avoid any future hydrostatic pressure on the exterior face of the foundation wall and allow water to flow faster down to the draind pipe below.
At this stage we started backfilling with good drain soil and compaction to avoid any uncontrolled settling of the soil.
At this stage we put in place Radon crush and a 4″ Radon pipe this chimney was connected to the horizontal fan and evacuated outside of the crawspace.