Gravel was laid down between all the footers and laid the base for our in-floor systems. In the photo below David is putting the air intake through a sleeve in the footer. This will eventually feed fresh air to our wood stove.
It took two full days to install our plumbing and radon vent systems (not to mention the weeks of planning and getting advice from the building inspector). After our plumbing was pressure tested, and inspected, it was covered with gravel to be made ready for insulation and heating tubes.
David designed, and spearheaded the project for our radient floor heating. It took another two full days to install this system. We started by laying down an airtight vapor barrier over the gravel. This included rubber gaskets around each fixture coming from the gravel. On top of this barrier we laid polystyrene insulation. The insulation boards were cut around the footers (because the footer need to bear the weight of the house). Steel mesh was laid on 'crutches' over all of the floor to strengthen the concrete, as well as to hold our hot water tubing in the middle of the floor. Spacing was then measured out, and a separate loop was created with tubing for each room in our basement. The loops all connect to a beautiful manifold in our eventual mechanical room.